Because they're safety devices, circuit breakers have to work automatically. (Of course, you can also operate them manually, which you should always do when doing DIY electrical work.) Here are ...

How do you get ... so I'll send electricity round the rope,and when it passes through your motor, what happens?I spin! Whee! So, Greg, that circuit that we made, would that work in real life?

If the resistance of any component in a parallel circuit changes, this will change the value of the current in that loop and the total current supplied by the battery. It does not affect the ...