Support for PBS Parents provided by:

  • Cat in the Hat
  • Curious George
  • Nature Cat
  • Daniel Tiger
  • Dinosaur Train
  • Odd Squad
  • Peg + Cat
  • Bob the Builder
  • Sid the Science Kid
  • Super Why!
  • Wild Kratts
  • WordGirl
  • Thomas & Friends
  • Arthur
  • Martha Speaks
  • Sesame Street
  • The Electric Company
  • Cyberchase
  • Between the Lions
  • Mama Mirabelle
  • Caillou
  • Chuck Vanderchuck
  • Oh Noah
  • Fetch!
  • Fizzy's Lunch Lab
  • Maya & Miguel
  • Mister Rogers
  • Postcards from Buster
  • Clifford
  • SciGirls
  • Wilson & Ditch
  • WordWorld
  • DragonFly TV
  • ZOOM

Cool It!

Experiment with evaporation to keep an object cool on a hot day.

Goal: To recognize that the evaporation of water can be used to cool something.

Time: 30 minutes to an hour

Space: Desk or table


  • timer
  • 2 chocolate-covered peppermint candies in foil wrappers
  • desk lamp with adjustable height and 60 Watt bulb
  • water
  • paper towels, 5-10 sheets
  • Optional Material: 2 thermometers


  • Before starting, tear paper towel sheets into strips about 1 ½” wide. Set up a work space for your child that includes:
  • desk lamp
  • bowl of water (at room temperature)
  • 2 paper towel strips
  • 2 chocolate-covered peppermint candies in foil wrappers
  • Optional: Include paper for your child to make a paper fan and 2 thermometers.
  • Optional:  Preview the episode or clip, and if using them with your child, cue up the videos via the links above.


  1. Ask your child to share her favorite ways to cool down on a hot day (go swimming, go under a sprinkler, etc.).
  2. Invite her to dip one fingertip into some water that is at room temperature, then hold it up with the rest of the fingers on one hand. Ask: How does the wet fingertip feel compared with your other fingertips? (Cooler.) Say: Now wave the wet fingertip. How does that feel? (Even cooler.)
  3. Explain that our bodies have built-in coolers! Our sweat cools our bodies as the water in it evaporates from our skin.
  4. Optional: Use the episode or clip to further explore this idea.
  5. Ask: Do you think we can use the evaporation of water to keep a chocolate-covered patty cool so it doesn’t melt? Begin the experiment to find out.
  6. Review how your child will do the experiment. Keeping the peppermint patties in their foil wrappers, she should wrap one in a dry paper towel and the other in a wet paper towel. (To wet it, dip it into the water and wring it out.) Next, she should place the candies side-by-side under the lamp, and bend the lamp down until the bulb is 1-2 inches from the candy. Using the timer, she will time her patties for ten minutes and then check to see what happened.
  7. Optional: Have your child wrap the bulb end of a thermometer against each patty using the dry and wet paper towels. Note the temperature on each before placing under the lamp.
  8. After ten minutes, have your child remove the paper towels, open the wrappers, and compare what happened to the candies under the different conditions (wet vs. dry). If using thermometers, have her also note the temperatures on both thermometers after ten minutes.
  9. Discuss what your child observed. Ask: How did the candies compare when you opened them? (The dry one was more melted than the wet one.) If she used thermometers, ask her to describe the difference in the temperature at the end of the experiment.
  10. Ask your child if she can now think of new ways to cool down on a hot day. (For example, wrap a wet cloth around the neck or forehead!)

Take It Further

Share this activity’s Science, Technology, Engineering, Math (STEM) connections and invite your child’s comments:

In places with hot weather, engineers design misters—machines that spray a fine water mist—for use in public places to help people keep cool.

Talk About It

Ask: What did you learn today that you didn’t know before?

You May Also Like

Produced by: Funding is provided by:
WNET logo   National Science Foundation logo Northrop Grumman logo Ernst & Young logo Corporation for Public Broadcasting logo
Additional funding provided by the Volckhausen Family

What's this?

PBS Parents Picks

  1. Play Learn App

    PBS Parents Play & Learn App

    Get new seasonal backgrounds and fun fall stickers. Plus, more parent tips!

  2. Irrational Behavior image

    What to Keep in Mind About Irrational Behavior

    These incidents can be important opportunities to teach children how to manage emotions. Here's how.

  3. Science Birthday Party image

    Reading Food Labels: A Cheat Sheet

    When food shopping for young children, you only need to pay attention to a few things.

PBS Parents Newsletter

Find activities, parenting tips, games from your child's favorite PBS KIDS programs and more.