Mass, Volume & Density

8th Grade Science

What is Mass?

-The amount of matter an object has.

-Unit of measurement = kg or g

-What tool do we use to find mass?

What is Volume?

-The quantity of space an object occupies.

-Unit of measurement = ml or cm3

so which one do you use when?

-What tools can we use to find volume?

Finding Volume of a Regular Shaped Object

-Volume of a cube = L x W x h

-Volume of a cylinder = πr2h

-Volume of a sphere = 4πr3

3

Let’s practice! Cube: 2 cm L, 2 cm W, 2 cm h

Did you say 8 cm3?

Finding Volume of an Irregular Shaped Object

-Can’t use a ruler!!!

-Find volume by water displacement method.

-Volume of water with object – volume of water before object

-Don’t forget to read the graduated cylinder from the bottom of the meniscus!!!

What is the reading on this graduated cylinder?

56 ml

How about this one?

Be careful!!!

4.3 ml

Last one!

23 ml

What is Density?

-How much mass is contained in a given volume.

-Equation: density = mass ÷ volume

d=m/v

-What would the unit of measurement be?

You have to represent both measurements!

g/ml or g/cm3

Why is Density Important?

-Any ideas?

-Consider 1 kg of iron and 1 kg of cotton….

-Every element has its own unique density. How could that help?

The Great Archimedes

EUREKA!