Critique on different types of energy available to human kind?

for physics we have to write a critique on the different types of energy available to human kinda and write a description about them as well as an assesment from our point of view, i was wondering if anyone had some ideas about different types of energy

how much money can countries save if they rely on green energy ?

if a country switches from using petrol and gasoline for energy to using alternative resources can they save more money with time ? can someone give me an example of a country that did that and benefited from it ? also if you know some statistics about the matter about how much money/ energy it would save with time anything that can give me more detailed info about the matter would be very helpful

thank you 🙂

What type of experiment can I make in a 4Th grade science fair?

It can’t catch on fire or explode. I need to help a little kid. Please help me!

How long does it take for a solar cell to get a reading?

Im doing a science fair project and i need to know how long it would take for a solar cell to get a reading and start producing energy starting at the time that you put it direct sunlight.