E-Day Science Lesson #2
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Compare and Contrast
Students in a fourth grade science class conducted an experiment to
observe what happens when water changes from a liquid to a gas.
They wrote their observations in the lab report below. The report
compares and contrasts liquid water and water vapor.
Lab Report
Procedure
We put some water in a dish
and set it out in the Sun.
We left it in the Sun until all the
water was gone.
Observations
Water was liquid.
There was a white substance
left in the dish.
Interpret Results
Liquid water and water vapor are alike in some ways. Both are
made of water molecules. When water gets warmed up, it
evaporates into the air. It turns into a gas called water vapor,
which becomes part of the air. You can’t see water vapor in the
air. Water vapor is less dense than liquid water, so it floats in air.
When water is a liquid, it expands to the size of its container. It
does the same thing when it is a gas. Liquid water contains
minerals, such as salt. However, the minerals do not evaporate.
They are left behind when the water changes into a gas. Liquid
water contains minerals, such as salt. However the minerals do
not evaporate. They are left behind when the water changes into
gas.
Apply It!
Compare and contrast the liquid water and the water vapor in the
activity. Complete the graphic organizer. Write at least two ways
in which liquid water and water vapor are alike and at least two
ways they are different.
Alike
Different