Light a fire under middle school science and heat it up! Place a burning candle in the water and watch what happens to the water. Explore how heat affects air pressure for an awesome middle school science experiment. This candle and rising water experiment is a great way to get the kiddos thinking about what is happening. We love simple science experiments; this one is super fun and easy!



This candle experiment is a great way to get your kiddos excited about science! Who doesn’t love watching a candle? Remember, adult supervision is required, though!

This science experiment asks a few questions:

  • How is the candle flame affected by placing a jar over the candle?
  • What happens to the air pressure inside the jar when the candle goes out?

Our science experiments have you, the parent or teacher, in mind.  Easy to set up, and quick to do, most activities take only 15 to 30 minutes to complete and are heaps of fun!  Plus, our supplies lists usually contain only free or cheap materials you can source from home.

Make sure to check out all our chemistry experiments and physics experiments!


Science learning starts early, and you can be a part of that by setting up science at home with everyday materials. Or you can bring easy science experiments to a group of kids in the classroom!

We find a ton of value in cheap science activities and experiments. All our science experiments use inexpensive, everyday materials you can find at home or source from your local dollar store.

We even have a whole list of kitchen science experiments, using basic supplies you will have in your kitchen.

You can set up your science experiments as an activity focusing on exploration and discovery. Make sure to ask kids questions at each step, discuss what is happening, and discuss the science behind it.

Alternatively, you can introduce the scientific method, get kids to record their observations and make conclusions. Read more about the scientific method for kids to help you get started.

Click here to get your free printable STEM activities pack!


If you want to extend this science experiment or do it as a science fair project using the scientific method, you need to change one variable.

EXTEND THE LEARNING: You could repeat the experiment with different size candles or jars and observe the changes. Learn more about the scientific method for kids here.


  • Tea light candle
  • Glass
  • Bowl of water
  • Food coloring (optional)
  • Matches


STEP 1: Put about a half inch of water into a bowl or tray. Add food coloring to your water if you like.

STEP 2: Set a tea candle in the water and light it.


STEP 3: Cover the candle with a glass, setting it in the bowl of water.

Now watch what happens! Do you notice what happens to the level of water under the jar?


Did you notice what happened to the candle and then to the level of the water? What’s happening?

The burning candle raises the temperature of the air under the jar, and it expands. The candle flame uses up all of the oxygen in the glass, and the candle goes out.

The air cools because the candle has gone out. This creates a vacuum that sucks up the water from the outside of the glass.

It then raises the candle up on the water that enters the inside of the glass.

What happens when you remove the jar or glass? Did you hear a pop or popping sound? You most likely heard this because the air pressure created a vacuum seal, and by lifting the jar, you broke the seal resulting in the pop!


Why not also try one of these easy science experiments below?

Click on the image below or on the link for more fun science experiments for kids.