Sign up ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free.

I bought the Lego Kit LEGO Crazy Contraptions. It allows the learner to build a blender. My son, the engineer, said something to our grandson, his son, about a gear ratio. Can someone translate?

share|cite|improve this question
gear artio is the ratio by which a set of gear increases or decreases the rotation speed – Dimensionless Mar 11 '13 at 16:00

1 Answer 1

A blender spins very fast, presumably faster than the motor supplied in that kit. A gear is a pair of cogs which mesh together to change the rotation speed. If a cog with 20 teeth meshes with one with 10 teeth, then for every 1 turn of the large cog, the small cog will turn twice. This is known as a 1:2 gear ratio, or just a ratio of '1/2'.

So to make the blender spin faster, you need a smaller gear ratio. The ratio is input:output, so you can also take a pair of cogs with a larger gear ratio and turn it around.

There's a good article on wikipedia.

share|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.