This is one of the most mechanical models in You Can Tech, so you’ll like this!
True or False: You make a bicycle wheel move with your feet
Answer: FALSE! Sort of. You ACTUALLY move that gear in the middle of your pedals. It moves a chain. The chain moves your back wheel, and THEN off you go!
Why is that?
Most machines have something between the motor and the working part of the machine which makes work easier for the motor. It’s called a TRANSMISSION. That’s an engineer’s word for “send energy.”
On your bike,YOU are the motor, the back wheel is the working part, and the chain is the TRANSMISSION.
The best part of a transmission is that the machine can shift gears to make the work easier, or shift to another gear to turn faster. If your bike has a gear shift, you know that. You use some gears to make it easier to go up a hill, and other gears to go fast when it’s flat.
Let’s make a transmission with gears like one that would be in a car or truck!
On step 10, on the long black piece, there are four Lego bumps between the two blue pillars.
Ready? Turn the blue wheel with the crank on it a little so the crank is at the bottom. Now turn it all the way around 5 times. How many times does the green light on the tire spin?
Now push the axle of the blue wheel in so the black gears switch like in this picture.
Turn the blue wheel exactly 5 times around again. How many times does the tire and green light spin now?
What is going on ?!? Why is it different?
Ready for something even weirder? Change the places of the two GRAY gears so that the small gear is on the wheel and the medium gear is next to it, like this:
