Science Buddies: "Ask an Expert"

What does the power switch exactly do? Why do the resistors have different numbers and what do they stand for? Thank you so much!

I need to make my robot slower, but I don't have a 3 battery pack, so could I "short" it out by using a jumper wire, like the trouble shoot process demonstrates? If not, is there anyway I can do this with a 4 battery pack. Thank you.

Sorry for all of the questions, but why can my robot follow the track from one direction, but not the other? It's the exact same thing but just in a different order. Do you know why? Thank you so so sooo much!

Hi Saida22551,
The power switch turns on and off the electricity going to the circuit. (Or more specifically, it's actually a piece of metal that connects the "power source" to the "load." Using the water pipe analogies, it's the valve that you turn on when you want water.)

I am not sure about the number on the resistor that you are referring to. If, for example, you are talking about 220 ohm, that's the resistance value of the resistor. (The important thing about this number is that it tells you how much electrical current will travel through the circuit using this resistor. In the water pipe world, this would be the size of the pipe or the position of the valve where you are controlling how much water flow.)

In regards to reducing the voltage / making your robot slower. Yup, you can use the same method as the troubleshooting describes. You may have to make additional modification though to make sure that you have the + side of the battery 1 connected to the - side of the battery 2, (+ of battery 2 to - of battery 3, etc...)

In regards to the your question about direction, try reversing the polarity (i.e. flip the + and -) and it should travel in the other direction.

Good Luck!
Willey