Drive Systems

With another short week, we'll just get part way through investigating drive systems.  Thank you to Mrs. Rylander who brought in a whole bag of lids for us!

Drive Systems are when single wheels are used to transfer energy from one part of a device to another.  There are a few ways they can be aligned.  There is the wheel-to-wheel drive system.  Here if one is turned clockwise, the other turns counter-clockwise.  The two wheels can be moved apart, making it a belt drive system.  Depending on the alignment of the belt, the wheels can be made to turn the same direction or opposite.  For both types, if the wheel has cogs, we know it better as gears.



Mechanical advantage can be created when one wheel is larger than the other.

This is best explained by thinking about a multi-geared bicycle.  If you need advantage to go up a hill, you'd switch gears so that the chain goes on the largest cog on the rear tire.  This allows you to keep your pedals turning even if your rear tire is not rotating that fast.  If you want the advantage of building speed, you'd switch the gears so that the chain goes on the smallest cog on the rear tire.  This allows you to pedal slower but have your rear tire go faster!

Pulley Week; January 29

Pulley Week-
Knowing we were short a few days this week, we worked hard to focus our attention on this week's question:  What are pulleys? and How do they give us Mechanical Advantage?

Simple Pulley

Movable Pulley

We assembled a fixed pulley, learned how it makes work easier; we are able to lift the load by pulling toward our core (easier with our body's skeletal and muscular build).


We assembled a movable pulley, and using a fish scale, learned that although we no longer lift by pulling toward our tummy, this assembly actually decreases the necessary force by half!

Block and Tackle

Checking out the fish scale's reading on the fixed pulley

This culminated in combining the two. . . into a block and tackle assembly.  Now, we get the mechanical advantage of both- pulling towards our tummy, and needing only half the force of the load.  Check out your child's kidblog post where they were to describe their findings.



Next week - drive systems!  If you have drinking containers with the small plastic lids, would you mind collecting them and sending them in?  Thank you!

*all images from Wikipedia Pulleys