I visited the Cedar Fork Elementary School in Morrisville, North Carolina

where the students had put up a science fair. My grand-daughter Gayathri Achar in Garde I, experimented on water and ice. Here is the project:

Water and Ice

By Gayathri Achar

Question

Can water expand when frozen?

Hypothesis

I don’t think water can expand. I think ice will occupy the same space as water before it was frozen. 

Materials needed

Water, bowl

Procedure

1)      Fill a small bowl with water upto the brim.

2)      Keep the bowl inside the freezer.

3)      Wait for 6- 8 hours for the water to turn into ice.

4)      Take the bowl out from the freezer.

5)      Note the changes.

Observation

1)      Water turned into ice. A state change has occurred from liquid to solid.

2)      It has expanded or grown from the amount that we took in the beginning of the experiment.

3)      The ice can be seen above the brim of the bowl even though no water was added 

Inference

Ice took up more space than water. My hypothesis was wrong. 

Explanation

Ice is less dense than water.  This is a very special property of water.

Most substances like to scrunch closer and closer when it is colder

 but water likes to spread out like acrobats or expand when it is cold

 or when it turns to ice.

The "stuff"  in water is more tightly packed than in ice, so

water has greater density than ice. When something takes up more

space for the same amount it is said to be less dense. Ice is lighter than

 water. Even though it is the same amount of water, water will take up

 more space when it turns into ice.

Glossary

Mass = the amount of "stuff"

Density = how tightly packed the "stuff" is

                   It is the mass(amount of stuff) per unit volume(amount of space).

Volume = the area of space the "stuff" takes up