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course Phy 232
6/271:00 pm
The bottle has some red stuff in it. The tube extends down into the red stuff. The cupful of dice and dominoes is just there for the weight.
Now I'm using the tube like a straw, trying to get a taste of that red stuff. Actually I'm not. The stuff is in a rubbing alcohol bottle, there's a red Mr. Sketch marker in there, and I don't want any part of it. Really I'm just trying to demonstrate a simple siphon.
You can see the red line of the tube inside the bottle. You can tell that I've managed to pull some liquid up the tube. Also some red in the tube just outside the bottle, but it doesn't quite get down to the level of the stuff in the bottle. I drew some liquid into that part of the tube, but when I eased off it went back into the bottle.
Now we have a tube full of liquid, down almost to the level inside the bottle.
I took the liquid just a little past the level in the bottle and eased off. Liquid continued filling the tube ...
... and now that it's below the level of the liquid in the bottle, it continues ...
... and continues ...
... until it gets up to the level in the bottle. Then it stops.
The liquid is still at the level in the bottle.
That's higher than the small plastic container in front of my hand.
Lowering the end to just above that container, so the end is now lower than the level in the bottle.
Slowly filling the container ...
... and it continues.
But enough of that.
Raising the tube to trap a bit of the red stuff.
Took the other end out of the bottle. I'm holding both ends of the tube up (it should be obvious why), and they're out of the picture.
I'm holding the ends too high for the camera. Should have aimed the camera higher.
Most of the red stuff has been emptied back into the original bottle.
There's a bottlecap on one end of the tube (not the end that was in the bottle). The tube goes through the cap, and it's sealed tightly. The cap fits the tea bottle, and has been screwed on. Out of camera range again, but you get the idea.
The bottle is laid on its side, and the cap is sealed.
A cap is placed on the open end of the tube, sealing it.
From the red stuff to the sealed end of the tube, there's just air. We call this the 'air column'.
The tube makes a near-circle about a 20 cm in diameter. There's a stray plastic BB inside the curve.
The red stuff comes just to the point where the tube crosses itself, just below the cupful of dominoes and dice.
I've given the bottle a bit of a squeeze. The red stuff has moved a few centimeters, so the air column between the red stuff and the end of the tube is a bit shorter than before.
The BB is gone, but that doesn't have anything to do with what we're observing. Neither does the steel washer.
Closeup of the point where the tubes cross. Squeeze is still on.
Squeeze is off.
The air column in the end of the tube obviously got shorter when the bottle was squeezed.
Can you estimate by what percent it got shorter? What was its length when the squeeze was on, as a percent of its length when the squeeze was relaxed?
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It got shorter by about 100%, from what you can see in the picture.
#$&*
Paperclips have been placed around the curve, about half on the inside and about half on the outside of the curve.
How could you use this picture to estimate the percents requested above?
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Yes, you could see how many paperclips the length was when the squeeze was on and then compare that to how many paperclip lengths it was when it was off, then
find the percentage using the length as when the squeeze was on as 100%.
#$&*
The red stuff in the tea bottle. The label has been removed.
The tube has been pulled down further through the cap, extending into the liquid. The tube is attached to the background, so that it's nearly vertical.
Squeezing the bottle, about half as hard as before. Red stuff rises in the tube.
If I squeezed harder the red stuff would rise further. Fairly short tube this time, so I won't."
&#This looks good. Let me know if you have any questions. &#