Science Form1- Chp1

8/8/2019 Science Form1- Chp1

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Chapter1: Introduction to Science

What is Science?- Science is thesystematic study of nature to understand how it affects our lives and environment.

(The knowledge of nature phenomena and environment.)

Natural Phenomena-Nature Phenomena are occurrences in nature.

Example:

-Northern light - Formation of rainbow

- Grow of baby - Lightning

Science is important in our daily life, it made our life more comfortable.For example, Scientific discoveries and knowledge will help our to improve our standard of living. As,

internet. It helps us more easily to find up the news on global.

A Science Laboratory.

- Scientific experiment are usually carry out in laboratory.- However, most of the chemical used in experiment are poisonous.

- To prevent injury to oneself and other, one needs to know the General Rules and SafetyPrecautions in

laboratory.


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Common laboratory apparatus- Apparatus is used to carry out experiments and made accurate measurement or observation.

Crucible Evaporating dish Displacement can

-Used in heating solid directly - To allow a liquid to evaporate - For a displaced liquid to flowover a flame. from a solution. Out through the spout.

Filter funnel Bell jar Gas Jar

-To separate an insoluble solid - To separate an experiment -To collect gas.from a liquid with the use of a set up from outside environment.piece of filter paper.

Boiling tube Beaker Test tube

-To contain or heat small -To contain chemical or collect -To contain small amount of

amount of substance. liquid. liquid.

Conical flask Flat- bottomed flask Round- bottomed flask

-To contain chemical or -To contain chemicals used in -To contain chemicals used in

collect liquid. preparing gases when no preparing gases when heating.

heating.

Meter rule Beam balance Stop Watch

-To measure length -To measure mass. To measure time.


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Burette Measuring cylinder Pipette

-To measure a volume to -To measure a volume of -To accurately measure a

an accuracy of 1cm an accuracy of 1cm specific volume of liquid.

Tripod stand Bunsen burner Retort stand-To support the apparatus -To provide a flame for -To hold the apparatus during

during heating. The wire heating substance. experiment.

gauze serves to conduct

the excess away.

Thermometer Test-tube rack Test-tube holder

-To measure temperature. To hold test tube. to hold test tube during heating

The Use of Bunsen Burner-Bunsen burner is used in a laboratory to heat substances.


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-Thesize of the air hole will determine the type of the flame.

1. When the air hole is closed, a luminous yellow flame produced. This flame produces a lot of soot

because the gas does not burn completely. It not suitable for heating.

2. When the air hole is opened, the flame change to non-luminous blue flame. This flame is very hot

because the gas burn completely. Itsuitable for heating.

Hazard symbols- Some substances in the laboratory are dangerous and harmful to our health.- Hazard warning symbols are placed on the labels of bottles or containers to warn users of the

hazardous nature of the content.

Symbol Example Explanation

Explosive- Potassium, sodium,

concentrated acid &

alkalis, mixture ofhydrogen and air.

- Explodes easily when mixed with other

substances.

Corrosive- Concentrated acid &

alkalis, bromine

- Causes damage to the skin or eyes upon

contact.

Flammable- Petrol, ethanol,kerosene

- Catches fire and burn easily

Irritant- alcohol, chloroform,

Ammonia

- Irritates eyes, skin and respiratory system.

Toxic / Poisonous

- Mercury, sodiumcyanide, benzene

- Causes death or harm to the body ifswallowed, inhaled or absorbed through the

skin

Table1.1: Hazard Warning Symbols.


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The Steps in a Scientific InvestigationWhat is Scientific investigation?

- Scientists acquire scientific knowledge by carrying out scientific investigation.

- A scientific investigation is asystematic method of studying a problem to find out causes ofnature phenomena.

- The flow chart in photo1.1 shows the sequence ofstep in a scientific investigation.

Photo1.1: Scientific Investigation

Sample of report: The relationship between the length of a pendulum and the period of oscillation.

Experiment1: Investigation the relationship between the length of a pendulum and the period of

oscillation.

Problem statement: How does the length of a pendulum affect the period of oscillation.

Hypothesis: The longer the length of the pendulum, the longer the time oscillation.

Variable: (a) Manipulated Variable: The length of the pendulum.

(b) Responding Variable : The times of oscillation.

(c) Constant Variable : The mass/type of pendulum bob.

Figure1


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Procedure:

1. A 20cm long simple pendulum is set up as show in above figure.

2. The pendulum is pulled to one side and then released.3. The time taken for the pendulum to make 10 swings is recorded. The steps is repeated to obtain a

second reading.

