Top: Water slides (photo by jarmoluk via Pixabay)

Children playing with soap and water (photo by Letiha via Pixabay)

Setting the Stage

Imagine your world without any friction. You sit on a chair and you slide right off. You try to stand up and your feet cannot grip the floor to push yourself up. Or, you pedal your bike and the wheels spin wildly with no effort, but the bike goes nowhere because the tires will not grab the ground to pull you forward.

Friction is the force that resists motion – it slows down motion and stops motion. Friction is caused when two objects rub again each other. Friction happens when two solid materials rub together, but it also happens when different forms of matter move past each other. (e.g., a solid moving through a fluid such as air or water creates air resistance or water resistance).

In this inquiry, students use the skills of predicting and planning a fair test to investigate how different solid surfaces affect the movement of an object on a ramp. By identifying, analyzing and interpreting patterns in the data they collect, students discover that friction, an invisible force, both helps and hinders things we do in our day to day lives.

This inquiry could begin from:

An ice-covered gravel road (photo by Huw Will via Wikimedia Commons)

  • students comparing how it feels to rub their hands together vigorously with and without a common lubricant (sliding friction). Note: Prior to doing this activity with students, check for sensitivities to smell and/or skin allergies. Discuss using questions such as:
    • “What happens when we rub our hands together?”
    • “What did you notice when we added some olive oil (or unscented hand lotion) to our hands?”
    • “What are some jobs, tasks or activities where you might want your hands to be better at gripping? What things can you do to improve the grip of your hands?” (e.g., in order to get a better grip on the apparatus, gymnasts wear special gloves and/or use chalk dust to coat their hands)
  • showing a picture of snowy, icy streets in winter. Discuss using questions such as:
    • “Why is it harder and more dangerous to walk in winter?”
    • “What can help make it easier and safer?”
    • “How does friction help or hinder us in situations like these?” (e.g., wax on skis, brakes on cars and bikes, rubber treads on shoes, grippers on pencils and pens)

    Front cover of Oscar and the Cricket by Geoff Waring (cover image by Open Library)

  • reading a book such as And Everyone Shouted, "Pull!": A First Look at Forces and Motion by Claire Llewellyn or Oscar and the Cricket: A Book About Moving and Rolling by Geoff Waring. Discuss using questions such as:
    • “What are some of the problems faced by the characters in the story?”
    • “How did the characters in the book solve their problems?”
    • “How was friction involved in causing their problems or creating solutions?”



Materials and Preparation (Click to Open)

Materials (photo by Let's Talk Science)

Materials:

  • ramp (e.g., wood, cardboard, cookie sheet, plastic cardboard, a piece of plastic eaves trough) – 1 per group
  • selection of materials with various textures and surfaces (e.g., sandpaper, aluminum foil, carpet, paper, artificial turf or grass, soil, linoleum, corduroy, flannel) – 1 set per group
  • plastic domino to travel down the ramp – 1 per group

Preparation:

Example of a marble run (photo by Let's Talk Science)

What To Do

Students use an Inquiry Journal or Inquiry Summary Learning Strategy to develop and apply the skills of Predicting, Planning: plan a process and Analyzing & Interpreting results as they learn about the properties of materials that affect the movement of an object.

Students:

Fair test set-up to compare bubble wrap, foil, paper and artificial turf (photo by Let's Talk Science)

  • compare and contrast the different surface materials available using their senses.
  • predict how each of the materials will change the motion
  • devise and record a plan for conducting a fair test of materials for their ability to slow down/stop a rolling object.
  • record observations and compare the results with their predictions.
  • analyze and interpret the results of the fair test to draw conclusions about the properties of materials and friction.

Assessment

Observe and document, using anecdotal comments, photos and/or video recordings, student’s ability to:

  • Predict - students use their prior knowledge and skills of comparing and contrasting to predict which materials and variables are most likely change the motion of an object.
  • Plan a Process to conduct a fair test - students generate a plan and carry out a controlled experiment/fair test where they keep everything constant (e.g., the tilt of the ramp, the type of car, the starting point on the ramp), have one dependent variable (e.g., the type of ramp materials) and manage data (e.g., use a chart for observations made)
  • Analyze and Interpret - students look for patterns in the results and attempt to explain the patterns they have observed.

