SCIENCE FOR GRADE 1-8 Understanding Friction
When you rub your hands together they get warm. When you push your hands harder together it is more difficult to rub and you have to work harder. You work your hands to overcome FRICTION and the WORK or ENERGY you put in makes them warm.
When you slide on a smooth floor, say in the gym, you can slide farther than on a sidewalk or on sand, that is because the FRICTION is different. Slide on ice and there is almost no friction. Throw sand on the ice and there is lots of friction. Get it?
The Pole Robot has friction between the wood body and the steel pole, because the head pulls it down but at the same time the wood gets stuck by FRICTION between the wood and the steel. Only when the head start bobbing the friction goes from zero to full friction at each step. The wooden body has a hole that is larger than the wire pole and this makes it stick when it does not move!
Difficult? Yes, but look carefully (observe) how Pole Robot moves and you will get it.
Science and Technology is fun!