Compare the forces of pushing and pulling. Demonstrate that gravity is a force. Demonstrate that a force is required to overcome gravity. Use measurement to demonstrate that heavier objects require more force than lighter ones to overcome gravity. Compare the incline of a hill to the motion of an object rolling up or down the hill.
Heat is produced by the sun and observed on Earth.
Living organisms use heat and light from the sun. Heat is also produced from motion when one thing rubs against another. The motion of rubbing objects together may also produce heat. Provide evidence that shows that the sun is the source of heat and light for Earth. Observe and report how sunlight affects plant growth.