Content Review Notes for Parents and Students

Revised September 3, 2014

Content Review Notes for

Parents and Students

Grade 8 Physical Science

2014-2015


This resource is intended to be a guide for parents and students to improve content knowledge and understanding in preparation for the cumulative Grade 8 Science Standards of Learning test. The information below is detailed information about the Standards of Learning taught in grade 8 physical science and comes from the Science Standards of Learning Curriculum Frameworks, issued by the Virginia Department of Education. The Curriculum Framework in its entirety can be found at the following website.

http://www.doe.virginia.gov/testing/sol/standards_docs/science/2010/curriculum_framewk/physical_science.pdf

PS.1 The student will demonstrate an understanding of scientific reasoning, logic, and the nature of science

by planning and conducting investigations in which a) chemicals and equipment are used safely; b) length, mass, volume, density, temperature, weight, and force are accurately measured; c) conversions are made among metric units, applying appropriate prefixes; d) triple beam and electronic balances, thermometers, metric rulers, graduated cylinders, probeware,

and spring scales are used to gather data; e) numbers are expressed in scientific notation where appropriate; f) independent and dependent variables, constants, controls, and repeated trials are identified; g) data tables showing the independent and dependent variables, derived quantities, and the number

of trials are constructed and interpreted; h) data tables for descriptive statistics showing specific measures of central tendency, the range of the

data set, and the number of repeated trials are constructed and interpreted; i) frequency distributions, scatter plots, line plots, and histograms are constructed and interpreted; j) valid conclusions are made after analyzing data; k) research methods are used to investigate practical problems and questions; l) experimental results are presented in appropriate written form; m) models and simulations are constructed and used to illustrate and explain phenomena; and n) current applications of physical science concepts are used.

Systematic investigations require standard measures and consistent and reliable tools. International System of Units (SI or metric) measures, recognized around the world, are a standard way to make measurements.

http://www.doe.virginia.gov/testing/sol/standards_docs/science/2010/curriculum_framewk/physical_science.pdf


When I measure…

I will use… The units used

are… The instrument looks like…

Mass Triple Beam Balance

Milligrams Grams

Kilograms

Volume Graduated Cylinder

Milliliters

Liters

Temperature Thermometer Degrees Celsius

Kelvin

Volume Beaker Milliliters

Liters

Length Metric Ruler

Millimeters Centimeters

Meter Kilometers

Force/Weight Spring Scale Newtons

http://www.sks-science.com/images/OHAU-710-00LRG.jpg


Systematic investigations require organized reporting of data. The way the data are displayed can make it easier to

see important patterns, trends, and relationships. Frequency distributions, scatter plots, line plots, and histograms

are powerful tools for displaying and interpreting data.

Data Tables

A line graph shows data that changes continuously; such as temperature and time

A circle or pie graph shows parts of a whole; percentages.

A bar graph compares data; trends

A scatter plot is a graph in which two sets of data are plotted in pairs.


A frequency distribution table shows how often each value occurred.

A histogram is a bar graph that shows the frequency of data within specific intervals.

Investigation not only involves the careful application of systematic (scientific) methodology, but also includes the review and analysis of prior research related to the topic. Numerous sources of information are available from print and electronic sources, and the researcher needs to judge the authority and credibility of the sources.

To communicate the plan of an experiment accurately, the independent variable, dependent variable, and constants must be explicitly defined.

The independent variable (IV) is the factor that is manipulated or changed.

The dependent variable (DV) is the factor that is a measured response to the change.

The constants are the factors that remain the same for each testing group.

The control is a non-tested group used for comparison with the tested group.

The derived quantity (DQ) is the mean of the trials for each level of change.


The number of repeated trials needs to be considered in the context of the investigation. Often “controls” are used to establish a standard for comparing the results of manipulating the independent variable. Controls receive no experimental treatment. Not all experiments have a control, however.

1 tsp of glycerin 2 tsp of glycerin 3 tsp of glycerin

Trial 1 5 mm 10 mm 10 mm

2 10 mm 25 mm 5 mm

3 10 mm 20 mm 5 mm

DQ 8.3 mm 18.3 mm 6.6 mm

IV: Amount of glycerin

DV: Diameter of the bubble (millimeters)

Constants: Original soap solution (2 parts water to 1 part Joy) Amount of soap solution Wands

Control: Original soap solution (no glycerin added)

The analysis of data from a systematic investigation may provide the researcher with a basis to reach a reasonable conclusion. Conclusions should not go beyond the evidence that supports them.

Additional scientific research may yield new information that affects previous conclusions.

When concluding your scientific investigation lab report you will need to develop three paragraphs that will explain what happened in your lab investigation:

A conclusion is a direct interpretation of the data. It should generally analyze the cause-and-effect relationship between the independent and dependent variable established in the hypothesis.

CONCLUSION: Analyze the results and draw conclusions by: Describing the results and explaining what they mean. Describing major findings and site reasons for major findings. Describing how the data supported or did not support your hypothesis. Making recommendations for improving the experiment and what needs to be investigated further.

Different kinds of problems and questions require differing approaches and research. Scientific methodology almost always begins with a question, is based on observation and evidence, and requires logic and reasoning. Not all systematic investigations are experimental.

The type of data and the way it is collected depend on the kind of question being studied. The two broad categories are field research (usually done in nature) and experimental research (usually done in a lab).

It is important to communicate systematically the design and results of an investigation so that questions, procedures, tools, results, and conclusions can be understood and replicated.

The Scientific Method

1. Identify the problem by asking a question.

2. Form a hypothesis.

3. Perform an investigation/experiment to test your hypothesis. (Repeat 3 times).

4. Analyze the data gained from your investigation/experiment.

5. Draw your conclusion.

Some useful applications of physical science concepts are in the area of materials science (e.g., metals, ceramics, and semiconductors).

Nanotechnology is the study of materials at the molecular (atomic) scale. Items at this scale are so small they are no longer visible with the naked eye. Nanotechnology has shown that the behavior and properties of some substances at the nano-scale (a nanometer is one-billionth of a meter) contradict how they behave and what their properties are at the visible scale.


New discoveries based on nano-science investigations have allowed the production of superior new materials with improved properties (e.g., computers, cell phones).

PS.1, Scientific Investigation

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PS.2 The student will investigate and understand the nature of matter. Key concepts include

a) the particle theory of matter; b) elements, compounds, mixtures, acids, bases, and salts; c) solids, liquids, and gases; d) physical properties; e) chemical properties; and f) characteristics of types of matter based on physical and chemical properties.

