In this unit I learned about how conduction only happens when the heat source and the object are in direct contact. I also learned about how convection can only happen to liquids and gases. i also learned about heat. heat is when a warm object comes in contact with a cooler object. in this unit my favorite thing to learn was about conduction, convection, and radiation. in this unit i liked thermal energy the least. i still dont quie get radiation that when.