Section 3:
Measurement
Why do scientists use a standard measurement system?
What are the SI units of measurement for length, mass, volume,
density, time, and temperature?
A Standard Measurement
System

Using SI as the standard system of measurement allows
scientists to compare data and communicate with each other
about their results. SI units- based on multiples of 10.
Length

The basic unit of length in SI is the meter (m).
Mass

The SI unit of mass is the kilogram. Mass refers to
the amount of matter an object contains.
Weight

Weight refers to the measure of the force of gravity
on an object.

Less gravity, less weight!

Weight is measured in Newtons (we use pounds in
USA)
Volume

Volume is the amount of space matter takes up

The SI unit of volume is the cubic meter (m3).
Volume of a regular solid is measured by multiplying
length x width x height
Volume
•
Volume of irregular solids must be measured by
water displacement
Density


The SI unit for density is kilogram per cubic meter or
kg/m3

Density =
Mass
Volume
Density

Because density is actually
made up of two other
measurements–mass and
volume–an object’s density is
expressed as a combination of
two units. The density of a
substance stays the same no
matter how large or small a
sample of the substance is.
Time

The SI unit of time is seconds. Some timepieces can
measure within one one hundredth of a second!
Temperature

The SI unit for temperature is Celsius or Kelvin scale

0 K is called absolute zero and is equal to -273C
Temperature
Scientists use the Celsius and Kelvin scales to
measure temperature. The Kelvin (K) is the SI
unit of temperature. We will use Celsius!

Water freezes at 0 degrees Celsius and boils at 100
End of Section:
Measurement