The critical scientific concepts developed in this standard include the following:

Matter is anything that has mass and occupies space. All matter is made up of small particles called atoms. Matter can exist as a solid, a liquid, a gas, or plasma.

According to the particle theory of matter, the phase of matter is determined by its particles and motion of particles.


Characteristics of Solids, Liquids, Gases and Plasma

solids liquids gases plasma

retain a fixed volume and shape

have a fixed volume take the shape of the

container it is in

take the shape and volume of the container it is in

no fixed shape no fixed volume

are not easily compressible

have little free space between particles

are not easily compressible

have little free space between particles

are compressible have lots of free space

between particles

is compressible particles are broken apart

do not flow easily have particles that

cannot move/slide past one another

flow easily have particles that can

move/slide past one another

flow easily have particles that can

move/slide past one another

particles flow easily stars/sun extremely high

temperatures

Matter can be classified as elements, compounds, and mixtures. The atoms of any element are alike but are different from atoms of other elements. Compounds consist of two or more elements that are chemically combined in a fixed ratio. Mixtures also consist of two or more substances, but the substances are not chemically combined. Elements are classified as metals, metalloids, and nonmetals.

METALS METALLOIDS NONMETALS

Conduct electricity and heat well

Semiconductors Poor conductors of electricity and heat

Malleable Somewhat malleable and ductile

Brittle

Ductile Can be lustrous or dull Dull

Most are solids at room temperature

Lustrous

Compounds can be classified in several ways, including: - acids, bases, salts

- inorganic and organic compounds.

ACIDS BASES

Taste sour Taste bitter

Produce a burning or itchy feeling on skin

Feel slippery to the touch

Are corrosive Are corrosive

Dangerous chemicals Dangerous chemicals

Produce hydrogen ions in water Produce hydroxide ions in water

Examples: vinegar and lemon juice Examples: soap and ammonia

When testing for acids, acids turn blue litmus paper pink.

When testing for bases, base turn red litmus paper blue

Acids have a pH of 1, 2, 3, 4, 5, or 6 Bases have a pH of 8, 9, 10, 11, 12, 13, 14

The lower the pH number the stronger the acid (pH 1, pH 2, pH 3)

The higher the pH number the stronger the base (pH 12, pH 13, pH 14)

The closer the pH number is to 7, the weaker the acid

The closer the pH number is to 7, the weaker the base


Salts are formed by chemically combining an acid and a base. Salts are a neutral substance having a pH of 7.

o inorganic and organic compounds.

Organic compounds contain at least one carbon bonded to a hydrogen and inorganic compounds do not. Acids make up an important group of compounds that contain hydrogen ions. When acids dissolve in water,

hydrogen ions (H+) are released into the resulting solution. A base is a substance that releases hydroxide ions (OH–) into solution. pH is a measure of the hydrogen ion concentration in a solution. The pH scale ranges from 0–14. Solutions with a pH lower than 7 are acidic; solutions with a pH greater than 7 are basic. A pH of 7 is neutral. When an acid reacts with a base, a salt is formed, along with water.

Matter can be described by its physical properties, which include shape, density, solubility, odor, melting

point, boiling point, and color. Some physical properties, such as density, boiling point, and solubility, are characteristic of a specific substance and do not depend on the size of the sample. Characteristic properties can be used to identify unknown substances.

Equal volumes of different substances usually have different masses. Matter can also be described by its chemical properties, which include acidity, basicity, combustibility, and

reactivity. A chemical property indicates whether a substance can undergo a chemical change.

Physical Changes Chemical Changes

Aluminum foil is cut in half. Milk goes sour.

Clay is molded into a new shape. Jewelry tarnishes.

Butter melts on warm toast. Bread becomes toast.

Water evaporates from the surface of the ocean. Rust forms on a nail left outside.

A juice box in the freezer freezes. Gasoline is ignited.

Rubbing alcohol evaporates on your hand. Hydrogen peroxide bubbles in a cut.

Food scraps are turned into compost in a compost pile.

A match is lit.

You take an antacid to settle your stomach.

Your body digests food.

You fry an egg.


PS.2, Basic Nature of Matter

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PS.2, Basic Nature of Matter

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PS.3 The student will investigate and understand the modern and historical models of atomic

structure. Key concepts include a) the contributions of Dalton, Thomson, Rutherford, and Bohr in understanding the atom; and b) the modern model of atomic structure.


Many scientists have contributed to our understanding of atomic structure.

The atom is the basic building block of matter and consists of subatomic particles (proton, neutron, electron, and quark) that differ in their location, charge, and relative mass. Protons and neutrons are made up of smaller particles called quarks.

A proton is a subatomic particle with a positive electric charge. A neutron is a subatomic particle that does not have an electric charge. An electron is a subatomic particle with a negative electric charge. Protons and neutrons are found together in the center, or nucleus, of an atom. Electrons are found orbiting the nucleus. The overall charge of an atom is determined by the number of positively charged protons and negatively charged electrons. If the number of protons is equal to the number of electrons, the positive and negative charges are balanced making the atom stable/neutral. If the number of protons exceeds the number of electrons or the number of electrons exceeds the number of protons, the positive and negative charges are unbalanced making the atom unstable.

Size at the atomic level is measured on the nanoscale.


Scientists use models to help explain the structure of the atom. Their understanding of the structure of the atom continues to evolve. Two models commonly used are the Bohr and the “electron cloud” (Quantum Mechanics) models. The Bohr model does not depict the three-dimensional aspect of an atom, and it implies that electrons are in static orbits. The “electron cloud” model better represents our current understanding of the structure of the atom.

Dalton’s Model: Matter is made of atoms that cannot be created or destroyed. Atoms that are exactly alike form an element. Atoms join with other atoms to form new substances. Thomson’s Model: A positive material with negatively charged particles throughout the positive material.

Rutherford’s Model: A positively charged nucleus surrounded by empty space in which electrons travel around the nucleus. Bohr’s Model: A positively charged nucleus with definite paths/levels/shells in which electrons travel around the nucleus. Electron Cloud: A positively charged nucleus with regions around the nucleus in which electrons travel.

Dalton’s Model Thomson’s Model Rutherford’s Model Bohr’s Model Electron Cloud


PS.3, Historical Models/Atomic Structure: Answers in the back of the book.

24 How is the modern model of an atom different from the Bohr atomic model? A The masses of the atomic particles are different. B The numbers of electrons are different. C The shapes of the nuclei are different. D The arrangements of the electrons are different.