Co-constructing Learning

Students:
Saying, Doing, Representing

Educator Interactions:
Responding, Challenging

Use their senses to compare & contrast the different materials available.

  • “What do you observe about these material?”
  • “Which senses are most helpful for comparing these materials?”
  • “How would you describe this material?”

Predict which materials will change the motion.

  • “Which characteristic(s) of the material(s) do you think will have an impact on how the domino travels down the ramp?”
  • “How do you think the material(s) will change the movement?”

Devise and record a plan for conducting a fair test of materials, working collaboratively to compare how the test materials affect the motion of the object on the ramp.

  • “What things will you plan to do to make sure the test is fair for each type of material?”
  • “Why it is important to make the test fair?”
  • “How will you record the plan for your inquiry?
  • “How will you make your plan clear so that another person could try it?”

Analyze and interpret the results of their fair test and compare results with their predictions.

  • “How would you describe your observation in words?”
  • “What observations can you measure?
  • “How will you record your observations?”
  • “How have the results of your testing compared to your predictions?“

Analyze and interpret the results of the fair test to draw conclusions about the properties of materials and friction.

  • “How did each of the different surfaces affect motion?”
  • “How would you describe the materials that slowed down the motion of the object?”
  • “How might different objects move on each of these surfaces?”
  • “What connections to ‘real life’ situations can you make based on the results?”
  • “What further tests could you do to learn more about friction?”

Feet of runner positioned at starting block (photo by tableatny via Wikimedia)

Cross-Curricular Connections

Literacy

  • use planning skills (e.g., generating ideas, gathering and organizing information)
  • make connections (e.g., between prior knowledge of materials and new context)
  • recognize and use organizational patterns in texts (e.g., put in proper sequence the steps needed to conduct a fair test)

Mathematical Thinking

Boy on a flying saucer sled (photo by MarkThomas via Pixabay)

  • measure and describe passage of time (e.g., the time in seconds it take objects to slide down the ramps) and length (e.g., measure the height in centimeters of the ramp(s) to ensure fair testing)

Physical Education

  • develop and apply effort awareness (e.g., explore the impact of friction on body movements in various sports activities such as running on different surfaces, playing games on different surfaces; identify examples of friction in action during games and activities)
  • develop awareness of the benefits of technological innovations with regard to personal safety, injury prevention and performance:
  • A clap skate increases friction because the blade stays on the ice for longer during the stroke (photo by Max Dohle via Wikimedia)

    • e.g., compare materials and technical innovations in sports equipment or sports clothing to reduce or increase friction such as racket grips, running cleats, ski wax, no-wax skis, roller skate brakes, shoe grippers and slippers for curling, curling brooms, clap skates for speed skating, Fastskin™ swimsuit material, full-body swimsuits, body suits for speed skating and luges

Music

  • create compositions for a specific purpose and audience (e.g., create a friction soundscape using different techniques and surfaces in the classroom such as rubbing hands across different textured surface or rubbing surfaces of two objects together to make sounds)

Extending the Learning

  • How does the length of the ramp change the motion of the object? Conduct a fair test using ramps of different lengths and the same variety of different surfaces (e.g., wood, carpet, grass cement, dirt) to see how the length of the ramp affects the movement of the object.
  • How does the weight of an object affect its motion? Conduct a fair test using objects of different weights (e.g., big marble, small marble, bigger toy car, etc.) with the same set-up and variety of surfaces to explore how the weight of an object affects its movement.
  • How does the height of the ramp affect motion of an object? Conduct a fair test using ramps of different heights/angles using a similar set-up and variety of surfaces.

Large excavator being unloaded from a ship (U.S. Navy photo by Paul Farley via Wikimedia Commons)

Long waterslide (photo by paulbr75 via Pixabay)