Focus Question: Where does
the water go when something dries?
Investigation 3 - 1
Wet and Dry
When it rains and the pavement
gets wet, who dries it?
We’re going to do an investigation
to find out where the water goes.
Place both paper towels in the
Squeeze out most of the water and
place one towel in each cup.
Place cups on balance and add
drops of water to lighter cup until
Paper towels get wet when people use them
to soak up spills. They can sometimes be used
again if they are dried out. These two towels
are equally wet.
Watch these for a day to see how fast they
To make things a little more interesting, cover
one cup with a lid. Place the second lid
under the other cup so it still balances.
Sketch the investigation set-up in the Before
box on your observation sheet.
Sketch the investigation in the After box.
Take the paper towels out of the cups,
compare them and describe the difference.
Discuss in your group:
Which side of the balance went up and which
side went down?
What caused one cup to go up and one to go
What happened to the water on the two paper
The paper towel exposed to air dried out.
The water in the towel changed from liquid water
to water vapor, an invisible gas.
Process by which liquid water changes to water
vapor is called evaporation.
Water vapor in the open cup evaporated
and escaped into the surrounding air.
Water in the closed cup was not able to
escape into the air.
All the original water stayed in the closed
When the water in the open cup
evaporated, the paper towel got dry.
Water in the closed cup didn’t evaporate, so
the paper towel stayed wet.
Wet paper towel is heavier, so that side of the
balance goes down and the side with the dry
paper towel goes up.
Record your explanations on the notebook
sheet. Include what happened to the
balance, the paper towels, and the water.
Evaporation - The process by which a liquid,
such as water, changes to a gas
Water Vapor - The gas state of water
What happens to a wet paper towel in an
What happens to the water in a paper towel
when it evaporates?
Homework: Read “Drying Up”, pages 182-183,
take 3-column notes and answer questions.
Drying Up Questions
What is water vapor?
Where is water vapor?
What does water vapor look like?
What happens when a wet object gets dry?