Question: Can a fire have a shadow?

Lucien Heurtier answered on 30 Mar 2023:

Yes, absolutely! Everything which is made of atoms can block light passing through it.

Fire is basically a bunch of particles that are going so fast that they emit light on their way. So it is made of a lot of small particles. That’s why it looks so dense in light.

Think about it: if you and a friend stand on both sides of a gigantic fire and look at each other, you may not be able to see your friend. That’s because the light coming from your friend and going towards your eyes is blocked by the fire.

Now, instead of your friend, take another fire, but much brighter and bigger than the first one, and try to look at it through the small fire that we were considering earlier. Where the small fire hides the big one, you will see less light coming to your eyes, because the small fire is not that bright, and it blocks the light coming from the bigger one. If you look away from the small fire, you will see the much brighter big fire. That means… that the small fire is having a shadow on you! If you look on the floor, you will see the shadow of the small fire in the middle of the very bright light of the big fire.

However, fire is not that dense in particles, it’s a little bit like gas. So it’s not super easy to see a very sharp, clear, shadow. You would need to use a very strong source of light to really see the shadow of fire. But plus don’t do too much experiments with fire at home, this is not safe at all!!

I hope I answered your question well enough! Feel free to ask more, and don’t forget…

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