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Measurements
In
Science
• A MEASUREMENT includes both a number that identifies how many units there are and a unit of measure.
• Example: 2 cups
• Most scientific studies and experiments use a standard system of metric units called Le Système International d’Unités, or SI for short.
• SI - modern version of the metric system based on a decimal system that uses the number 10 as the base unit.
SI Base Units
• The Meter (m) measures length.
Length
English
inch
foot
yard
Mile
Metric
mm
cm
m
km
The meter can be divided into 100 equal parts called Centimeters (cm).
A millimeter (mm) is smaller than a centimeter. There is 10mm in 1cm.
Long distances are measured in kilometers (1000 m).
How many mm’s are in a meter? 100 cm
X 10 mm
1000 mm
• measure of the gravitational force on an object.
varies with location (ex. Moon).
Metric Unit = Grams (g), milligrams (mg) .
Weight
Mercury Venus Earth Moon Mars
If you weighed 100 lbs…
37.8 90.7 100 16.6 37.9
Jupiter Saturn Uranus Neptune Pluto
236.4 106.4 88.9 112.5 6.7
English
ounce
pound
ton
Metric
Grams
Milligrams
Weight
• amount of matter in an object.
• Depends on the numbers and kind of atoms that make up an object.
• Does not change with an object’s location.
Mass
• The SI unit of mass is the kilogram (kg).
English
pounds
Metric
milligrams
grams
Kilogram
On earth the spring scale reads 100g with an unknown mass attached at the bottom.
To balance the balance scale on the right how many grams would be needed?
If we were to take both scales to the moon, what would the spring scale read (moon has 1/6th the gravity of Earth)? How much mass would be needed to balance the 100g mass on the balance beam? Can you explain your answer? See if you are right by completing the questions below.
Spring Scale
Balance Scale
• amount of space an object takes up.
• For example, an inflated balloon takes up more space than an empty balloon. (A balloon that is blown up has more volume than one that hasn’t been blown up)
Volume
• SI measurements for liquid volumes are usually made in milliliters (mL) or liters (L).
English
drop
tsp
tbsp
Cup
Gallon
Pint
Metric
mL
liter
1 US gallon = 3.78541178 liters
Volume = Length x Width x
Height
Beakers
Erlenmeyer Flasks
Graduated Cylinders
Test Tubes
Volumetric Flasks
Density• Describes the degree of compactness of a substance.
• In other words…how closely are the atoms packed together.
• More atoms in a given space = dense
• Less atoms in a given space = less dense
Which object is more dense?
Which two factors determine Density?
• Mass = a measure of the amount of atoms• Volume = the space that the atoms take up
Mass = gramsVolume = mL or cm3 (1ml = 1 cm3)• Expressed in grams per cubic centimeter
(g/cm3)
calculated by dividing the mass of
an object by its volume
Time is the interval between 2 events and is measured with a watch or clock.
SI unit of time is the second.
Time
Temperature is a measure of the average vibrations of the particles that make up a material. (ex. solid, liquid, & gas)
SI unit for temperature is the Kelvin (K) scale.
Temperature
English
Fahrenheit
Metric
Celsius
Kelvin
1st °C = (°F - 32) / (1.8)
2nd K = °C + 273.15
To calculate Fahrenheit to Kelvin:
Solid = tightly packed, regular pattern, vibrate
(jiggle) but don’t move from place to place
Liquid = close together, no regular arrangement, vibrate,
move about and slide past each other
Gas = well separated, no regular arrangement, vibrate
and move freely at high speeds
• °C x 9/5 + 32 = °F
To calculate Celsius to Fahrenheit:
• (°F - 32) x 5/9 = °C
To calculate Fahrenheit to Celsius: