Make a Cardboard Rover

Take a close look at the prototype of a rover above. Prototypes are used all the time in engineering. They give you a basic design from which to build, test, and evaluate. Improving a design based on testing is part of the engineering design process.

Ask yourself these questions:

• What do you have to do to make the rover move?
• How do you think square wheels affect how the rover moves across the floor?
• How can you make improvements to the wheels?

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Fold the cardboard into thirds along – not across – the corrugation (the open veins inside the piece of cardboard), pushing up the sides of the rover body to form a trench. Each section will be about 2 inches (5 cm) across.

On the two 5-inch (13-cm) cardboard squares, draw diagonal lines from each of the corners, forming an “X”. Poke a small hole in the center with a pencil, where the lines cross.

Important! Avoid accidentally poking yourself with the pencil. Keep your hands away from where the pencil will go through the cardboard.

Use a pencil to carefully poke a hole near the top of each of the two outermost sections on the rover body. Again, keep your hands away from where the pencil will go through the cardboard. Make sure the holes are directly across from each other and are big enough for the pencil to spin freely. This is where your axle will go.

Slide the pencil through the axle holes. Carefully slide the cardboard wheels onto each end of the pencil and secure them with tape.

Tape the straw across the bottom of the rover body on the opposite side from the pencil. Slip a candy onto each end of the straw. Bend and tape the ends of the axle to stop the candies from coming off.

Create a chain with the two rubber bands as shown in the image above.

Loop one end of the rubber band chain around the pencil, as shown in the image. Cut small slits into the front end of the rover body. Slide the free end of the rubber band chain into the slits.

Turn the back wheels to wind the rubber band around the axle and power up your rover.

With the rover on the floor, let go! Observe what the rover does. Measure the distance it traveled.

For an added challenge, you can use microdevices to ensure that your rover wheels allow for a smooth ride as they cross the terrain.

1. Using a device such as a microbit, you can code simple parameters based on whether your rover is shaken too quickly as it goes over rough surfaces. First try using the on shake function in the input menu. Inside, place a show leds block and draw a diagram to be displayed if the event is triggered, such as an X or a frowning face.
2. Next to this, place the on button input and set it to A+B. Place a clear screen block inside. This will allow the experiment to be cleared and repeated across all trials.
3. With the code downloaded to your device, add a battery pack. Secure the device and battery pack to your rover to ensure they stay connected.
4. As you refine your rover, consider how the wheel shape and rubber-band power affect how level and steady of a drive you observe.

Rovers are a kind of car-like spacecraft that NASA uses to explore the surfaces of other worlds, such as the Moon and Mars. In 1971, astronauts with the Apollo program became the first to drive around on the Moon using a lunar rover. Today, we use robotic rovers to explore Mars. Since we can't yet send astronauts to the Red Planet, Mars rovers are controlled remotely by operators back on Earth, but they might one day be used by astronauts to drive around on the surface.

Watch this talk to find out more about Mars rovers and get a sneak peak at how to create your own. Scroll below for written step-by-step instructions with photos.

About the image: On the left is the Lunar Roving Vehicle, or LRV, that Apollo 15 astronauts used to drive around on the Moon. On the right is the Perseverance Mars rover pictured with the Mars helicopter, Ingenuity. | + Expand image