Thursday, August 25, 2011

an impromptu lesson in physics

 What started out as a skip counting by two's lesson for the 5 year old with the marbles quickly turned into exploration-playtime by all three boys...

I ran upstairs to put some things away and came down to find them full of giggles, wonder and excitement.

They had discovered the glories of centripetal force as they rapidly spun their marbles around in their army helmets...  Experiencing the REALITIES of centripetal force (or anything for that matter) makes the formal learning and understanding of these concepts so much easier down the road! 

Play and discovery learning at its best.  This was just what I needed to see today...  As the birth of our little girl approaches, the plan is to take a month off.  It is always nice to see that while I won't be doing anything structured with them, learning is always taking place.

It is amazing what happens when the TV stays off and kids are given ample time and opportunity to explore and discover! 

And thankfully, I didn't have to know much about the topic with them being this age...  I love biology and chemistry, but physics makes my head spin.  I'm hoping that my engineer baby sister will be available to step in and help me out when we get into some of the more in depth physics down the road. 


  1. centripetal force and centrifugal force, action-reaction force pair associated with circular motion. According to Newton's first law of motion, a moving body travels along a straight path with constant speed (i.e., has constant velocity) unless it is acted on by an outside force. For circular motion to occur there must be a constant force acting on a body, pushing it toward the center of the circular path. This force is the centripetal (“center-seeking”) force. For a planet orbiting the sun, the force is gravitational; for an object twirled on a string, the force is mechanical; for an electron orbiting an atom, it is electrical. The magnitude F of the centripetal force is equal to the mass m of the body times its velocity squared v 2 divided by the radius r of its path: F=mv2/r. According to Newton's third law of motion, for every action there is an equal and opposite reaction. The centripetal force, the action, is balanced by a reaction force, the centrifugal (“center-fleeing”) force. The two forces are equal in magnitude and opposite in direction. The centrifugal force does not act on the body in motion; the only force acting on the body in motion is the centripetal force. The centrifugal force acts on the source of the centripetal force to displace it radially from the center of the path. Thus, in twirling a mass on a string, the centripetal force transmitted by the string pulls in on the mass to keep it in its circular path, while the centrifugal force transmitted by the string pulls outward on its point of attachment at the center of the path. The centrifugal force is often mistakenly thought to cause a body to fly out of its circular path when it is released; rather, it is the removal of the centripetal force that allows the body to travel in a straight line as required by Newton's first law. If there were in fact a force acting to force the body out of its circular path, its path when released would not be the straight tangential course that is always observed.

    Read more: centripetal force and centrifugal force —

  2. You're too cute Heather! I think you are doing a great job with those boys of yours! And the *month off* idea is wonderful...why isn't it THREE?? And when does a Mommy with (soon to be) four little people have a month *off*?? You are right...they will be learning so much in spite of the *time off*! Enjoy these precious, precious days!!

    Many blessings,

  3. hahaha. I guess a month 'off' does sound funny... And I'm in completely new territory since my oldest was only 3.5 when I had my last baby. Now I have to try and estimate how much time I will need to give myself where I don't place any expectations of getting basics like math, spelling, phonics, etc before we pick that back up again. I figured a month was at least a place to start. :)

  4. The curiosity and experimentation of children is so amazing. You are right - they are exploring and learning naturally. And I know you - you are going to be looking things up and trying to keep up with them. How do I know... because that is what I did with you and your sisters. :-)