Have you ever wondered why when you sit in a chair you don't fall strait through it? This is because of Newton's third law. The chair exerts an upward force on you, and you exert a downward force on the chair. Sir Isaac Newton was born on December 25, 1642 in Woolsthrope. He was a very wise mathematician and scientist who discovered many remarkable things. He died on March 20, 1727. Over his lifetime, he discovered the three laws of motion. Newton’s third law states that every action has an equal and opposite reaction. When you have an action force on anything, there is always an equal reaction force. On this website you can learn more about Newton’s third law. Enjoy!