Journey to the Earth’s Core





Name of Activity Journey to the Earth’s Core
Author Kristen Burns and Sarah Halpert
Keywords sturdy car, rock, travel, ramp, layers, earth, crust, mantle, core, axles, bushings, car, density, plate tectonics, mass, friction
Subject Simple Machines
Grade Level 4, 5, 6
Time 1 Hour Total
Brief Description The kid’s needed to design a sturdy car that will hold a rock (small pebble). The car will then
travel down a ramp that is labeled with the layers of the earth. The upper half of the ramp
was the crust and the lower half of the ramp was the mantle. The floor directly after the ramp
was labeled the outer core and following the outer core was the inner core section. The kids
had to adjust the axles and bushings on the car to allow it to travel farther. Once the cars were
finished we tested them on the ramp to see how far into the “earth” they went.
Lesson Objectives: Review density and how to measure the mass of an object

Build a sturdy car and tweak it to allow it to travel the furthest down the ramp

Learn the layers of the earth

Materials Needed: Simple Machine Kit

Materials for a ramp

Paper to cover the ramp that depicts the layers of the earth

Small rocks


Preparation and Set Up: Get a large piece of paper and cut it down to fit the ramp while allowing some extra to account
for the outer and inner core section. Design the paper with fun facts about each layer
(temperature, thickness, etc.).
Necessary Background Vocabulary:

Plate Tectonics


Axle and Bushing


Procedure 1. Explain density and the theory of plate tectonics. Also, review how to measure the mass of an object. 2. Have them start building the cars. Make sure that the cars have a spot to hold the rock and that they are sturdy. Explain how to adjust the bushings to account for less friction. 3. Take the mass of the rock. 4. Test the cars on the ramp and see how far into the “earth” they were able to travel. 5. Fill out the worksheet.
Extensions: If a group finishes early ask them if they can make the car go further.

Tow Truck





Name of Activity Tow Truck
Author STOMP
Keywords steep, ramp, tow, towing, weight, gears, gear up, gear down, building, design, friction, gravity, center of gravity
Subject NXTs
Grade Level 4, 5, 6, 7, 8, 9+
Time 1 Hour Total
Brief Description Build a car that can climb a steep ramp while towing a weight (10 batteries) behind it.
Using gears to gear down is necessary for this challenge. This activity is more challenging
than a regular ramp climb and may require some complex building and design.
Lesson Objectives: - To learn to build and use gears.
- To learn about gravity, center of gravity, and friction.
Materials Needed: NXT kits
batteries for weight
computers running NXT Software
Preparation and Set Up: Build a ramp.

Set up computers running NXT software.

Arrange student in groups of two.
Distribute necessary materials.

Necessary Background It is more difficult for cars to climb steep slopes for different reasons. In this lesson you
can discuss with the class these different forces that affect the ability of the car to
climb the slope:

Friction – friction is the force acting between the surfaces of the car (tires) and
the ramp surface. This is the force that keeps the car from slipping.
Gravity – gravity pulls down directly towards the center of the earth. On a flat
surface gravity does not pull a car in any direction, but just keeps it in place. On
a slope, gravity pulls a car backwards towards the center of the earth down the ramp.
Center of gravity – Center of gravity is the exact spot on an object where there
is the same amount of weight on one side of the spot as there is on the opposite
side. A high center of gravity means a car is more unstable on a steep slope.
A low center of gravity close to a ramp will help the car stay on the ramp.To
overcome these forces there are several things that you can do to your car:
Low center of gravity – design the car to be low to the ground.
Gear down the car – By adding gears to the motors and then gearing to the
wheel you can increase the power of the motors, which will help the car climb
the ramp. There is more information about gears and gear worksheets in the
attached documents.

Gear Ratios
Center of Gravity

  1. Have students design and build a car that will climb a ramp.
    1. Students will need to think about friction and center of gravity to build their car. If students are unfamiliar with these concepts, you should review the concepts with them. A car that is lower to the ground will be less likely to slip. Wheels that have more traction and greater surface area on the ramp will also be less likely to slip.
    2. Students will need to use gears to gain more power. If students are unfamiliar with using gears, you should review gears and gearing down with the students.
  2. Have students program their cars to move forward for 20 seconds.
  3. Allow students to test their cars on the ramp without anything in tow.
  4. Students should redesign the car if it does not climb the ramp.
  5. Students should then test their cars while towing the weight up the ramp and redesign until the car can tow the weight.
  6. If students have trouble tell them to try various gears, wheels and designs.
Extensions: What is the steepest ramp that the car can climb?
What is the heaviest weight that the car can tow?
Calculate the gear ratio.
What is the quickest that the car can travel up the ramp?
Reference 1
Reference 2
Reference 3
Reference 4
Reference 5
Reference 6
Reference 7

