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.

Relay Race





Name of Activity Relay Race
Author STOMP
Keywords vehicles, steep ramp, relay, team, course, cars, gears, weight, weight distribution, friction, power, accuracy, wheel, axle, speed
Subject NXTs
Grade Level 4, 5, 6, 7, 8, 9+
Time 2 Hours Total
Brief Description Students will build two types of vehicles, one that is good for going fast on a flat surface and one that is good for climbing a steep ramp. Students will work together to create a relay team of 2 cars that must complete a course with a flat area and a steep ramp.
Lesson Objectives: To learn about gearing and how it can help with climbing ramps.
To learn complex programming that includes Bluetooth for communication between NXTs.
Materials Needed: Poster board, cardboard, wood or foam core for a ramp sloped about approx. 30 degrees from the horizontal.
NXTs or RCXs
Assorted building materials.
Computer running ROBOLAB or MINDSTORMS
Preparation and Set Up: Setup the relay course.
Set up a flat track that is five feet long with a start and finish and set up the ramp.
Collect necessary materials.
Arrange students into groups of 4.
Distribute the necessary materials.
Necessary Background One of the important things about robots is their ability to communicate to each other. Robots are often limited in their capabilities because it is too difficult to construct multi-tasking robots. For this reason, many different specialized robots are constructed, and then these robots are programmed to communicate to each other. For example, a certain Mars rover may specialize in searching for rock, while another may specialize in drilling rock. These two rovers can work together by sending signals to each other, in the same way we communicate, yet simpler. The following activity incorporates specialized robots that can communicate to each other to complete different sections of a single task: a relay race with different terrain.


Mechanical advantage of gears
- Small gear on motor, larger gear on wheel and axle for more torque to drive up the ramp
- Large gear on motor, small gear on wheel and axle for more speed to drive across the floor

Weight distribution of vehicle
- More weight on the front of the ramp vehicle
- Less weight for the entire floor vehicle

- Wide wheels for more contact surface area on the ramp vehicle
- Narrow wheels for less contact surface area on the floor vehicle
- Spacing between wheels and sides of vehicle so that the wheels rotate without rubbing

- Large diameter wheels in the front of the ramp vehicle
- Ramp vehicle should be short in length

- Long floor vehicles with four wheels to ensure that the vehicle travels as straight as possible towards the stationary ramp vehicle

  1. Introduce the activity and tell students that two people in their group will build and program a car to travel as fast as possible on a flat surface, and the other two people will be building a programming a car to drive up a ramp.
  2. Allow students to build their cars. Remind students that gears might help them build a car that can climb a ramp.
  3. Have students program their vehicles.
    1. The first vehicle must travel 5 feet to the base of a ramp and then stop. The students should use time to stop their robot, or use a light sensor if the course is marked with tape.
    2. When the first vehicle stops, it must send a message to the second vehicle (a number). This will trigger the second vehicle to start climbing the ramp.
    3. The second vehicle should start climbing the ramp when it receives the message from the first vehicle.
    4. Communication between RCXs/NXTs may be tricky.
      1. Use the ‘send mail’ and ‘wait for mail’ icons on the floor and ramp vehicle, respectively.
      2. Each group should send a different number so as to avoid confusion between RCXs and NXTs.
      3. Zero the receiving mailbox at the beginning of the program.
      4. Press run on both robots before starting the relay.
  4. Allow students to test their cars and rebuild/reprogram accordingly.
  5. At the end of class gather the students together. Have each team run their cars and time how long the relay takes from start to finish.
  6. Talk about what designs and programs worked the best and how you could improve upon each teams work.
Reference 1

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

Bicycle Unit: Materials Testing





Name of Activity Bicycle Unit: Materials Testing
Author STOMP
Keywords material choices, strengths, weaknesses, materials, static load, dynamic load, friction, physical properties, chemical properties, mechanical properties, elasticity, yield strength, ultimate strength
Subject Non-LEGO
Grade Level K, 1, 2, 3, 4, 5, 6
Time 1 Hour Total
Brief Description Students will learn about different materials that bikes are made out of. Students will learn about different factors, material strength, flexibility, cost, weight etc. that affect an engineers decision when choosing a material to use in constructing a prototype/real thing.

To apply this information, students will test and rate the strength of different types of materials. They will record the strengths on a chart and compare the different materials. Students will discuss the factors that affect an engineer’s choice of materials.

