When air is compressed very quickly, it can reach high temperatures. In this demonstration we show how cotton wool can reach the point of auto-ignition by quick compression of air in the fire syringe.
This is slightly inaccurate. They fail to mention that plunging also increases the partial pressure of O2 in the chamber, which lowers the temperature at which combustion occurs. In other words, the cotton is igniting at a lower temperature than it would ignite at ordinary atmospheric pressure.
This is certainly the first time that I actually understood the concept of compression heating/not heating gas in thermodynamics! Thank you Derek and Nigel!
Wow lol it's very interesting see go back and see these older, significantly less polished episodes when compared to your new, more refined episode. It really illustrates just how far you have come over the years.
@FishyArchaeologist You got it - the sliding plunger speeds up the molecules. It doesn't have to be going incredibly fast, it just needs to increase the KE of the molecules it hits.
