in this video we're looking at nuclear fusion which is when two lighter nuclei join or fuse to form a single larger nuclei for example two hydrogen nuclei like hydrogen one and hydrogen two could fuse together to form helium-3 this process releases absolutely tons of energy and is a process that fuels starts it's also how all elements heavier than hydrogen were made the reason fusion produces such large amounts of energy is that some of the mass of the original nuclei in this case those two hydrogens is being converted to energy rather than transferred to the new helium nucleus you can't tell this from looking at the mass numbers but just trust us that the helium nuclei will be very slightly lighter than the total mass of the two hydrogen nuclei you don't need to be able to calculate this energy in any way but out of interest is converted by einstein's famous e equals m c squared equation which tells us that you multiply the mass that's being lost by the speed of light squared to work out how much energy you'll be converted to and as the speed of light squared is around 9 times 10 to the power of 16 you can see why a lot of energy is released another great thing about nuclear fusion is that it doesn't produce any radioactive waste and we can easily make the hydrogen that's needed as a fuel the issue though is that fusion only happens at really high temperatures and pressures as in 10 million degrees celsius because of this we can't currently do nuclear fusion here on earth but there is a lot of experimental research going into discovering how he could do it one day the last thing i want to say is don't get nuclear fusion confused with nuclear fission nuclear fusion which we've been talking about in this video is the fusing of light nuclei to make heavier nuclei and releases tons of energy but it only happens inside stars because of the high temperatures and pressures that are required nuclear fission on the other hand is when large unstable nuclei are split into two smaller nuclei this still produces lots of energy but nowhere near as much as fusion and it's nuclear fission that we use here on earth to generate electricity anyway that's everything for this video so if you enjoyed it then do give us a like and subscribe and we'll see you soon