34 A student makes a drawing of a carbon atom. Which of these should the student show in the nucleus of the atom? A Ions B Protons C Electrons D Molecules

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PS.4 The student will investigate and understand the organization and use of the periodic table of elements to obtain information. Key concepts include a) symbols, atomic number, atomic mass, chemical families (groups), and periods; b) classification of elements as metals, metalloids, and nonmetals; and c) formation of compounds through ionic and covalent bonding.


There are more than 110 known elements. No element with an atomic number greater than 92 is found naturally in measurable quantities on Earth. The remaining elements are artificially produced in a laboratory setting. Elements combine in many ways to produce compounds that make up all other substances on Earth.

The periodic table of elements is a tool used to organize information about the elements. Each box in the periodic table contains information about the structure of an element.

An atom’s identity is directly related to the number of protons in its nucleus. This is the basis for the arrangement of atoms on the periodic table of elements.

The vertical columns in the table are called groups or families. The horizontal rows are called periods.

Elements in the same column (family) of the periodic table contain the same number of electrons in their outer energy levels. This gives rise to their similar properties and is the basis of periodicity — the repetitive pattern of properties such as boiling point across periods on the table.

The periodic table of elements is an arrangement of elements according to atomic number and properties. The information can be used to predict chemical reactivity. The boxes for all of the elements are arranged in increasing order of atomic number. The elements have an increasing nonmetallic character as one reads from left to right across the table. Along the stair-step line are the metalloids, which have properties of both metals and nonmetals.

The nonmetals are located to the right of the stair-step line on the periodic table.


Families or Groups of the Periodic Table Family or Group 1:

Consists of the nonmetal hydrogen and the alkali metals Hydrogen is a reactive gas that reacts explosively with water and has 1 electron in its outermost energy

level Alkali metals:

1. Have 1 electron in their outermost energy level 2. Are very reactive 3. Are soft 4. Are silver-colored 5. Have luster 6. Have low density

Family or Group 2 is the alkaline-earth metals. Alkaline-earth metals: Have 2 electrons in their outermost energy level Are very reactive, but not as active as alkali metals Silver-colored More dense than alkali metals

Family or Groups 3-12 are the transition metals. Transition metals: Have 1 or 2 electrons in their outermost energy level Are less reactive than alkali and alkaline-earth metals Have luster Are good conductors of thermal energy and electric current Have higher melting points and densities than alkali and alkaline-earth metals, except for mercury

Family or Group 13 is the boron group. The boron group:


Consists of metals and metalloids Has 3 electrons in their outermost energy level Is reactive Is a solid at room temperature

Family or Group 14 is the carbon group. The carbon group: Consists of metals, nonmetals, and metalloids Has 4 electrons in their outermost energy level Is a solid at room temperature

Family or Group 15 is the nitrogen group. The nitrogen group: Consists of metals, nonmetals, and metalloids Has 5 electrons in their outermost energy level Is a solid at room temperature

Family or Group 16 is the oxygen group. The oxygen group: Consists of metals, nonmetals, and metalloids Has 6 electrons in their outermost energy level Is reactive Is a solid at room temperature, except for oxygen

Family or Group 17 is the halogens. Halogens: Consist of nonmetals Have 7 electrons in their outermost energy level Are very reactive Are poor conductors of electric current React violently with alkali metals to form salts

Family or Group 18 is the noble or inert gases. Noble or inert gases: Consist of nonmetals Have 8 electrons in their outermost energy level, except for helium which has 2 electrons in its outermost

energy level Are not reactive (unreactive) Are colorless gases Are odorless gases Are gases at room temperature

Metals tend to lose electrons in chemical reactions, forming positive ions. Nonmetals tend to gain electrons in chemical reactions, forming negative ions.

Gaining or losing electrons makes an atom an ion.

Gaining or losing neutrons makes an atom an isotope. However, gaining or losing a proton makes an atom into a completely different element.

Atoms react to form chemically stable substances that are held together by chemical bonds and are represented by chemical formulas. To become chemically stable, atoms gain, lose, or share electrons.

Compounds are formed when elements react chemically. When a metallic element reacts with a nonmetallic element, their atoms gain and lose electrons respectively, forming ionic bonds. Generally, when two nonmetals react, atoms share electrons, forming covalent (molecular) bonds.

Non-metal Element + Non-metal Element = Covalent Bond Metal Element + Metal Element= Ionic Bond


PS.4, Organization of The Periodic Table

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PS.4, Organization of The Periodic Table

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PS.5 The student will investigate and understand changes in matter and the relationship of these changes to the Law of Conservation of Matter and Energy. Key concepts include

a) physical changes; b) chemical changes; and c) nuclear reactions.


Matter can undergo physical and chemical changes. In physical changes, the chemical composition of the substances does not change. In chemical changes, different substances are formed. Chemical changes are often affected by the surface area/volume ratio of the materials involved in the change.

Physical Changes

are changes in shape, size, and phase that do not change the identity of a material or create a new substance

Examples: Shattering glass (a change in size and

shape) Water changing from a liquid to a solid

(a change in phase)

involve physical properties

most can be easily reversed

Examples: water (a liquid) changes to ice (a solid)

by freezing ice (a solid) can be changed back to

water (a liquid) by melting

beginning and ending material is the same

are affected by temperature

Examples: An increase in temperature causes

materials to expand A decrease in temperature causes

materials to contract

can combine one substance with another substance without creating a new substance

materials/substances can be separated physically

Example: Sugar can be dissolved in tea. (If left in a

cup, over time the tea would evaporate leaving sugar crystals in the cup.)

Raisins and bananas can be combined in a bowl. (The raisins and bananas can be separated by sorting.)

The Law of Conservation of Matter (Mass) states that regardless of how substances within a closed system are changed, the total mass remains the same. The Law of Conservation of Energy states that energy cannot be created or destroyed but only changed from one form to another.


PS.5a, Physical Changes

PS.5 The student will investigate and understand changes in matter and the relationship of these changes to the Law of Conservation of Matter and Energy. Key concepts include

c) nuclear reactions. describe, in simple terms, the processes that release nuclear energy (i.e., nuclear

fission and nuclear fusion). Create a simple diagram to summarize and compare and contrast these two types of nuclear energy.

evaluate the positive and negative effects of using nuclear energy.

A type of change that occurs can be nuclear reactions. Nuclear energy is the energy stored in the nucleus of an atom. This energy can be released by joining nuclei together (fusion) or by splitting nuclei (fission), resulting in the conversion of minute amounts of matter into energy. In nuclear reactions, a small amount of matter produces a large amount of energy. However, there are potential negative effects of using nuclear energy, including radioactive nuclear waste storage and disposal.

