What caused a cpu to give off heat?

Sounds like you need to do your own research for school. Google will help you with a simple search.

menopause?

You may want to look into the transistor and why it heats up. Since cpus have millions+ of them, you will have your answer.

In short, Nothing is 100% efficient and cpus despite getting better(still turn most of the power into heat) still transform a good portion of the power coming in to them into heat.

thanks nuke, i asked because the only thing i would find is why laptops are getting really hot, and thats it

Laptops due to a small space for heat sinks and fans will get hotter(Unless its a R3000 from HP, that had great cooling   ), but the chips are generally the best of the best(Lower power and lower heat) and designed to take the heat(from the lower powered cooling system) without damage.