Density of Water Lesson

DENSITY OF WATER LESSON

​
In the previous lesson, you learned how to find the volume of an object by using the water displacement method. You also saw that if objects all have the same mass, the one with the smallest volume must be the most dense, and the one with the largest volume must be the least dense.

You also saw that the size, mass, and arrangement of atoms and molecules in a substance determines the density of the substance.

​In this lesson, you’ll focus on the density of water. So far, you’ve only examined the density of solid objects, but liquids also have density because they have a certain mass for a certain volume. You’ll examine water all the way down at the molecular level to understand more about its density.

Let’s take a look.

Fill in the Blanks

Open Ended

What did you notice about the density of water with any sample of volume?

​The density of water doesn't change even if you use different amounts of water. 100 mL of water has a mass of 100 grams. 50 mL of water has a mass of 50 grams. 25 mL of water has a mass of 25 grams. The ratio of mass to volume stays constant and is 1 g/cm³.

​Take a close look at this graph which shows how the mass of water is related to its volume. These points are (25, 25), (50, 50), and (100, 100).

Fill in the Blanks

Fill in the Blanks

Multiple Choice

Look at the models of two samples of water showing the water molecules, and answer the questions. Sample B is half the volume of Sample A.  Each individual molecule has the same size and mass. Water molecules are packed closely together in the same way throughout both samples of water.

Sample B is half the volume of Sample A. Which statement is true?

• Sample B has the same mass as Sample A

• Sample B has twice the mass as Sample A

• Sample B has half the mass of Sample A

• Sample B has some other mass

​Comparing densities with water - why do some objects float in water?

Density is a measure of how heavy something is compared to its size. If an object is more dense than water it will sink when placed in water, and if it is less dense than water it will float. 

Density is a characteristic property of a substance and doesn't depend on the amount of substance.

Poll

if an object has a density of 0.9 g/mL, will it float in water?

• Yes

• No

Poll

if an object has a density of 27 g/mL, will it float in water?

• Yes

• No

Denser objects or liquids will sink or be "below" liquids that are less dense. 

Try this question about densities of various liquids..

Fill in the Blanks

Fill in the Blanks

Fill in the Blanks

Multiple Choice

Put the liquids in order from most dense to least dense.

• 4,3,2,1

• 1,2,3,4

• 3,4,2,1

• 4,3,1,2

Copy these notes....

𝐊𝐞𝐲 𝐂𝐨𝐧𝐜𝐞𝐩𝐭𝐬 - 𝐃𝐞𝐧𝐬𝐢𝐭𝐲 𝐨𝐟 𝐖𝐚𝐭𝐞𝐫

The density of liquid water is 1 g/cm³, regardless of the size of the sample.

The density of a substance is the same regardless of the size of the sample.

 

Poll

Did you copy the notes?

• yes

• no

Complete Density Assignment.

Google Classroom

Classwork

Assignments

9/18  Density Assignment

Begin Exploring Density Simulation Lab