A nuclear reaction is a change involving the nucleus of an atom. The nucleus stores great amounts of energy, called nuclear energy.

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There are two types of nuclear reactions:

Nuclear Fission- a large nucleus of an atom splits into two or more smaller nuclei, releasing energy.

** Remember “fission” means to separate.

In some regions, humans also depend on nuclear fission. Nuclear power plants use this type of

reaction to produce electricity. The energy released during nuclear reactions is used to heat water.

The steam that is then produced is used to turn a turbine attached to an electric generator.

Advantages of Fission Disadvantages of Fission

Producing great amount of energy. Health problems due to radioactive waste

that is produced.

Nuclear Fusion-two small nuclei are joined together to produce a large nucleus and energy. ** Remember “fusion” means to join together.

*Humans depend on nuclear fusion every day because this is the type of reaction occurs in the Sun. The energy released during this nuclear reaction in the Sun reaches the Earth as heat and light.


PS.6 The student will investigate and understand forms of energy and how energy is transferred and transformed. Key concepts include a) potential and kinetic energy; and b) mechanical, chemical, electrical, thermal, radiant and nuclear energy.

differentiate between potential and kinetic energy. use diagrams or concrete examples to compare relative amounts of potential and kinetic

energy. identify and give examples of common forms of energy. design an investigation or create a diagram to illustrate energy transformations.


Energy is the ability to do work: Energy makes change; it does things for us. It moves cars along the road and boats over the water. It bakes a cake in the oven and keeps ice frozen in the freezer. It plays our favorite songs on the radio and lights our homes. Energy makes our bodies grow and allows our minds to think. People have learned how to change energy from one form to another so that we can do work more easily and live more comfortably.

Energy exists in two states. Potential energy is stored energy based on position or chemical composition. Kinetic energy is energy of motion. Students should know that the amount of potential energy associated with an object depends on its position. The amount of kinetic energy depends on the mass and velocity of the moving object.

Important forms of energy include radiant, thermal, chemical, electrical, mechanical, and nuclear energy. Visible light is a form of radiant energy and sound is a form of mechanical energy.


Kinetic Energy Examples: Potential Energy Examples:

Electrical Energy is the movement of electrical charges. Everything is made of tiny particles called atoms. Atoms are made of even smaller particles called electrons, protons, and neutrons. Applying a force can make some of the electrons move. Electrical charges moving through a wire is called electricity. Lightning is another example of electrical energy. Radiant Energy is electromagnetic energy that travels in transverse waves. Radiant energy includes visible light, x-rays, gamma rays and radio waves. Light is one type of radiant energy. Solar energy is an example of radiant energy. Thermal Energy, or heat, is the internal energy in substances, the vibration and movement of the atoms and molecules within substances. Geothermal is an example of thermal energy. Motion Energy is the movement of objects and substances from one place to another. Objects and substances move when a force is applied according to Newton’s Laws of Motion. Wind is an example of motion energy. Sound is the movement of energy through substances in longitudinal (compression/rarefaction) waves. Sound is produced when a force causes an object or substance to vibrate, the energy is transferred through the substance in a wave.

Chemical Energy is energy stored in the bonds of atoms and molecules. It is the energy that holds these particles together. Biomass, petroleum, natural gas, and propane are examples of stored chemical energy.

Stored Mechanical Energy is energy stored in objects by the application of a force. Compressed springs and stretched rubber bands are examples of stored mechanical energy.

Nuclear Energy is energy stored in the nucleus of an atom, the energy that holds the nucleus together. The energy can be released when the nuclei are combined or split apart. Nuclear power plants split the nuclei of uranium atoms in a process called fission. The sun combines the nuclei of hydrogen atoms in a process called fusion. Scientists are working on creating fusion energy on earth, so that someday there might be fusion power plants.

nergy can be transformed from one type to another. In any energy conversion, some of the energy is lost to the

environment as thermal energy.

Law of Conservation of Energy Conservation of energy is not saving energy. The law of conservation of energy says that energy is neither created nor destroyed. When we use energy, it doesn’t disappear. We change it from one form of energy into another.

A car engine burns gasoline, converting the chemical energy in gasoline into mechanical energy. Solar cells change radiant energy into electrical energy. Energy changes form, but the total amount of energy in the universe stays the same. Scientists at the Department of Energy think they have discovered a mysterious new form of energy called "dark energy" that is actually causing the universe to grow.


PS.6, Forms of Energy and Energy Conversions

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PS.6, Forms of Energy and Energy Conversions

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PS.7 The student will investigate and understand temperature scales, heat, and thermal energy transfer. Key

concepts include a) Celsius and Kelvin temperature scales and absolute zero; b) phase change, freezing point, melting point, boiling point, vaporization, and condensation; c) conduction, convection, and radiation; and d) applications of thermal energy transfer.


Heat and temperature are not the same thing. Heat is the transfer of thermal energy between substances of different temperature. As thermal energy is added, the temperature of a substance increases.

Temperature is a measure of the average kinetic energy of the molecules of a substance. Increased temperature means greater average kinetic energy of the molecules in the substance being measured, and most substances expand when heated. The temperature of absolute zero (–273oC/0 K) is the theoretical point at which molecular motion stops.

Atoms and molecules are perpetually in motion.

The transfer of thermal energy occurs in three ways: by conduction, by convection, and by radiation.


CONDUCTION CONVECTION RADIATION

Heat is transferred from one

particle of matter to another by

direct contact.

Heat is transferred through a

liquid or gas by the movement of

particles of matter as currents.

Heat is transferred through

matter and space as

electromagnetic waves.

Particles resonate and collide

with one another transferring

heat.

Particles spread apart and rise.

Example:

A spoon placed a hot bowl of

soup

Example:

Boiling water in a pot or heating

and cooling systems

Example:

Warmth from a campfire or the

sun warming the Earth’s surface

As thermal energy is added to or taken away from a system, the temperature does not always change. There is no change in temperature during a phase change (freezing, melting, condensing, evaporating, boiling, and vaporizing) as this energy is being used to make or break bonds between molecules.

Phase changes occur when heat is subtracted or added to matter.

Heat added to a solid changes the solid to a liquid by melting. Heat added to a liquid changes the liquid to a gas by boiling/vaporization/evaporation. Heat subtracted from a gas changes the gas to a liquid by condensation. Heat subtracted from a liquid changes the liquid to a solid by freezing. Heat subtracted from a solid such as dry ice changes to a gas by sublimation.


