Isaac Newton came up with some important ideas called the Laws of Motion. These laws help us understand how things move and how forces work on them. While there are three laws, today we’re going to focus on the third one. This law tells us that for every action, there is an equal and opposite reaction. It’s a big part of how things interact around us every day.
Newton’s third law is pretty simple: if one object pushes or pulls on another object, the second object pushes or pulls back with the same strength but in the opposite direction. This idea helps us understand how things like bicycles, cars, and even our own bodies move.
Let’s think about what happens when you drop a tennis ball on the floor. When the ball hits the floor, it pushes down on the floor. This is called the “action.” The floor then pushes back up on the ball with the same amount of force. This is the “reaction.” These two forces together are called an action-reaction pair.
You can see this in action when you bounce a ball. The ground pushes back on the ball just as hard as the ball pushes on the ground, which makes the ball bounce back up.
Now, let’s see how this law works when you’re riding a bicycle. When you pedal, the bike’s tires push backward against the ground. According to Newton’s third law, the ground pushes the tires forward with the same force. This is what makes the bicycle move forward.
You might wonder what happens to the Earth when the bike tires push against it. The Earth is so big and heavy that the force from the bike doesn’t make it move. But the force from the Earth is strong enough to push the bike forward, letting you ride smoothly.
Learning about Newton’s third law of motion helps us understand many things we do every day, like playing sports or riding bikes. By noticing these action-reaction pairs, we can see how Newton’s ideas explain the way things move. Whether it’s a ball bouncing or a bike rolling, these interactions show us how amazing and useful Newton’s laws are in our world.
Bouncing Ball Observation: Find a small ball, like a tennis ball or rubber ball, and drop it from different heights. Watch how it bounces back. Try to notice how the height from which you drop the ball affects how high it bounces back. Discuss with a friend or family member why the ball bounces back and how this relates to Newton’s third law. Can you think of other examples where you see action-reaction pairs in your home or playground?
Bicycle Push Experiment: If you have a bicycle, try gently pushing it forward while it’s on a flat surface. Notice how the wheels turn and the bike moves. Now, try pushing it backward. Talk about how the ground is pushing back on the wheels in both cases. Draw a picture of what you think is happening with the forces when you push the bike forward and backward. How does this help you understand how a bicycle moves?
Action-Reaction Role Play: With a partner, take turns being the “action” and the “reaction.” For example, one person can gently push the other on a swing, and the person on the swing can describe how they feel the push back. Switch roles and try different actions, like pushing a toy car or bouncing a ball. Discuss how each action has a reaction and how this helps things move. Can you think of a fun story or game that involves action-reaction pairs?
