Guided notes to introduce students to gears and then experimenting with combinations of different sized gears. You will need different sized gears, measuring tape or rulers (or tape measuring out 2 feet), and timers.
I suggest completing this activity in partners and with a decent amount of space (not on tables!) as the robot will move much faster than students expect. Make sure one student is ready to "catch" the robot to prevent it from running into walls.
After completing this activity, we take the next couple of days to do "drag racing" (to see who can make their robot move the fastest). Depending on which model they have built they may need to create "wheelie bars", as they call them, to prevent the robot from tipping back. Again, make sure there is someone to catch the robot. We also do "turtle races" to see who can get their robot to travel a certain distance the slowest (I would make this a short distance and some can take a long time!).