PS.7 Temperature and Heat/Heat Transfer

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PS.8 The student will investigate and understand the characteristics of sound waves. Key concepts include a) wavelength, frequency, speed, amplitude, rarefaction, and compression; b) resonance; c) the nature of compression waves; and d) technological applications of sound.


Sound is produced by vibrations and is a type of mechanical energy. Sound travels in compression waves and at a speed much slower than light. It needs a medium (solid, liquid, or gas) in which to travel. In a compression wave, matter vibrates in the same direction in which the wave travels.

The longitudinal wave is often referred to as a compression wave. It is always mechanical because it results from successive compressions (state of maximum density and pressure) and

rarefactions (state of minimum density and pressure) of the medium. Sound waves typify this form of wave

motion.

All waves exhibit certain characteristics: wavelength, frequency, and amplitude. As wavelength increases, frequency decreases.

The shorter the wavelength is the greater the frequency. The higher the crest is from the rest position, the

greater the amplitude. The greater the amplitude the more energy a wave has. In sound, the greater the

frequency is the higher the pitch and the lower the frequency is the lower the pitch. The greater the amplitude

is the louder the sound and the smaller the amplitude is the softer the sound.


The speed of sound depends on two things: the medium through which the waves travel and the temperature of the medium.

Resonance is the tendency of a system to vibrate at maximum amplitude at certain frequencies. There are two kinds of waves:

Longitudinal:

A wave in which particles in the medium are vibrating in the same direction that the wave travels, e.g. sound waves, toy slinky waves.

Transverse :

A wave in which particles in the medium are vibrating in the perpendicular direction that the wave travels, e.g. water waves, light waves, and electromagnetic waves.

A compression (longitudinal) wave consists of a repeating pattern of compressions and rarefactions. Wavelength is measured as the distance from one compression to the next compression or the distance from one rarefaction to the next rarefaction.


Reflection and interference patterns are used in ultrasonic technology, including sonar and medical diagnosis.

A sound wave generator, called a sonar transducer, is located below the waterline of the attacking ship. It transmits sound waves which reflect back to the ship after hitting an underwater object. By measuring the time required for the sound waves to reach the target and return, it is possible to determine the range; bearing is the direction from which the waves were reflected.

Doctors use a hand-held transducer to emit the sound waves. The returning wave which is reflected from the interfaces between different tissues in the body is detected and used to form an image.


PS.8, Characteristics of Waves

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PS.9 The student will investigate and understand the characteristics of transverse waves. Key concepts include

a) wavelength, frequency, speed, amplitude, crest, and trough; b) the wave behavior of light; c) images formed by lenses and mirrors; d) the electromagnetic spectrum; and e) technological applications of light.

Visible light is a form of radiant energy that moves in transverse waves.

There is an inverse relationship between frequency and wavelength. A wave with a higher frequency has a shorter wavelength. A wave with a lower frequency has a longer wavelength.

Electromagnetic waves are arranged on the electromagnetic spectrum by wavelength. All types of electromagnetic radiation travel at the speed of light, but differ in wavelength. The electromagnetic spectrum includes gamma rays, X-rays, ultraviolet, visible light, infrared, and radio and microwaves.

All transverse waves exhibit certain characteristics: wavelength, crest, trough, frequency, and amplitude. As wavelength increases, frequency decreases. There is an inverse relationship between frequency and wavelength.


Radiant energy travels in straight lines until it strikes an object where it can be reflected, absorbed, or transmitted. As visible light travels through different media, it undergoes a change in speed that may result in refraction. Reflection of Light

Law of Reflection: the angle of incidence is equal to the angle of reflection

Refraction of Light Transmission of Light

Radio waves are the lowest energy waves and have the longest wavelength and the lowest frequency. Gamma rays are the highest energy waves and have the shortest wavelength and the highest frequency. Visible light lies in between and makes up only a small portion of the electromagnetic spectrum.

Visible light consists of the colors red, orange, yellow, green, blue, indigo, and violet. All the colors of visible

light combine to form white light.

Plane, concave, and convex mirrors all reflect light. Convex mirrors diverge light and produce a smaller, upright image. Concave mirrors converge light and produce an upright, magnified image if close and an inverted, smaller image if far away.

Concave and convex lenses refract light. Concave lenses converge light. Convex lenses diverge light.


Light can be reflected and refracted by mirrors and lenses to form virtual and real images.

A convex lens makes objects look larger and farther away. Convex lenses correct farsightedness. A concave lens

makes objects look smaller and closer.

Technology uses mirrors and lenses in cameras, telescopes, fiber optics, and periscopes.


Diffraction is when light waves strike an obstacle and new waves are produced.

Interference takes place when two or more waves overlap and combine as a result of diffraction.


PS.9,Technological Applications of Light

26

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PS.10 The student will investigate and understand the scientific principles of work, force, and motion.

Key concepts include a) speed, velocity, and acceleration; b) Newton’s laws of motion; c) work, force, mechanical advantage, efficiency, and power; and d) technological applications of work, force, and motion.

make measurements to calculate the speed of a moving object. apply the concepts of speed, velocity, and acceleration when describing motion. differentiate between mass and weight. identify situations that illustrate each Law of Motion. explain how force, mass, and acceleration are related. apply the concept of mechanical advantage to test and explain how a machine makes work

easier. make measurements to calculate the work done on an object. make measurements to calculate the power of an object. solve basic problems given the following formulas:

Speed = distance/time (s = d/t) Force = mass × acceleration (F = ma) Work = force × distance (W = Fd) Power = work/time (P = W/t).

explain how the concepts of work, force, and motion apply to everyday


Acceleration is the change in velocity per unit of time. An object moving with constant velocity has no acceleration. A decrease in velocity is negative acceleration or deceleration. A distance-time graph for acceleration is always a curve. Objects moving with circular motion are constantly accelerating because direction (and hence velocity) is constantly changing.

Distance/Time Graph: The graph depicts a curve showing the distance traveled at different time intervals.

Newton’s three laws of motion describe the motion of all common objects. Newton's first law states that every object remains at rest or in uniform motion in a straight line unless

compelled to change its state by the action of an external force. This is normally taken as the definition of

inertia. The key point here is that if there is no net force acting on an object (if all the external forces

cancel each other out) then the object maintains a constant velocity.

http://wright.nasa.gov/airplane/newton1w.html


In the diagram: Newton’s first law is demonstrated with a ball. It will remain where it is unless it is acted upon by a force. In other words, it will remain not in motion or in motion until it is moved. *Another example of the first law would be a seat belt (restraining device), the seat belt will hold you in place while the car is in motion. If you take the seat belt off your body will continually be in motion as the car is in motion.

