Does Fire need Oxygen to Burn? I DIY Science Experiment for Kids

F for Fire

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Fire is one thing that children might not have explored enough for the obvious reason that it’s not safe for little children to handle alone. Perhaps they know that fire is hot and it burns things. However, as they get a little older and under adult supervision, children can begin to explore the other properties of fire. Let’s do a simple experiment at home or school to check if fire needs oxygen.

Tips to introduce

(Warning: Adult supervision needed)

  • It is good to keep children away from fire. But once in a while it can be interesting for children to explore this scary element of fire under adult supervision. If this resonates with you, read the next points.
  • Begin a casual discussion on what children feel or think about fire. Allow them – give them enough space and time – to recollect their past experiences and memories about fire and how they feel about it.
  • And something not to overlook is their understanding about oxygen as well. Explaining to them that fire needs oxygen when they are not aware of what oxygen is makes no sense. So, think of ways or discussions by which you can prime them about the concept of oxygen.
  • When you think they are ready for the fire experiment, write down on a sheet the things you’ll need and direct them to collect it all at one place. Fix a time and place and let them know you’ll meet them there, then.
  • When you are at the experiment venue, explain to them what you are going to do without revealing what you are likely to observe.
  • If they are not old enough, let them watch from a safe distance while you go ahead with it.
  • Set it up and let them observe what happens!
  • Allow them to explain their inference if it is of their interest. Don’t push or annoyingly try to bring explanations out of them. Most importantly, enjoy if their rationales are not logical or correct. They are still children, and being right is not as important as being interested to observe and have fun with science. And then follow their cues to build on.

Things you’ll need

image showing things needed - bottle cut at the bottom, half cut bottle, 3 candles and matchbox

How do you do it? (Warning: Adult supervision needed)

1. Fix three candles in a line. Flame them.

2. Let candle #1 to be open. Place the half-cut bottle over candle #2 and count how many seconds it takes for the flame to go off.

3. Place the longer bottle over candle #3 and count the seconds it takes to for the flame to go off.

4. Observe what happens.


You would observe that the flame that was covered by the longer bottle took more time to go off than the one by the half-cut bottle, while the candle that was not covered continued to burn.

The Science behind

Let’s first understand the elements that keep fire flaming. This will also give children the idea about how to put off fire.

triangle showing elements that need fire to keep burning - fuel, heat and oxygen

A fuel like wood or paper, heat, and oxygen are the essential three elements that fire cannot do without. While we can easily test if fuel and heat are required for fire, we may not be able to visually identify oxygen. However, utilizing the facts that oxygen is present all around us and that a physical barrier can prevent or contain oxygen within, we can prove the third essential component – fire needs oxygen!

The candle flame that’s left open receives unlimited supply of oxygen from the free space around and it continues burning. The candle flame that’s covered with the longer bottle gets oxygen for a certain time until the oxygen that’s contained within the bottle is consumed after which the flame is cut-off. The candle flame that’s covered with an half-cut bottle contains lesser amount of oxygen than the longer bottle. And this is the reason that this one goes out sooner than the previous one.

Share your experience

Did you try? Did it work? Did you see that fire needs oxygen? Leave a word in the comment section. I would love to hear!

Here’s the full list of DIY Science Experiments in this series:

A for Air – Does Air has Weight?

B for Buoyancy – Can Egg float on Salt Water?

C for Capillary action – Rainbow Walking

D for Density – 3 Layer Density Experiment

E for Earth & Moon – Why does the Moon change its shape?: Phases of the Moon

F for Fire – Does Fire need Oxygen to Burn?

G for Gravity – Defying Gravity

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