4. Steps 2 and 3 are repeated by using pendulum length of 40cm, 60cm, and 80cm.5. The result are recorded in table below.

Results:

Length of

pendulum. (cm)

Time taken for 10 swings (s) Time taken for

one swings (s)First Second Average

20 11.9 12.1 12.0 1.2

40 13.9 14.1 14.0 1.4

60 15.9 16.1 16.0 1.6

80 17.9 18.1 18.0 1.8

Discussion:

The data from table 1 are the results of the investigation. An interpretation of these data will lead to an

inferences that the time taken for pendulum to made one swings increases as the length og pendulumincreases.

Conclusion:

The longer the pendulum, the longer the period of the oscillation. The hypothesis is accepted.

Physical Quantities and their Units-A physical quantity is a quantity that can be measures. There are five main group of physical quantitythat we used frequently.

Physical Quantity SI Units

Name Symbols

Length metre m

Mass kilograms kg

Temperature seconds s

Time kelvin K

Electric Current ampere A

The use of Measuring Tools

-Measurement is a skill required in collecting data in a scientific investigation.

1.Measurement of lengths

-Length is a distance between two point .

-A length of a object can be measured using a metre ruler or a measuring tape.-The scale on the metre rule is in centimeters (cm) and millimeters (mm). It measure lengths to an

accuracy of 0.1cm.

10 millimeters (mm) = 1 centimeters (cm)

100centimeters (cm) = 1 metre (m)


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-Measuring the length of an object.

(a) The rule is placed at the side of the object to be measured.

(b) To take a more accurate reading, the eye needs to be vertically above the mark on the ruler(position B), as shown in Figure1.2.

(c) If the eye is at A or C, the reading is not accurate. This kind of error is know asparallax error.

Figure1.2

-Measuring the length of a curve line.

(a) The length of a curve line can be measured by opisometer and a metre rule. The opisometer istraced along the curve and later wheeled backward along the metre rule to get the measurement.

Figure1.3: An opisometer

-Measuring the diameter of an object.(a) The diameters of cylinders can be measured more accurately using calipers and a ruler. A ruler

cannot measure the diameter of an object accurately.

Figure1.4a: Measuring the external diameter. Figure1.4b: Measuring the internal diameter

2. Measuring of areas- The areas of an object is the size of the surface of an object.

- The SI unit of areas is square metres (m).

- Large areas can be measured in square kilometers (km), centimeters (cm), and millimeters (mm).- The areas of object with regular shapes, we may calculated by using mathematical formulae.

- If the areas of object are irregular shapes, we can estimated by using graph paper.

Figure1.5


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3. Measuring of volume

- The volume of an object is a measure of the space occupied by the object.

- The SI units of volume is cubic metres (m).- Large areas can be measured in square kilometers (km), centimeters (cm), and millimeters (mm).

- All the units can be measure the volume of liquids. However, the volumes of liquid usually measured

in metric units, as milliliters (m ) and liters ().

- Volume of liquids- Volume of liquids can be measured by using a measuring cylinder, pipette or a burette.

Figure1.6: Correct reading volume of water , Correct reading of mercury.

-Volume of Solid.

- The volume of regular and irregular solids can be measured by using water displacement method.

Figure1.7: Measuring the volumes of regular and irregular solids.

- The eureka can (displacement can) is also used to measure the volumes of regular and irregular solidswhich are too big for a measuring cylinder.

Figure1.8: Measuring the volume of an irregular solid with a eureka can.


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Weight and Mass

Weight

- Weight of an object is a result of the pull of earths gravity on the object.

- The weight of an object changes from one place to another, depending on the force of gravity

forces.- Weight of an object can be measured with a spring balance or a compression balance.

- The SI unit of weight is Newton (N).Mass

- Mass of an object is the quantity of matter contained in the object.- The mass of an object doesnt change because the quantity of matter it contain is the same

wherever the object is.

- Beam balances are used as they give accurate measurement of mass.

Differences between mass and weight.

- Weight and mass are two different quantities.

Weight Differences Mass

Force of gravity that acts onthe object Definition Quantity of matter in an object

Weight of an object changes

from places to places

Value Mass of an object is constant at all

places

Newton (N) SI units Kilograms (kg)

Spring balance, compression

balance

Measuring

Instrument

Beam balance, lever balance,

electronic balance

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Science Form1- Chp1