What Makes Things Stop Moving? Grade 3 Science Lesson

📚 What Makes Things Stop Moving? - A Grade 3 Science Lesson

Objective: Students will be able to identify friction and gravity as forces that cause objects to slow down or stop moving.

Materials:

• 🧱 Toy car
• 🧽 Different surfaces (carpet, tile, sandpaper)
• 🍎 Ball
• 📈 Ramp

🌡️ Warm-up (5 minutes)

Ask students: What are some things you've noticed that eventually stop moving? Discuss examples like a rolling ball, a swinging swing, or a pushed toy car.

⚙️ Main Instruction

🤝 Introduction to Forces

• ❓ What is a force? Explain that a force is something that can cause a change in motion. Forces can make things start moving, speed up, slow down, stop, or change direction.

🚗 Friction

• 🔍 Definition: Friction is a force that opposes motion when two surfaces rub against each other.
• 🧱 Demonstration: Roll the toy car on different surfaces (carpet, tile, sandpaper). Ask students to observe how far the car travels on each surface.
• 💡 Explanation: Explain that rougher surfaces (like carpet and sandpaper) create more friction, causing the car to slow down and stop faster. Smoother surfaces (like tile) create less friction, allowing the car to roll farther.

🍎 Gravity

• 🌍 Definition: Gravity is a force that pulls objects toward each other. On Earth, gravity pulls everything down towards the ground.
• 📈 Demonstration: Drop the ball and show how it falls to the ground. Roll the ball down the ramp to show how gravity influences its movement.
• 💡 Explanation: Explain that gravity is why things fall down and why objects eventually stop rolling uphill.

📝 Combining Forces

• 🤝 Explain that often, both friction and gravity are acting on an object at the same time. For example, a ball rolling on the ground experiences both friction (from the ground) and gravity (pulling it down).

🧪 Assessment

🤔 True or False

• ✅ Friction helps things move faster. (False)
• ❌ Gravity pulls things towards the sky. (False)
• ✅ Smoother surfaces have less friction. (True)

✍️ Short Answer

• ❓ Give an example of a time you experienced friction. (Possible answer: Rubbing hands together to get warm)
• 🍎 Explain how gravity affects a ball rolling down a hill. (Possible answer: Gravity pulls the ball downwards, making it roll down the hill.)