Friction Lab Investigation Sheet

Experiment Title: The Push and Pull of Surfaces

Objective

To investigate how the type of surface affects the force of friction.

Materials

• Small object (e.g., wooden block, eraser)
• Spring scale or rubber band
• Various surfaces (e.g., sandpaper, felt, wood, smooth plastic, carpet)
• Ruler or measuring tape (optional, for consistent pulling distance)

Procedure

1. Choose one small object to test.
2. Attach the spring scale (or rubber band) to your object.
3. Place the object on your first testing surface (e.g., wood).
4. Slowly pull the object across the surface at a constant speed, noting the force reading on your spring scale just as the object begins to move, and then as it continues to move. If using a rubber band, note how far it stretches.
5. Record your observation in the data table below.
6. Repeat steps 3-5 for each different surface.
7. Make sure to pull your object in the same way each time!

Data Collection

Observations

Describe what you noticed during your experiment. Which surfaces felt rougher or smoother? What happened when you pulled the object?

Analysis Questions

1. Based on your experiment, which surface created the most friction? How do you know?
   
   
   
   
   
   
   
2. Which surface created the least friction? How do you know?
   
   
   
   
   
   
   
3. How does the texture of a surface affect the amount of friction it produces?
   
   
   
   
   
   
   
4. Imagine you are trying to slide a heavy box across the floor. What could you do to reduce the friction and make it easier to move? What could you do to increase the friction to make sure it doesn't slide?
   
   
   
   
   
   
   
   
   
   
   
   
5. Think about rubbing your hands together really fast. What do you feel? How is this related to friction?
   
   
   
   
   
   
   

Friction in a Bag Sorting Game

Objective

To identify and categorize real-world examples of helpful and hurtful friction.

Materials (per group)

• One large bag or container
• Pre-prepared cards or small objects representing scenarios/items (see examples below)
• Two labels: "Helpful Friction" and "Hurtful Friction"

Instructions

1. Divide into groups: Work with your assigned small group.
2. Set up your sorting area: Place the "Helpful Friction" and "Hurtful Friction" labels in two separate areas on your desk or table.
3. Explore the bag: Carefully take out each card or object from your bag.
4. Discuss and sort: As a group, discuss whether the example represents friction that is generally helpful to us or hurtful (undesirable).
   • Helpful Friction: Friction that makes things work better, allows us to do things, or keeps us safe.
   • Hurtful Friction: Friction that creates problems, wastes energy, or causes wear and tear.
5. Place the item: Once your group agrees, place the card or object under the correct label.
6. Be ready to explain: Be prepared to share some of your sorted items with the class and explain why you categorized them as helpful or hurtful.

Example Cards/Objects (Teacher will provide these!)

• Helpful Friction Examples:

  • Tires gripping the road
  • Brakes stopping a bike
  • Shoes allowing you to walk without slipping
  • A match striking to light
  • Sand on an icy sidewalk
  • A rock climber's hands on a rock face

• Hurtful Friction Examples:

  • Engine parts wearing out
  • A rusty door hinge squeaking
  • Pushing a heavy box across carpet
  • Wind resistance slowing down a race car
  • Holes in your socks
  • Heat generated by rubbing hands together too much (can be both, but here focus on inefficiency/wear)