Why does magnesium burn in water - Science

Magnesium. It is a metal that is used in many things that range from cars to vaccines. It is well known for being very brightly visible when burning. But another thing it can do is burn underwater. I am here to investigate how.

Experiment

Aim: To find out how Magnesium burns in water

Equipment: Magnesium Strips, Bunsen Burner, Beaker

Method:

1. Light the Bunsen Burner
2. Light Magnesium in the bunsen burner
3. Once alight, drop magnesium in the water

Observations: When magnesium was on fire, it set off its signature white glow. Once dropped in the water, the magnesium lasted about 0.5 seconds before being put out. I tried many times but the same thing happened every time

Conclusion: Magnesium does burn in water sometimes, but not this time for me

I have seen some videos on this and they all worked in different ways. One was a guy spraying water on to it, another was some guy doing it similarly to mine using a beaker, however, he only held it at a high level in the water, about surface level. This allowed oxygen to get to it better and allow it to keep burning. In my experiment I just dropped it in, disallowing this to happen and ultimately it went out.

So obviously magnesium only burns in the water when held at a certain level and allowed oxygen.

I thought this until I saw another video
In the video, the person drops the magnesium in the water in a similar way to me, but it continued to burn in the water. This has perplexed me to as why mine did not work. The way magnesium can burn in water is when magnesium burns so hot that it is able to separate water molecules. Water is made up of Hydrogen and Oxygen. Hydrogen is flammable and Oxygen is basically fire, so you get the picture. 

Thanks to this random person I found on the internet

This begs the question. If magnesium burns so hot that it can literally break up water, does the temperature of the water depend on if it will work? The answer is no as the average temperature of cold tap water (the type I used) is around 7 degrees Celcius. Magnesium burns at about 2200 degrees Celcius. There is a temperature difference of 2193 degrees Celcius. That's hotter than the surface temperature of Venus, the hottest planet in the solar system.  There is a possibility that the chlorine in the water could've affected the way the experiment went. Chlorine is not flammable but I doubt that there is not enough chlorine in the water supply to stop it from happening. But for now that seems like the most likely cause, and when we stop getting chlorine in the water I'll have to try it again and see. But until then, I'll have to do other experiments.

Videos:
1.First Video
2.Second Video
3.Third Video

I had fun with this experiment and hope to get to do more in the future

Please give me feedback and let me know what to do better