Science Experiment – Fire and Oxygen

Time for some science!

Main Question:

What is one thing a fire need to burn? 

Answer: Oxygen

Now let’s prove it!

Beginning Questions to ask:

Do you know how a fire burns?

Did you know that fire needs oxygen to burn?

What happens to a flame when you take away access to oxygen?


Materials for Experiment:

Glass jar
3 coins
Glass bowl
Glass of Water



Place the candle in the middle of the glass dish with the coins surrounding the base of the candle and light it.


Place the jar over the candle making sure it rests on the coins and air can find it’s way into the jar to the flame.


It will stay lit as air is still finding it’s way under into the jar.

If the coins were not there to hold it up that it would extinguish as soon as there was not enough oxygen to sustain the flame.


Slowly pour water into the glass bowl. As the water covers the opening in the jar the candle with begin to go out.


It will soon extinguish and you will notice the water rise inside the jar.


Why it works:

The fire uses the oxygen inside the jar as it burns. When you take away it’s access to fresh oxygen it suffocates when there is no longer enough oxygen to support it’s flame and it goes out. The used oxygen is then replaced by water. As the air pressure is pressing down on the outside water and due to there being less air pressure inside the glass, the water is pulled inside.

Ending Questions:

What happened to the flame when the water was put into the glass bowl?

Why do you think it happened?

What do you think would happen if the jar were bigger? The candle bigger?


  1. THIS IS SO SMART! What a great/easy to execute experiment! Your little scientists are super cute too

  2. Such a fun experiment! I love how excited the kids seem to try it out! 🙂

  3. My kids would love this! My daughter is learning about the scientific process in school and keep stalking about experiments all the time!

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