Sunday, March 02, 2008

physics

We've been having lots of fun with physics today!

Our first experiment was with Balanced Vertical Forces.
What happens: Daddy makes two fists, and stacks them on top of eachother (with as much force as he can), then straightens his elbows, so that his arms are extended.
Next, Trev comes along, and is easily able to separate the two fists!
Why: Vertical forces pressing against eachother cancel out each other, balancing the forces. Balanced forces will cause objects to maintain the same state of motion (in this case, rest.)The vertical forces of the hands are only pushing up and down. When pushed sideways, it can't be balanced out of horizontal force, so the hands slide easily off eachother. The harder the hands are pressed together, the easier they are to slide apart!

Next was a tower of coins.
Inertia, this time.
A tower of fifteen (or more) of the same coins.
After you make the tower as straight as possible, with a knife knock out the bottom coin. As long as the tower is stable, the resistance to change will remain! (An object in motion stays in motion, an object at rest stays at rest.)Why: The inertia of an object is directly related to mass, so the more coins there are, the greater the mass, and the easier this experiment is to do.
You have to perform this activity fast enough so that friction between the coins is not a factor - friction decreases speed.

And now, Eggs!
Mama had to try tis one by herself first, to check it out.
I was very careful to try it gently and over the sink, at first.
Cool!
"Hey, guys, come 'ere! Check this out!"
"Here, Trev, put your finger at the top of the egg, and your thumb at the bottom. Squeeze them together - what do you think will happen?"
Daddy had his turn, too, and after a few wimpy tries, finally was convinced that he could give it his best shot! (sans facial photos)Top to bottom, and then even on the sides in our palms and with our fingers!This one of course has to do with the strength of arcs.

Then we played with the World's Fastest Paper Airplane.
So cool!(We couldn't measure how fast our jets were flying, because we don't have a stopwatch.)
Mama and Daddy were curious how far it would fly outside, so....

After a short interim (Daddy wanted a quick nap) we headed outside for a bit more play.


We were interested in some more inertia action, this time in the form of rotten tomatoes (yes, we are in possession of such things) and a ball.The plan was to gauge the elasticity of a ball compared to old tomatoes. While, as already admitted we have some pretty old tomatoes, evidently they still maintained a bit of their elastic energy, because they didn't quite splat. We think it must have something to do with their temperature. We're going to leave them to warm in a window, and see what comes of it.
We are quite interested in the thermal and kinetic energy, and inelastic collisions. This one may have to wait for summertime - we'll see.

Next - a raw egg riding on top of a car - what will happen?
I was hoping for propulsion, but I thought maybe the egg wouldn't launch, as the car we were using was very light.
With the car by itself (running down the ramp) we were able to see inertia and force in action, as the car actually bounced off the wall when it hit, proving that every action has an equal and opposite reaction (energy must go somewhere).
What happened (with our egg) was that the force of the moving egg carried the car with it, causing the car to rear up, and the egg to smash against the wall.
Finally was our jetplane - we took it up to the top of the hill, though by this time we didn't have much hope - it's very windy and cold out there! (dang!)
But we still tried, though with unimpressive results.
And it (it really was) super cold, so we came back home and played in front of our house.
We had a couple of successful launches, then.This one we will definitely try again on a warm, still day. I'll bet it will fly far.

I'd say all in all, we met with lots of success.

8 comments:

  1. How cool! We tried the fists thing. Then I showed Z the egg trick and he was laughing hysterically trying to pinch and then squeeze with both hands. Then he tapped it on the counter and tried squeezing again and it EXPLODED! HAHAHA

    Thanks for posting and inspiring us to waste an egg! Always worth it!

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  2. Tara-
    Ironically, while the three of us (Trev, Eric and I) were trying to squeeze the egg into oblivion Maddie got tired of waiting for her turn, and drug the egg carton out of the fridge, and wasted like five on the floor! I'd have take a picture to capture the Funny Moment, but in that particular spot there were magnets from the fridge, and general debris, and I didn't feel like advertising a Mess!! :)
    Steph

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  3. So many inspiring experiments with kids! Looks like a lot of fun!

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  4. Okay the egg trick should not be attempted by carpenters. I'll be cleaning egg off of the walls, ceiling, floors, windows, counters, cupboards....for days. It went EVERYWHERE! LOL

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  5. Did it really?!?
    Did he cheat?!?!
    :)

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  6. No he didn't cheat LOL But he has massively strong forearms. I was really surprised. We couldn't break that thing for anything in the world. Oh and he does think mighty highly of his masculinity now. LOL

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  7. Oh - if ever you need to bring him into this realm again - have Z push apart his hands!
    heehee

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Thanks so much for sharing your thoughts!