Lesson Objectives: - To explore the factors that affect material choices for a design.
- To compare strengths and weaknesses of different materials.
Materials Needed: - Hot glue sticks.
- Popsicle sticks.
- Plastic spoons.
- Wire.
- Metal Rods (e.g. thin nail).
- Activity Worksheet.
Preparation and Set Up: - Print out enough worksheets for the class (either one per group or per student)
- Optional: Set up large version of real bike materials sheet.pdf or make copies for each group to look at.
- Arrange students into groups.
- Distribute materials and worksheets.
Necessary Background Engineers need to keep a lot of things in mind when choosing what material they will use in their designs.

A bike will have two types of loads. The Static Load – the bike frame must support itself – and the Dynamic Load – the bike frame must support changing forces of a cyclist’s weight, forces of pedaling and breaking, road’s surface (bumps, holes)

Friction – or the resistance of the road’s surface. This factor affects the engineers decision on what a tire should be made out of and how it should be designed. Road bikes want to reduce friction for faster movement v. mountain bikes, which want wide tires for increase friction to reduce falls.

Materials that engineers choose for their designs must withstand all of these forces. There are three categories of material properities that enable bikes to function to suit different purposes

Physical: Density, color, electrical conductivity

Chemical: Reactivity, rust resistance, solubility, reaction to heat.

Mechanical: hardness, stiffness, expansion, toughness

Different tests of mechanical strength are:

Elasticity: When a material can be bent and come back to its original shape.
Yield Strength: The point at which a material is bent and it keeps the new shape.
Ultimate Strength: The point at which a material is bent and it breaks.

Static load
Dynamic load
Physical properties
Mechanical properties
Yield Strength
Ultimate Strength
Chemical properties

  1. Explain the concepts mentioned in the Teacher Background section. Tell students about the things that engineers must keep in mind when choosing a material.
    1. Go over Static and Dynamic Loads, and discuss the differences.
    2. Go over friction on tires – when you might want more friction (mountain bikes) and when you might not (racing road bikes).
    3. Talk about physicalmechanical and chemical properties (e.g., physical – weight of the bike for easy of carrying; mechanical – the amount of weight the bike must hold without breaking; chemical – rust resistance for a long-lasting frame).
    4. Talk about elasticityyield strength, and ultimate strength and how these strengths are different and necessary (e.g., a bike frame should have a high ultimate strength but should not be easily bent, even if it does return to it’s original shape).
  2. Discuss why engineers choose certain materias and why they avoid others. Remind students that there are reasons other then strength. Talk about costs, looks, availability, appearance, durability, aerodynamics etc.
  3. As a class, go over the attached chart labeled “Real bike materials sheet”.
    1. Evaluate the differences between steel, aluminum, carbon and titanium.
    2. What are the pros and cons of each material?
    3. Ask students what material they would choose to build themselves a bike.
  4. Distribute materals to the class and give instructions on the activity.
    1. Tell them that they are researching the pros and cons of five different materials.
    2. Pass out the ‘Activity Worksheet’ and materials to be tested. Explain the test categories.
      1. Looks – rate from 1 – 10 the way this material would look on a bike frame.
      2. Weight – rate from 1 – 10 how heavy the material is.
      3. Cost – Rate from 1 – 10 the cost of the material (help students who do not know relative pricings).
      4. Elasticity – rate from 1 – 10 how much the material returns to its original shape when bent.
      5. Yield Strength – rate from 1 – 10 how easy is it to bend the material out of shape.
      6. Ultimate strength – rate 1 -10 how easy it is to break the material.
    3. Have students fill out the chart for the five materials.
  5. When the student have finished testing, have them return to their seats to discuss the activity. Ask:
    1. Which was the best material?
    2. Were any of the materials strong in all of the categories?
    3. What are the trade-offs to using one material over other materials?
    4. Which materials were the strongest (high yield strength and ultimate strength)?
    5. If you had to build a bike out of these materials what material would you choose?
    6. What are other factors we could have considered?
Extensions or Modifications: - Give students limitation, such as cost or weight, and have them choose the best material.
- Talk about what material would be best for a different item (cars, computers, kitchen appliances, etc.).
- Add different material to the list to test.
Reference 1
Reference 2

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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