[Science Experiment] Can oxygen be used up to 0%?

[Science Experiment] Can oxygen be used up to 0% ?

I think I did an experiment when I was in elementary school about things such as candles that "burn". The following learning and experiments appear in textbooks in science in the sixth grade of elementary school.

 

·         Burn the candle in a closed bottle.

·         Investigate changes in gas before and after burning.

·         Oxygen is decreasing and carbon dioxide is increasing.

·         It can be seen that "oxygen" is used for combustion and "carbon dioxide" is generated.

 

With this kind of flow, do you even remember how much oxygen is decreasing and how much carbon dioxide is increasing? Actually, it looks like the table below.

 

	Before burning	After burning
oxygen	About 21%	About 17 %
carbon dioxide	About 0.04 %	About 4%
nitrogen	About 79%	About 79 %

* Nitrogen is an inert gas and does not change.

 

What I would like to pay attention to is, "Oh! There is still 17 % of oxygen left! " If "the fire goes out because there is no oxygen ", the question remains "if oxygen remains, it will still burn" .

 

In this article, I would like to consider the question, "Does oxygen stop burning below 17 %?" After reading this article, you will find that the Earth's air is in perfect balance.

 

table of contents

1.   What is combustion?

・ Fat also burns.

・  [ Experiment] [ Does it stop burning if it falls below7

・     Is oxygen or carbon dioxide the cause of the fire extinguishing?

・ Finally- It is based on an exquisite balance-

 

What is combustion?

First of all, what are "burning things" and "burning"?　

Combustion is the combination of substance and oxygen . It's easy to think of the phenomenon of "fire" as "burning," but you also say that "fat also" burns. "

By doing aerobic exercise and getting a lot of oxygen into your body, the fat in your body is burned. Therefore, aerobic exercise such as jogging and walking can be expected to have a "thinning" effect.

 

The chemical formula is as follows.

C + O 2 → CO 2 (carbon + oxygen → carbon dioxide)　　　　　

 

Some burn things but do not generate carbon dioxide

 

Burning steel wool turns it into iron oxide. Children will be delighted because the experiments that generate iron oxide are as beautiful as sparklers and have a great impact. Also, I think many people remember it.

 

Is oxygen or carbon dioxide the cause of the fire extinguishing?

Now, let's think about the first question, "Does oxygen stop burning when it falls below 17 %?"

 

[Experiment] Can candles burn in a gas of 50 % oxygen and 50 % carbon dioxide?

 

Please see the NHK video from the link below.

When you put a fire on 50% oxygen and 50% carbon dioxide ... --NHK

You can see the following.

・Candles burn even if carbon dioxide is present at 4% or more.

・Candles will burn in a space with 17 % or more oxygen .

 

In other words, candles burn "because oxygen is reduced", not "because carbon dioxide is increased".

The earth is on a perfect balance

From this, I think we can say a few things, but I feel that the Earth's ecosystem is based on an exquisite balance.

With only a little oxygen, we can't breathe and die. Also, carbon dioxide is usually very little present in the air. You can't have too many.

We are the same life on earth. I hope that you will understand that it is based on an exquisite balance and lead to living humbly.