Mechanical System Definition
Date: June 2008
Our state requires us to have second grade students
describe a mechanical system. What would be a definition that a
second grade student could understand?
I am not familiar with Montana's requirements, so I recommend you contact
your science education coordinator to make sure this is on point for your
specific requirements. However, I'll take a stab at what I think they mean,
and I hope it will be useful for you.
A mechanical system is any set of elements that have physical/force
interactions (as distinguished from chemical, electrical, thermal, etc.). In
terms of a second grader, I would focus on forces, or "pushes and pulls".
You could define a mechanical system as a set of objects that push or pull
on each other. At its simplest level, one object resting on another could be
considered a mechanical system. Perhaps a little more interesting, pulleys,
springs, inclined planes (with rolling balls), and pendulums all could be
fun mechanical systems to study. The key learning objective would be to list
and understand the mechanical interactions. I might start with asking the
kids to list if/how each object pushes or pulls each other object (do not
forget to point out the objects that *do not* interact!). You can distinguish
between forces due to gravity and non-gravity forces. Point out that objects
will not move until a force acts on them, and they will stay moving until a
force stops them (inertia).
I am happy to go more into detail if you have more questions -- just reply to
Hope this helps,
Why MT requires this -- blows my mind -- its value at the K-3 level is
dubious at best. More likely useless. OK!! off my soap box -- Do a "Google"
search on the term "simple machines". You will find many "hits" describing
'simple' machines such as pulleys, levers, inclined planes, etc. You should
be able to extract concepts from these numerous sites to put a lesson plan
If not, respond and I will try to dig deeper into your specific details.
A bicycle, an air conditioning unit, a car. You know, it was a lot easier to
explain when can openers were manual and clocks and watches were mechanical.
Best wishes on your class.
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Update: June 2012