Bicycle Unit: Engineering the Wheel






Name of Activity Bicycle Unit: Engineering the Wheel
Author STOMP
Keywords bikes, force, friction, rolling, ramp, travel, wheel, tire, LEGO
Subject LEGO Building
Grade Level 4, 5, 6
Time 1 Hour Total
Brief Description Using bikes as an example, students will examine the force of friction. They will apply their knowledge to build an object that rolls down a ramp and travels as far as possible.
Lesson Objectives: - To experiment with wheel sizes, shapes, and materials.
- To learn about the affect of friction on bike tire design.
- To practice teamwork and competition.
Materials Needed: - Ramp (made of wood, cardboard, foamcore etc.) that is approximately 25 cm high at the top.
- Tape lines to mark where to start measuring distance.
- Ruler.
- ‘Ramp Roller Challenge’ and ‘Tire Chart’ Worksheets.
- Homemade LEGO kits (consisting of different types of wheels, axles, bushings, beams, bricks and weighted bricks).
- Other materials that cars could be constructed out of:
– Wood, cardboard, straws, old containers, art supplies, blocks, etc.
Preparation and Set Up: - Create kits to make cars with.
- Make a ramp that is about 25 cm high and mark starting point on ramp and start point for measuring distance at the bottom of the ramp.
- Photocopy a ‘Tire Chart’ worksheet for each student.
- Photocopy a ‘Ramp Roller Challenge’ Worksheet for each student.

- Arrange students in pairs.
- Distribute materials.
Necessary Background Wheels must respond to a lot of forces. Riders weight, Bumps and dips, Weight of the frame, Wheel itself.
Friction is a force that affects the wheels of a bike because tires are the part of the bike in contact with the road. Friction is the force that appears when two things rub together (rub your hands – makes heat). The smoother two objects sliding against each other are, the less friction there is. Microscopic ridges are what interact with each other when any two objects meet. If a wheel had no friction it would not be able to move a bike; it would just spin in one place. However, too much friction causes a rolling wheel to slow down, and makes it harder to pedal.


Procedure Part 1:

  1. Show students two different bike tires; one from a mountain bike and the other from a road bike (pictures are fine, the real thing is better).
  2. Have each student fill out the ‘Tire Chart’ worksheet attached to this document to examine the properties of each wheel and the reason that property is there.
    1. E.g., MOUNTAIN BIKE WHEEL - Property: wide tires, Reason for Property: More surface area on the ground for better stability
  3. Discuss, as a class, the different forces on tires and the design features that account for these forces.

Part 2:

  1. Have students build an object that will travel the farthest once it rolls down a ramp.
  2. Remind the students that you used the word “object” because they do not have to design anything that resembles a car.
  3. Once students have built their original design, let the students test their design on the ramp.
    1. Students should record their results on the ‘Ramp Roller’ worksheet: the distance traveled from the bottom of the ramp, and the design changes that they make.
  4. Have students redesign or make changes to their original design and retest.
  5. Students get a total of three trials.
  6. When everyone has finished bring the class together for  class discussion.
    1. Talk about different factors that affected the distance the cars traveled.
    2. Talk about how weight might have affected their cars.
      1. Tell students that, for some of their designs, adding weight did not help because it added friction to the place that the axle went through the beam. The more mass on the car the more friction there would be between the wheel’s axle and the hole that supported the rest of the car.
    3. Compare different designs.
      1. Which design was the best?
      2. How could other designs be improved?
    4. Review how friction affected designs, and point out all the different places that friction had an effect on a vehicles performance for each model.
Reference 1
Reference 2
Reference 3

Ramp Cars: Wheel and Axle





Name of Activity Ramp Cars: Wheel and Axle
Author Kelly Clark
Keywords ramp, cars, beams, axles, bushings, wheels, Simple Machines, Potential Energy, Kinetic Energy, friction
Subject Simple Machines
Grade Level K, 1, 2, 3, 4, 5, 6
Time 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.
    2. 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
  2. Have students build and test their cars. Allow each group three tests and record the farthest trial on the board or on a sheet.
  3. Have the students fill out the ‘Ramp Car’ Worksheet.
  4. 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: You can modify this activity to be applicable to older grades by having student graph distance v. time, taking the mass of their cars and predicting how far their car will travel using mathematics.
Reference 1
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Reference 3

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