Rocketing Along

 We did the second law of motion today: F=ma!  This means, Force equals motion times acceleration.  Which means if something is twice as heavy, you have to push twice as hard.  To which you respond, I knew that.

It also means that if it's not twice as heavy and you push twice as hard, it'll go twice as far (not counting pesky things like friction and such).  Which I'm sure you also knew, but doesn't it look nice dressed up as F=ma?

This is a fun one to demonstrate, but first, (IMHO) it's important for kids to learn the difference between mass and weight. I tell them that mass is how much stuff you have inside you, and weight is the downward pull (from gravity on your mass).  Then I show them the difference between a scale and a balance.

I brought out 4 scales: an old one which shows the most clearly that it's the push that moves the needle, an old postal scale, an old dial stand on scale, and a new digital scale. I think the kids could have spent the entire half hour weighing themselves and random objects.

Then I built a simple balance (as in triangular block topped by a bar of wood simple) and showed them how that worked.  Weight doesn't have much to do with it, really, you are balancing equal masses (in my case rolls of tape).  My simple balance would work on Neptune, or the moon, or even the sun (OK, maybe it would burn up on the sun, but in principle it would work!).  None of the scales are any good except on Earth!

Next we lifted weights so they could feel twice as heavy means twice the work.  It was a little difficult to get the boys to admit that twice as heavy was twice as hard...  Usually I use a medicine ball and a playground ball for this (which would have been better, I think), but I couldn't find the medicine ball. :(

Then we rolled toy cars off a ramp, adding pennies to increase their mass.  Sure enough, the more mass, the farther it went!  Here is where things started to go wrong, however.  I hadn't thought of the issue that I was using Choclo's cars.  He took great umbrage (and most of the cars) before he was done and I had to banish him to his room.

Alas, that did not put him in a good frame of mind to start cutting and taping the Puff Rockets (printable pattern and instructions here).

I had hoped that the older Zoomlians had done this recently enough to help out the younger kids.  It was not so.  If I had it to do over, I would have done it with the older kids the day before so they could really assist.  As it was, everyone was lost in the sauce and wanted HELP! RIGHT NOW!  while I needed to help the two youngest kids whose mom would be arriving real-soon-now to take them home.

At this point, Choclo and Oob began chasing each other at top speed in laps around the house (through the room we were working in) while shrieking loudly.  Yes, we do have days like this.  Not many, but some!

We did get everyone's rocket done, and everyone loved them, and went outside to play loudly with them there, so I guess all's well that ends well!

But now I need a nap.