Easy Solar Heat Beam Activity (No Spaceship Required!)

Learn about solar energy with this fun activity.

By Liz Heinecke
Sep 09, 2016



Easy Solar Heat Beam Activity (No Spaceship Required!)

Sep 09, 2016

Get your child excited about solar energy! On a sunny day, it's simple to use the energy of the Sun, Earth's very own star, to pop balloons and cook marshmallows.

Safety tip: Never look directly at the Sun. Sunglasses are recommended, since the focused spot of sunlight will be very bright.

You'll Need

  • A sunny day
  • Magnifying glass
  • Balloons
  • Marshmallows

How to Do the Activity

Get ready to experiment! For younger kids, it may work best to show them how to hold the magnifying glass before having them give it a try.

Step 1: Blow up a balloon. This experiment will work best with a balloon filled with plenty of air.

Step 2: Stand with the Sun behind you.

Step 3: Hold the balloon in front of you with one hand, and position the magnifying glass to focus the Sun's light into a very small, bright spot on the balloon. Ask your child what they think will happen.

Step 4: Keep the Sun's energy focused on a single spot on the balloon until it pops. Be patient!

Step 5:  See what happens to a marshmallow if you do the same thing. Set a marshmallow on a plate or foil on the ground. Find a way to prop up your magnifying glass to keep the sun's energy focused on the marshmallow.

Step 6: Check on the marshmallow every few minutes to see what the Sun's energy does to it.

The Science Behind the Fun

Light waves from the Sun carry lots of energy that can be transferred to matter, like a balloon or a marshmallow. When these waves pass through a magnifying glass, the curved lens can bend them to focus on a single spot.

If you focus the Sun's energy on a balloon filled with air, it heats up the rubber, weakening it enough to pop the balloon. When the energy is focused on a marshmallow, it toasts it and may even burn it. The amount of heat you can focus on an object depends on the size of the lens in your magnifying glass.

You can find more experiments like this one at kitchenpantryscientist.com, and in my books Kitchen Science Lab for Kids (Quarry Books) and Outdoor Science Lab for Kids (Quarry Books).

© Quarry Books, 2016/Outdoor Science Lab for Kids
Featured Photos Credit: © Quarry Books

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