Ramp Cars: Wheel and Axle





Name of Activity

Ramp Cars: Wheel and Axle


Kelly Clark


ramp, cars, beams, axles, bushings, wheels, Simple Machines, Potential Energy, Kinetic Energy, friction


Simple Machines

Grade Level

K, 1, 2, 3, 4, 5, 6


1 Hour Total

Brief Description

Using LEGOs, students will build a car to travel the farthest distance off a ramp.

Lesson Objectives:

– To learn about wheels and axles.

– To introduce potential and kinetic energy.

Materials Needed:

– LEGO Simple Machine kits or homemade kits with lots of beams, axles, bushings

and wheels.

– Ramp.

– Recording sheet.

– ‘Ramp Cars’ Worksheet.

Preparation and Set Up:

– Set up a testing ramp.

— Mark starting point on ramp to start cars.

— Mark the spot at the bottom of the ramp that students will measure distance traveled from.

– Make one copy of the ‘Ramp Cars’ worksheet for each student.

– Arrange students in pairs. – Distribute materials.

Necessary Background

This activity explores the concepts of kinetic and potential energy. A car moving down a slope converts potential energy into kinetic energy. Potential energy is the amount of stored energy the car has when it is sitting at the top of the ramp. As the car moves down the ramp it converts potential energy into kinetic energy – the energy of movement of the car. At the bottom of the ramp the car has converted all the potential energy to kinetic energy. The point just at the bottom of the ramp is the point at which the car has its maximum kinetic energy. The car will slow at the bottom of the ramp due to loss of energy to the floor through friction – the force between the car tires and the ground.




Simple machine

Potential energy

Kinetic energy



  1. Tell student that they the design challenge is to build a car that will travel down a ramp and then travel the farthest horizontal distance from the bottom of the ramp.
    1. Tell students about potential energy. The energy that the car has at the top of the ramp before it is released (stored energy). This energy is converted into kinetic energy (the energy of the movement of the car has while moving).
      1. Explain that potential energy is highest at the top of the ramp (explain this by telling students that the car has the ‘potential’ to travel the farthest when it is placed here vs. when it is placed lower on the ramp). Potential energy is affected by gravity and the mass of the car.
      2. Explain that the kinetic energy is highest when the car is just at the bottom of the ramp because this is when it is moving the fastest, but has no more potential energy from being on the ramp.
      3. Explain that the force of friction – the force of the ground on the tires – is what slows the car down when it reaches the bottom of the ramp. Without friction, the car would continue to go forever in the same direction at the same speed.

  • Tell student that they can build their car however they would like using the material provided. They can change the number of wheels, type of wheels, axles, etc. Remind them to think about potential energy, kinetic energy, and the forces of friction
  • Have students build and test their cars. Allow each group three tests and record the farthest trial on the board or on a sheet.
  • Have the students fill out the ‘Ramp Car’ Worksheet.
  • Bring the class together to discuss the activity.
    1. Talk about what would be different if the ramp was shallower, steeper, rougher, or smoother. Do a demonstration if possible. Use this demo to discuss inclined planes.
    2. Discuss the different designs. Whose car went the farthest? What was different about this design? What did some of the other designs look like and why did they not go as far?
    3. Conclude by asking students how they might improve their designs.

    Extensions or Modifications:

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