Newton’s three laws of motion describe the motion of all common objects. (continued)

The second law explains how the velocity changes. The law defines a force to be equal to change in momentum (mass times velocity) per change in time. For an object with a constant mass, the second law can be more easily expressed as the product of an object's mass and it's acceleration.

F = m x a

Acceleration is the change in velocity with change in time. For a constant external applied force, the acceleration is inversely proportional to the mass. For the same force, a lighter object has a higher acceleration than a heavy object. A force causes a change in velocity; and likewise, a change in velocity generates a force. The equation works both ways. Newton developed the calculus of mathematics. The "changes" expressed in the second law are accurately defined in differential forms. Calculus can also be used to determine the velocity and location variations experienced by an object subjected to an external force.

http://wright.nasa.gov/airplane/newton2.html


*In the diagram above: Newton’s second law in demonstrated by the golfer applying force to the ball. The ball has a small mass, so it will accelerate (move faster) over a longer distance. *If an object contains a large amount of mass then it will need a bigger force in order to make it accelerate. *Another example of the second law is using remote controlled cars (powered vehicles), the bigger (containing more mass) they are, the longer it takes for them to accelerate and the smaller (containing less mass) they are then they will take less force to accelerate.

Newton’s three laws of motion describe the motion of all common objects.(Continued)

The third law states that for every action (force) in nature there is an equal and opposite reaction.

http://wright.nasa.gov/airplane/newton3.html


Most rockets produce a thrust of burning gases from the combustion of chemical propellants (solid or liquid forms) which are ejected from the rocket through the exhaust nozzle. The rocket moves forward due to the opposed reaction from the exhaust blast, not the exhaust itself. The greater the speed of the blast, the greater the reaction is against the rocket, which in turn produces a greater overall velocity. The exhaust produces a force against the air, thus propelling it forward. Since the exhaust blast does not require anything to push against, the rocket can operate with greater efficiency in space.

Mass and weight are not equivalent. Mass is the amount of matter in a given substance. Weight is a measure of the force due to gravity acting on a mass. Weight is measured in newtons.

The weight of an object is the result of the gravitational force between the object and the Earth.

The greater the mass of an object, the greater its weight. An elephant has more mass than a

mouse, so it has a greater weight. Weight is measured in newtons or N. Notice that the unit

of weight is the same as the unit of force.

An object's weight can change if it goes into space or to another planet. This is because gravity

may be weaker or stronger there than it is on the Earth.


**Remember that mass is measured in kilograms, kg, and weight is measured in newtons, N. The mass of an

object stays the same wherever it is, but the weight of the same object can change. This happens if the object

goes somewhere where gravity is stronger or weaker, such as into space.

The Moon has less mass than the Earth, so its gravity is less than the Earth's gravity. This means that objects

weigh less on the Moon than they do on the Earth. For example, a 120 kg astronaut weighs 1200 N on Earth

(remember to times kg by 10 to get N). The same astronaut would weigh just 200 N on the Moon, because the

Moon's gravity is one sixth the Earth's gravity. Note that the astronaut's mass stays the same.

A force is a push or pull. Force is measured in newtons. Force can cause objects to move, stop moving, change

speed, or change direction. Speed is the change in position of an object per unit of time. Velocity may have a

positive or a negative value depending on the direction of the change in position, whereas speed always has a

positive value and is non-directional.

Work is done when an object is moved through a distance in the direction of the applied force.

** Remember that work is measured in units of joules (J).

•A simple machine is a device that makes work easier. Simple machines have different purposes: to change the effort needed (mechanical advantage), to change the direction or distance through which the force is

The weight of an object changes if the strength of

gravity changes.


applied, to change the speed at which the resistance moves, or a combination of these. Due to friction, the work put into a machine is always greater than the work output. The ratio of work output to work input is called efficiency.

A Table of Simple Machines

Inclined Plane A plane is a flat surface. For example, a smooth board is a plane. Now, if the plane is lying flat on the ground, it isn't likely to help you do work. However, when that plane is inclined, or slanted, it can help you move objects across distances. And, that's work! A common inclined plane is a ramp. Lifting a heavy box onto a loading dock is much easier if you slide the box up a ramp--a simple machine.

Wedge Instead of using the smooth side of the inclined plane, you can also use the pointed edges to do other kinds of work. For example, you can use the edge to push things apart. Then, the inclined plane is a wedge. So, a wedge is actually a kind of inclined plane. An axe-blade is a wedge. Think of the edge of the blade. It's the edge of a smooth slanted surface. That's a wedge! Want to know more?

Screw Now, take an inclined plane and wrap it around a cylinder. Its sharp edge becomes another simple tool: the screw. Put a metal screw beside a ramp and it's kind of hard to see the similarities, but the screw is actually just another kind of inclined plane. Every turn of a metal screw helps you move a piece of metal through a wooden space. And, that's how we build things!

Lever Try pulling a really stubborn weed out of the ground. You know, a deep, persistent weed that seems to have taken over your flowerbed. Using just your bare hands, it might be difficult or even painful. With a tool, like a hand shovel, however, you should win the battle. Any tool that pries something loose is a lever. A lever is an arm that "pivots" (or turns) against a "fulcrum" (or point). Think of the claw end of a hammer that you use to pry nails loose. It's a lever. It's a curved arm that rests against a point on a surface. As you rotate the curved arm, it pries the nail loose from the surface. And that's hard work!

Wheel and Axle The rotation of the lever against a point pries objects loose. That rotation motion can also do other kinds of work. Another kind of lever, the wheel and axle, moves objects across distances. The wheel, the round end, turns the axle, the cylindrical post, causing movement. On a wagon, for example, the bucket rests on top of the axle. As the wheel rotates the axle, the wagon moves. Now, place your pet dog in the bucket, and you can easily move him around the yard. On a truck, for example, the cargo hold rests on top of several axles. As the wheels rotate the axles, the truck moves.

Pulley Instead of an axle, the wheel could also rotate a rope or cord. This variation of the wheel and axle is the pulley. In a pulley, a cord wraps around a wheel. As the wheel rotates, the cord moves in either direction. Now, attach a hook to the cord, and you can use the wheel's rotation to raise and lower objects. On a flagpole, for example, a rope is attached to a pulley. On the rope, there are usually two hooks. The cord rotates around the pulley and lowers the hooks where you can attach the flag. Then, rotate the cord and the flag raises high on the pole.

If two or more simple machines work together as one, they form a compound machine. Most of the

machines we use today are compound machines, created by combining several simple machines.


