Now it's an 'Engineering Principle'.

In the STEAM workshop my daughter is participating in, her assignment for the week was building a 'gear car'.  The were given a little electric motor, a rectangular form, and a box full of gears, axels and 'fiddly bits', and told...go make a car that moves. 

When I got home from work, my wifetold me my daughter might need some help.  My wife and her had spent a few hours trying to get something put together, and they were having major issues with gear alignment. Basically, they were trying to put the motor in the middle, and have gears run both directions to the front and back tires. 

All I had to do was ask one question to simply my daughters life...'Does it need to be 4-wheel drive?'

That caused the light to go off, and she got back to work.  When I came back to check on her 30-minutes later, she was done. 

Her big concern was that her design might have gone too basic.  She moved the motor down and back, and went right from one big gear off the motor, to a small gear on her drive axel.  'It's not very fancy' she felt...at which point I educated her on the K.I.S.S. engineering principle.  I said...hey...if the goal is to move the car...will this design do that?  If the answer is yes...why make it tougher than it has to be.(the gear sticking out the top is just for looks.) 

What impressed me the most is he she dealt with an issue she had keeping her gears aligned. She simply doubled up the drive gear so that it didn't mater if the axel didn't stay 100% centered.

There are only two concerns.  While they have the motors, they have didn't give the kids a way to run the motor, so she doesn't know which way the motor will rotate...so we don't know if it's front wheel drive or rear wheel drive.  And then...there isn't much ground clearance.  If they test them on a floor....that's fine.  If they have a more...interesting test, well...she's just going to have to take that chance.