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: