rAs Kids🛢️ ➕ 🔋 ➕ ⚙️ ➡️
🎒 What you need
- a small DC motor from a broken toy car, fan or CD player
- a battery holder or two AA cells, plus wire or foil strips
- a cut-open jerry can or strong plastic bottle, caps for wheels, tape, and an adult nearby for cutting
✋ Do this
- SAFETY FIRST: only small batteries — AA or AAA. Never mains electricity, never a car battery, never a charging cable cut open. Ask an adult to do the cutting.
- Touch the motor's two wires to the two ends of the battery. It spins. Now swap the wires over. It spins backwards — point at that. You just learned how a robot reverses.
- Cut the jerry can into a low open boat shape. That is your chassis. Fit your bottle-cap axles from module 2 underneath.
- Tape the motor at the back so its shaft touches one wheel, or push a cap onto the shaft to make a drive wheel. This takes fiddling. Fiddling is the job.
- Twist a wire loose so the rover stops, twist it back so it goes. That loose wire is your switch.
- Let it run across the yard. It will veer. Measure how far it goes before it leaves a straight line — write the number on the can.
💡 Why it works
You now have all three robot parts in one object: a body (the can), an actuator (the motor), and a control (your wire switch). Swapping the wires reverses the motor because you reversed the direction of the current — real robots do that with a little circuit instead of your fingers, but the trick is identical. It veers because no two wheels ever grip quite the same, which is why real rovers constantly correct themselves.
🔥 Challenge
Make it go straighter without buying anything. Try heavier at the front, wider wheels, or a small trailing stick at the back. Measure before and after.
📖 New words
motorthe part that turns electricity into spinning
chassisthe body frame everything else is attached to
circuitthe complete loop electricity travels around
🛻
Rover Rigger
Tap when you have finished this module.