International System of Units (SI):

• standard system of measurements based on multiples of ten

Why do we use a system of measurements?

• In science we need to have accurate and precise communication

• A measurement of “1” means nothing UNLESS it has units.

A Measurement Has Three Parts 1)The numerical value which

tells how much

2) The unit, which tells us what the measurements are in

3)The type of measurement 25 cmVALUE

UNIT

MEASURING LENGTH

1. Liquid Volume: the amount of space a liquid takes up

- Unit of measurement

is liter (L)

- Scientific tool use to measure liquid volume is a graduated cylinder

- Example: 1 L = the volume of a medium water bottle

Read at the meniscus, lowest point of the liquid

Finding the Volume of a Solid…

A. Regular Shaped Objects (cube) Volume = L X W x H

Volume = cm x cm x cm

Volume = cm3

HEIGH

LENGTH T

WIDTH

Example: Volume = L x W x HVolume =3.80 cm x 2.60 cm x 3.80 cmVolume = 37.54 cm3

B. Volume - Irregular Shaped Object…

• Fill a graduated cylinder to a certain level with water.

• Next, put the object in see how much the water rises up.

• Then subtract the original level from the second water level to find the volume.• 1 mL = 1 cm3

2. Length: the distance between two points

- Standard (base) unit of measure is meter (m)

- Large distances measured in kilometers (km)

- Smaller distances are measured in centimeters (cm) or millimeters (mm)

- Use metric ruler or meter stick to measure length

- Example: 1m = distance from the floor to the doorknob

3. Mass: the amount of matter in an object • Matter is “anything that takes up

space”

• Unit of measurement is gram (g) • Large measurements are measured in

kilograms (kg)

• 1000 grams = 1 kg

• Scientific tool used to measure mass is a balance

MASS VS WEIGHT Is defined as the force of gravity on the object Measured with spring scale Changes from planet to planet

is the same wherever you are

PAN BEAMS

Zero RIDERS POINTER

Adjustment

Knob

4. Temperature• A measure of the average energy of motion of the

particles of a substance

• The more the particles move the higher the temperature

• The less the particles move the colder the temperature

• Unit of measurement is degrees Celsius ºC

• Water freezes at 0ºC and boils at 100 ºC