Compound Machines: A compound machine consists of two or more simple machines put together. In fact, most machines are compound machines. Compound machines can do more difficult jobs than simple machines alone. Their mechanical advantage is far greater, too. Some examples are a pair of scissors and a bicycle.

In science, work is defined as a force acting on an object to move it across a distance. Pushing, pulling, and lifting are common forms of work. Furniture movers do work when they move boxes. Gardeners do work when they pull weeds. Children do work when they go up and down on a see-saw. Machines make their work easier. The furniture movers use a ramp to slide boxes into a truck. The gardeners use a hand shovel to help break through the weeds. The children use a see-saw to go up and down. The ramp, the shovel, and the see-saw are simple machines.

More Compound Machines


Mechanical Advantage = Output Force Input Force

The force you put on a machine is the input force. The force that is made by the machine is the output force. The mechanical advantage of a machine is the ratio of the output force to the input force.

Mathematical formulas are used to calculate speed, force, work, and power.

OR

Unit: watt

OR

Unit: Newton

OR

Unit: Joule

OR

Unit: m/s


PS.10 Principles and Technological Applications of Work, Force, and Motion


PS.11 The student will investigate and understand basic principles of electricity and magnetism. Key concepts include a) static electricity, current electricity, and circuits; b) relationship between a magnetic field and an electric current; c) electromagnets, motors, and generators and their uses; and d) conductors, semiconductors, and insulators.


Several factors affect how much electricity can flow through a system. Resistance is a property of matter that affects the flow of electricity. Some substances have more resistance than others.

Friction can cause electrons to be transferred from one object to another. These static electrical charges can build up on an object and be discharged slowly or rapidly. This is often called static electricity.

For example: Rubbing a balloon against

your hair (friction) causes an electric buildup.

The buildup causes your hair to stand

up on top of your head! Static Electricity!

CURRENT ELECTRICITY: Current electricity is when the electrons are controlled by moving along a path together. The path is usually a conductor of electricity. A copper wire can move electricity from a power plant to a house.


CIRCUITS: Open Circuit: In order for electricity to flow, there must be a continuous, conducting path between the negative "pole" and the positive pole of the power source (battery, electricity outlet, etc.). A broken wire or an "open" (off) switch both leave gaps in a circuit preventing electrons from traveling from one side of the power source to the other. Thus, electrons will not flow.

Closed Circuit A closed (on) switch means that the circuit through the switch is connected. Thus, you have a closed circuit (a circuit with no gaps in it). Current flows from the positive side of the power source (for example, the battery) to the loads (lightbulbs, fans, and etc.) wired into the circuit and back to the negative side of the power source.

Electricity is related to magnetism. Magnetic fields can produce electrical current in conductors. Electricity can produce a magnetic field and cause iron and steel objects to act like magnets.

What is a magnetic field? Typically, most people have been exposed to the phenomena created when you lay a bar magnet on a table, place a piece of glass over it and sprinkle iron filings on the glass. What turns up is a pattern of lines formed by the iron filings going from one end of the magnet to the other. Although a magnetic field isn't truly comprised of lines, the iron filings give a good visual representation of the bar magnet's magnetic field.

Open Circuit (the switch is OFF)

Closed Circuit (the switch is ON)


Electromagnets are temporary magnets that lose their magnetism when the electric current is removed. Both a motor and a generator have magnets (or electromagnets) and a coil of wire that creates another magnetic field.

A generator is a device that converts mechanical energy into electrical energy. Most of the electrical energy we use comes from generators. Electric motors convert electrical energy into mechanical energy that is used to do work. Examples of motors include those in many household appliances, such as blenders and washing machines.

GENERATOR: Move a wire next to a magnet ====> electricity comes out

MOTOR: What if we reverse the idea of how a generator works? electricity goes in ====> wire moves when next to a magnet We have just invented a simple motor!

Reminder: Adding voltage can increase

the power of electromagnets.

Additionally, the more wire that is

wrapped around the nail the stronger

the magnetism becomes.


A conductor is a material that transfers an electric current well. An insulator is material that does not transfer an electric current. A semiconductor is in-between a conductor and an insulator.

Conductors-

*Electricity Flows Well

Examples: Copper, Steel, Aluminum

Insulators

*Electricity Does Not Flow

Examples: Wood, Plastic, Rubber, Glass, Styrofoam

Semiconductors

*Has properties of both conductors and insulators

Examples:

Silicon

Diodes-LED lights

•The diode is a semiconductor device that acts like a one way valve to control the flow of electricity in electrical circuits. Solar cells are made of semiconductor diodes that produce direct current (DC) when visible light, infrared light (IR), or ultraviolet (UV) energy strikes them. Light emitting diodes (LED) emit visible light or infrared radiation when current passes through them. An example is the transmitter in an infrared TV remote or the lighting course behind the screen in an LED TV or notebook computer screen.

Transistors are semiconductor devices made from silicon, and other semiconductors. They are used to amplify electrical signals (in stereos, radios, etc.) or to act like a light switch turning the flow of electricity on and off.


PS.11, Principles of Electricity and Magnetism

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SOL PS.1

hypothesis A possible explanation or answer to a question

independent variable A manipulated/changed factor which is indicated on the X

axis of a graph

dependent variable Measurable/response to change factor which is indicated on

the Y axis

constants A factor that does not change in a specific inquiry/lab

controls A factor of comparison in a scientific inquiry that is not

tested

SOL PS.2

matter Anything that has volume and mass

particle theory of matter

All matter is composed of tiny particles called atoms.

element A pure substance that cannot be separated or broken down

into simpler substances by physical or chemical means

compound A pure substance composed of two or more elements that

are chemically combined

mixture A combination of two or more substances that are not

chemically combined


solvent The substance in which a solute is dissolved to form a

solution

ph scale A measure of hydronium ion concentration in a solution

base Any compound that increases the number of hydroxide ions

when dissolved in water

salt An ionic compound formed from the positive ion of a base

and the negative ion of an acid

acid Any compound that increases the number of hydrogen ions

when dissolved in water

solute

The substance that is dissolved to form a solution

inorganic compound A compound that does not contain carbon

organic compound A compound that contains carbon

density The amount of matter in a given space; mass per unit

volume

physical property A property of matter that can be observed or measured

without changing the identity of the matter


chemical property A property of matter that describes a substance based on its

ability to change into a new substance with different properties

SOL PS.3

atom The smallest particle into which an element can be divided

and still be the same substance.

