This workshop is a novel method of investigating rates of reaction.
The car has a light dependent resistor (LDR) linked to the motor. A beaker of the reaction mixture sits on top of the car with a mixture in that is a variant of the iodine clock reaction. The car is set going and when the reaction mixture goes black, the car stops. Measurement of the distance travelled can be used as a surrogate for time.
In the absence of the car, the reaction can simply be timed.
Nb The circuitry is quite complicated (though we are looking at a simpler version). If you have the cars from someone attending a previous workshop then the materials are all here. If not, it is probably best to talk to someone with electronic skills to make the circuit up.