Grade 3 Science Worksheet on Forces & Gravity: Friction and Surfaces with Diagrams and Activities

Instructions

Read each question carefully and answer to the best of your ability. Think about how things move and stop in the world around you!

Part 1: What Do You Know? (Objective Questions)

Draw a line to match the surface on the left with the amount of friction it creates on the right.

Circle the best answer for each question.

6. What is friction?
   • A. A force that speeds things up
   • B. A force that stops or slows things down
   • C. A type of magnet
7. Which surface would be best for sliding down a slide quickly?
   • A. Sandpaper
   • B. Smooth plastic
   • C. A fuzzy blanket
8. Why do we put special grooves (called treads) on car tires?
   • A. To make them look cool
   • B. To increase friction with the road
   • C. To make the car quieter
9. When you rub your hands together quickly, friction creates...
   • A. Light
   • B. Cold
   • C. Heat
10. A toy car rolling on a thick rug will eventually stop because of...
    • A. Gravity
    • B. Friction
    • C. The color of the rug

Read each sentence. Write 'T' if it is true and 'F' if it is false.

11. ____ A smooth surface has more friction than a rough surface.
12. ____ Friction helps a pencil make a mark on paper.
13. ____ Without friction, you would not be able to walk or run.
14. ____ Friction can only happen between two solid objects.
15. ____ Putting oil on a bicycle chain increases friction to make it stop.

Complete each sentence using a word from the word box below.

16. Friction is a force that ________________ down moving objects.
17. A bumpy, ________________ surface creates a lot of friction.
18. A ________________ surface like polished wood has very little friction.
19. The friction on the bottom of our shoes helps us ________________ the ground.
20. If you rub two sticks together very fast, friction can create enough ________________ to start a fire.

Part 2: Think About It! (Subjective Questions)

Write your answers in the spaces provided.

1. What would happen if there was suddenly no friction in the world for one minute? Describe two things you might see.
   
   
   
2. Why is it harder to push a heavy box across a carpet than across a tile floor?
   
   
   
3. Give one example of when friction is helpful. Explain why.
   
   
   
4. Give one example of when friction is unhelpful or annoying. Explain why.
   
   
   
5. Look at the two surfaces below. If you roll a marble on each one, which surface will make the marble stop first? Why?
   Surface A (Smooth): _________________________________
   Surface B (Rough): /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
   
   
   
6. Imagine a soccer player kicking a ball. How does friction help them?
   
   
   
7. Why do we put oil on a squeaky door hinge?
   
   
   
8. If you are riding a scooter, how do you use friction to stop?
   
   
   
9. Think about writing with a pencil. Where is the friction happening?
   
   
   
10. Why do astronauts' gloves have special grippy material on the palms and fingers?
    
    
    

Answer Key

Part 1: What Do You Know? (Objective Questions)

Activity A: Matching Surfaces to Friction

1. 1. A wet, icy sidewalk → B. Low Friction
2. 2. A sandy beach → A. High Friction
3. 3. A fuzzy carpet → A. High Friction
4. 4. A smooth, polished floor → B. Low Friction
5. 5. A grassy soccer field → C. Medium Friction

Activity B: Multiple Choice

6. B. A force that stops or slows things down
7. B. Smooth plastic
8. B. To increase friction with the road
9. C. Heat
10. B. Friction

Activity C: True or False?

11. F
12. T
13. T
14. F (Air resistance is friction between air and an object)
15. F (Oil reduces friction to make it move smoothly)

Activity D: Fill in the Blanks

16. slows
17. rough
18. smooth
19. grip
20. heat

Part 2: Think About It! (Subjective Questions - Example Answers)

1. What would happen if there was suddenly no friction...?
   Example: Cars would not be able to stop. People would slip and fall over and couldn't get up. Everything would slide around.
2. Why is it harder to push a heavy box across a carpet...?
   Example: The carpet is a rougher surface, so it creates more friction, which pushes back against the box. A tile floor is smooth and has less friction.
3. Give one example of when friction is helpful.
   Example: Brakes on a bike use friction to stop the wheels. Friction helps us walk without slipping.
4. Give one example of when friction is unhelpful.
   Example: Friction can wear out the parts in a machine. It can make it hard to slide something heavy. A squeaky door is caused by friction.
5. Which surface will make the marble stop first? Why?
   Example: Surface B will stop the marble first because it is rough and creates more friction.
6. Imagine a soccer player kicking a ball. How does friction help them?
   Example: Friction between their shoes and the ground stops them from slipping when they kick.
7. Why do we put oil on a squeaky door hinge?
   Example: To reduce the friction between the metal parts so they move smoothly and quietly.
8. If you are riding a scooter, how do you use friction to stop?
   Example: By putting my foot down on the ground or by pressing the brake, which rubs against the wheel. Both use friction.
9. Think about writing with a pencil. Where is the friction happening?
   Example: The friction is between the tip of the pencil lead and the surface of the paper.
10. Why do astronauts' gloves have special grippy material...?
    Example: To increase friction so they can get a good grip on tools and equipment while in space.