Background:

First graders have been learning all about the Moon and LOVE to do engineering challenges. I found this really great NASA/Design Squad challenge from https://www.jpl.nasa.gov/edu/teach/activity/roving-on-the-moon/

To introduce the challenge, I asked students what they already know about the moon’s surface. We talked about how the moon has craters and is mostly made of rock and dust with some frozen water. Then, I asked them how humans know so much about the moon. It is because astronauts travelled there! It is hard for astronauts to walk far distances on the moon because there is no gravity, so they needed to come up with a way to travel greater distances! (the moon rover!)

Challenge:

Build and test a rubber band powered moon rover! Make changes to the prototype to increase the rovers’ speed and efficiency.

Materials (per rover):

Corrugated cardboard body (6 inch square)
2 corrugated cardboard wheels (5 inch squares)
1 sharpened round pencil
2 rubber bands
2 round Wintergreen candies (with the holes in the middle) for wheels
Ruler
Tape
Scissors

Procedure:

I showed students my prototype of the moon rover and asked what they notice. Prototypes are used all the time in engineering. We can look at a prototype to understand the design’s strengths and weaknesses. Then, we can find ways to make it work better. This is all part of the engineering design process.
Build the rover! (I pre-cut the cardboard pieces for each rover and prepared the materials on trays. Students worked in pairs to build their rovers)
1. Make the rover body – Fold the cardboard into thirds. Fold along the corrugated lines.
2. Make the front wheels – On the two 5 inch cardboard squares, draw diagonal lines from corner to corner. Poke a small hole in the center (that’s where the lines cross). On the body, poke one hole close to the end of each side for the axle. Make sure the holes are directly across from each other and are big enough for the pencil to spin freely.
3. Attach the front wheels – Slide the pencil through the body’s axle holes. Again, making sure the holes are big enough for the pencil to move freely. Push a cardboard wheel into each end and secure with tape. Make sure that the pencil is taped securely onto each wheel so that when you spin the wheels, the pencil spins with them.
4. Attach rear wheels- Tape the straw under the back end of the rover. Slip a Wintergreen candy onto each end. Bend and tape the axle to stop the candies from coming off, while making sure the candies can still spin freely.
5. Attach the rubber band – Loop one end around the pencil. Cut small slits into the back end of the body. Slide the free end of the rubber bands into the slits.
6. Wind the wheels and place your rover on the ground or table. Make sure that the pencil is taped securely to each wheel and the rubber band is wound tightly around the pencil. Then, let go and watch it zoom!
After completing their rovers, students tested their models and observed it closely to point out “failure points.” Many students realized that the square wheels were creating friction and stopping the rover from sliding across the ground smoothly. They also noticed that the body was running into the wheels on the sides and decided to tape the body so the sides would stay closer together. They learned about the importance of trial and error in the engineering process. Engineers fail a lot before they make a successful product. It’s all part of the learning process!
Using trial and error, students made multiple changes to their initial designs. In the end, most teams were able to successfully launch their moon rovers!
Students drew their final designs and recorded the changes they made on this worksheet: Moon Rovers