Density Lesson

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By Derek Wuthrich

Mass is defined as the amount of matter an object has. It is not affected by gravity, and doesn't change based on location.

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Mass differs from weight because weight is affected by gravity.​ Weight is the force of gravity pulling down on you.

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Mass is measured in kilograms.​

​Fun fact! You will weigh less on the moon than you do on Earth! But you will weigh more on Jupiter!

​Mass

All matter takes up space. The amount of space an object takes up is called its volume.

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Volume can be measured in cubic meters (m³), cubic centimeters (cm3), liters, and milliliters (mL​).

​What is volume?

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Rectangular objects - calculate volume by using the formula:​

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Volume = Length x Width x Height.​

​Volume is measured in different ways depending on what shape the object has.

Let's practice using this formula on the next slide.

One way would be to put the object in liquid that is inside a graduated cylinder. The liquid in the cylinder will rise the same amount as the volume of the object.

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Subtract the final liquid volume reading from the starting volume reading to find the volume of the object.​

Science tool definition: A graduated cylinder is a tall narrow cylinder with markings used to measure volume of liquids!

​So, then, how do you measure the volume of an irregular shaped object?

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To calculate the density, use the following formula:

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Density = mass / volume​

(mass divided by volume)​

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​Scientists use density to measure matter because each material has a specific density.

Let's practice calculating density!

• ​Particles are closer together

• Less space between

• Typically sink- density is higher than the liquid it is in​

High Density

• Particles are more spread out

• More space between

• Typically float- density is lower than the liquid it is in​

Low Density

Multiple Choice

Which of the following is the least dense?

• honey

• water

• vegetable oil

• corn syrup

Multiple Choice

Which of the following is the most dense?

• milk

• lamp oil

• corn syrup

• water

Multiple Choice

If an object has a mass of 15 g and a volume of 5 mL, will the object float or sink if the density of the liquid it is added into has a density of 1.5 g/mL?

• Float

• Sink

• Not enough information

• Tool to help you remember your formulas

• ​M= D x V

• D= M/V

• V= M/D ​

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Density- Mass- Volume Triangle

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Multiple Choice

An object has a mass of 20 g and a volume of 10 mL. What is the density of the object?

• 200 g/mL

• 20 g/mL

• 2 g/mL

• 0.2 g/mL

Multiple Choice

If the object has a mass of 4 g and a volume of 8 mL, will the object do if added to water?

• Float

• Sink

• Not enough information

Multiple Choice

What is density?

• the amount of space taken up by an object

• the amount of mass in a certain space

• the amount of matter in an object

Multiple Choice

What is required to find density?

• mass

• volume

• both

• you can find it without either of the other two

• Take an initial reading on the cylinder

• Take the mass of an irregular object and add it to the cylinder

• Read the new level on the cylinder.

• The difference is the volume ​of the irregular object

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How to use Water Displacement

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Multiple Choice

What is the volume of the irregular object?

• 2 mL

• 4 mL

• 65 mL

• 69 mL

Multiple Choice

What is the volume of the regular object?

• 10 cm³

• 15 cm³

• 20 cm³

• 40 cm³

Multiple Choice

True or False: The density of a specific type of material never changes.

• True

• False

Multiple Choice

What is the density of a substance that has a mass of 55.4 g and a volume of 10 cm3?

• 0.554 g/cm³

• 5 kg/l

• 5.54 g/cm³

• 554 g/cm³

Multiple Choice

Density measurements and weight measurements are, essentially, the same thing.

• True

• False

Multiple Choice

Which liquid is the least dense?

• 1

• 2

• 3

• 4

Multiple Choice

In this image, a British pound coin is floating on liquid mercury. What can we determine?

• Mercury is more dense than the coin.

• Mercury is less dense than the coin.

• Mercury has the same density as the coin.

• Not Enough Information.

Multiple Choice

Which of these boxes is more dense?

• Box A

• Box B

• They are the same

• Not enough information