In the Grade 3 project, Building Boats, students are learning about density. The density of an object is a measure of how tightly matter is packed together. 

Try It At Home

1. Fill two clear plastic cups with water.     

2. Place an egg in the first cup. See if the egg sinks or floats. Draw what happens in the "freshwater" cup below.  

3. Mix 3 tablespoons of salt into the second cup and put the egg in. Now, draw what happens to the egg in the "saltwater" cup below. 

How It Works - Let Us Take a Closer Look!

　An egg is more dense than freshwater so it sinks in the freshwater. When you add salt to water, the salt dissolves into the water and makes the water more dense. The egg is now less dense than the saltwater, so it floats!