proton The positively charged particle of the nucleus

neutron The particles of the that have no charge

electron The negatively charged particles found in all atoms

quantum mechanics A theory of the mechanics of atoms, molecules, and other

physical systems that are subject to the uncertainty principle

electron cloud The regions inside an atom where electrons are likely to be

found

SOL PS.4

periodic table of elements

A table of elements arranged by atomic number that shows patterns in their properties

periods a row of elements on the periodic table

ion Charged particles that form during chemical changes


isotope Atoms that have the same number of protons but have

different numbers of neutrons

metals Elements that are shiny and good conductors of heat and

electricity

nonmetals Elements that are dull and poor conductors of heat and

electricity

compound A pure substance composed of two or more elements that

are chemically combined

atomic number The number of protons in the nucleus of an atom

atomic mass The weighted average of the masses of all the naturally

occurring isotopes of an element

ionic bond The force of attraction between oppositely charged ions

covalent bond The force of attraction between the nuclei of atoms and the

electrons shared by the atoms

metalloids Elements that have properties of both metals and

nonmetals

element A pure substance that cannot separated or broken down

into simpler substances by physical or chemical means

valence electrons The electrons in the outermost energy level of an atom


family A column of elements on the periodic table

SOL PS.5

physical change A change that affects one or more physical properties of a

substance. (Many physical changes are easy to undo)

Law of Conservation of Matter (mass)

The law that states that mass is neither created nor destroyed in ordinary chemical and physical changes.

Law of Conservation of

Energy

The law that states that energy is neither created nor destroyed.

endothermic energy

A physical or a chemical change in which energy is

absorbed.

exothermic energy

A physical or a chemical change in which energy is released or removed.

chemical equation

A shorthand description of a chemical reaction using chemical formulas and symbols.

SOL PS.6

potential energy The energy of position or shape.

kinetic energy The energy of motion.

mechanical energy The total energy of motion and position of an object.


chemical energy The energy of a compound that changes as its atoms are

rearranged to form a new compound.

electrical energy The energy of electric charges.

light energy The energy produced by the vibrations of electrically

charged particles.

heat energy The heat energy of a substance is determined by how active

its atoms and molecules are.

sound The energy caused by an object’s vibrations.

energy transformation The process of changing one form of energy into another.

SOL PS.7

convection The transfer of thermal energy by the movement of a liquid

or a gas

radiation The transfer of energy through matter or space as an

electromagnetic wave

heat transfer the process whereby heat moves from one body or

substance to another by radiation, conduction, or convection

Celsius temperature scale

The temperature scale used by most scientist


Kelvin temperature scale

The SI unit for temperature

absolute zero Lowest temperature on the Kelvin scale

heat The transfer of energy between objects that are at different

temperatures

temperature Measure of the average kinetic energy of the particles in an

object

phase change The conversion of a substance from one physical form to

another

freezing point The change of state from a solid to a liquid

melting point The temperature at which the substance changes from a

solid to a liquid

boiling point The temperature at which a liquid boils

vaporization The change of state from a liquid to a gas

condensation The change of state from a gas to a liquid

conduction The transfer of thermal energy

through direct contact


SOL PS.8

wavelength The distance between one point on a wave and the

corresponding point on an adjacent wave in a series of waves.

frequency The number of waves produced in a given amount of time.

speed The rate at which an object moves.

amplitude The maximum distance a wave vibrates from its rest

position.

resonance What occurs when an object vibrating at or near a

resonant frequency of a second object causes the second object to vibrate.

longitudinal wave A wave in which the particles of the medium vibrate back

and forth along the path that the wave travels.

medium A substance through which a wave can travel.

compression A region of higher density or pressure in a wave.

rarefaction A region of lower density or pressure in a wave.


SOL PS.9

reflection the bouncing back of a wave after it strikes a barrier

refraction the bending of a wave as it passes at an angle form one

medium to another

diffraction the bending of waves around a barrier or through an

opening

interference A wave interaction that occurs when two or more waves

overlap

electromagnetic spectrum

The entire range of electromagnetic waves

electromagnetic radiation

Radiation consisting of electromagnetic waves

transverse A wave in which the particles of the waves medium

vibrate perpendicular to the direction the wave is traveling

gamma waves Electromagnetic waves with no mass and high energy


x-rays Electromagnetic waves with high energy that are

between ultraviolet and gamma rays

ultraviolet Electromagnetic waves that are between visible light

and x-rays on the spectrum

visible light The narrow range of wavelengths and frequencies on

the spectrum that humans can see

infrared Electromagnetic waves that are between microwaves

and visible light on the spectrum

radio waves Electromagnetic waves with long wavelengths and low

frequencies

microwaves

Electromagnetic waves between radio waves and infrared waves on the spectrum

SOL PS.10

speed The rate at which an object moves.

velocity The speed of an object in a particular direction.

acceleration The rate at which velocity changes.

Newton’s Laws of Motion

Three physical laws which provide relationships between the forces acting on an object and the motion of an object.

http://en.wikipedia.org/wiki/Physical_law

http://en.wikipedia.org/wiki/Direct_relationship

http://en.wikipedia.org/wiki/Force

http://en.wikipedia.org/wiki/Motion_%28physics%29


work The action that results when a force causes an object to

move in the direction of the force.

force A push or pull.

mechanical advantage A number that tells how many times a machine multiplies

force.

efficiency The percentage of the input work done on a machine that

the machine can return in output work.

power The rate at which work is done.

mass The amount of matter that something is made of.

weight A measure of the gravitational force exerted on an object,

usually by the Earth.

simple machines The six machines from which all other machines are constructed-(lever, an inclined plane, wedge, screw,

wheel and axle, pulley).

compound machine A machine that is made of two or more simple machines.


SOL PS.11

static electricity The buildup of electric charges on an object.

current electricity A constant flow of electrons.

series circuit A circuit in which all parts are connected in a single loop.

parallel circuit A circuit in which different loads are on separate branches.

magnetic field The region around a magnet in which magnetic forces can

act.

electric current A continuous flow of electric charge.

motor A device that changes electrical energy into kinetic energy.


generator A device that uses electromagnetic induction to convert

kinetic energy into electrical energy.

voltage The difference in energy per unit charge as a charge moves

between two points in an electric circuit.

resistance The opposition to the flow of electric charge.

current A continuous flow of charge caused by the motion of

electrons. The rate at which a charge passes a given point.

direct current Electric current in which the charges always flow in the

same direction.

electromagnet A magnet that consists of a solenoid wrapped around an

iron core.

conductor A material in which charges can move easily.

alternating current Electric current in which the charges continually switch from flowing in one direction to flowing in the reverse

direction.

insulator A material in which charges cannot easily move.

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Content Review Notes for Parents and Students