Question

Science 7 Grade 7. Can anyone please help me answer these science questions?

Answer 1

A cellphone battery is a electrical energy 
and a piston in an engine is an thermal energy

Answer 2

Thermal expansion in a balloon occurs because when the balloon is heated up, the gas molecules will move faster and in greater distance so when if they move faster then they will hit the wall with greater force, will result to expansion.

conduction, convection and radiation are the ways that thermal energy is transferred.

a cellphone battery is an electrical energy, then piston in an engine is mechanical energy