A Conversation for Ask h2g2

Physics in Action

Post 41

~ jwf ~ scribblo ergo sum

smiley - huh


Physics in Action

Post 42

Baron Grim

JWF, I believe that statement, "clearly Jack Frost is colour blind", was in reference to the original discussion about the frozen water balloons.

smiley - ok


Physics in Action

Post 43

~ jwf ~ scribblo ergo sum

smiley - bigeyes

Aha! Thank you Baron.

smiley - offtopic
~jwf~


Physics in Action

Post 44

(Mahatma) (bondage) 2legs - I survived the Great Schism of 2014 - Resident loon and Cloud Cuckoolander -- IN need of a proprietrix of a good whipping hand who owns a bullwhip. - folding towels.

The red one didn't freeze... red... Its a comunist conspiracy.... smiley - erm


Physics in Action

Post 45

Peanut

no, it is a capitalist conspiracy so that we don't hang out red balloons... smiley - erm


Physics in Action

Post 46

(Mahatma) (bondage) 2legs - I survived the Great Schism of 2014 - Resident loon and Cloud Cuckoolander -- IN need of a proprietrix of a good whipping hand who owns a bullwhip. - folding towels.

ahhh... Good point.... smiley - weirdsmiley - alienfrown I bet it all ties back to the Kenerdys, whichever way t the conspiracy goes smiley - weirdsmiley - alienfrown and that hanger in the ... err... Nivarda desert


Physics in Action

Post 47

~ jwf ~ scribblo ergo sum

smiley - scientist
>> reference to the original discussion
about the frozen water balloons. <<

Yes, and then we got off into the slinky drop thing.
smiley - bigeyes
About which, a very smart young fellow on another site
has offered me these observation:

"..and yet if you take something that is exactly the same
as a slinky except that it has no sprung tension - say a
bicycle chain - this doesn't occur which means this
"phenomenon" must be due to the sprung tension.

"So - when you hold one end of a slinky and the other end
is at rest and the slinky is stretched, the force due to
the spring must be equal to the force exerted by gravity.

"When you release the top of the spring it doesn't go
downwards at the acceleration G - it is actually slightly
faster. The top of the spring is being pulled downwards
by the same force pulling the bottom upwards.

"As the stretch of the spring decreases this extra pull
decreases too - and if you super slow-mo the effect you will
see that the slinky appears to slow down as it constricts.

"If the scientists want to show this on a youtube video they
should release a glass marble in front of the top of the slinky
at the same time. I would theorise that the top of the slinky
would initially leave the marble behind but that the marble would
appear to catch up as the spring unstretched and the two would
hit the ground at the same time. (Obviously they have to be released
in a vacuum to be really falling at the same acceleration..)"

smiley - wow
All that made me remember what happens when a rope or cable
under tension finally snaps under its load. Like on a suspension bridge or the lines on a sailing ship. There is an instantaneous
contraction of the stretched line, a whipping action, before it
then falls more slowly as that energy has dissipated and gravity
alone is in action.

smiley - scientist
~jwf~


Physics in Action

Post 48

~ jwf ~ scribblo ergo sum

smiley - doh

The main point there is:

"..the (contraction) force due to the spring must be
equal to the force exerted by gravity (for the bottom
bit to remain motionless).

In the case of bridge cables and ship's lines snapping,
and whipping dangerously about, there is initially much
more tension in the contraction than there is in gravity.
If the break is at a lower point the bottom will actually
rise upward before falling back.

smiley - cheers
~jwf~


Physics in Action

Post 49

Pastey

D'you know, when 2legs turned up I actually thought "He's a really clever guy beneath all those smilies, maybe here's the answer"

smiley - laughsmiley - run


Physics in Action

Post 50

(Mahatma) (bondage) 2legs - I survived the Great Schism of 2014 - Resident loon and Cloud Cuckoolander -- IN need of a proprietrix of a good whipping hand who owns a bullwhip. - folding towels.

Oh ye of far too much optamism faith and something... smiley - zen

My best bet would be, as an explination, is that maybe, on this night the temperature was only just dropping enough to freeze the water, in the baloons, and the one that did not freeze, just happened to be in a minutely warmer area; residual heat radiating onto that specific spot from some object near by, or more protected in some way... if it was only* just cold enough to freeze the others, then a tiny differnce in the location of the red baloon, and its heatedness or otherwise, might have been enough to mean that it didn't freeze... smiley - erm

Or, even, the time the baloon was put out, compaired to the others,
We'd need to know the temperature gradient for the evenign consirned, I.E., a graph with the temperature fall over the entire period the baloons were outside, but specifically to each of the locations in which the baloons were located... smiley - erm Or... do it again; and sit out all ngiht and watch them, and record the tempeerature, and the change in temperature/rate of cooling.... ; and discover the cat, which in th emiddle of the night peed on the red bacloon ... because everyone knows red is cats favorite colour; its why they like ripping mice open... smiley - run


Physics in Action

Post 51

Pastey

Thanks all! I shall pass the findings on smiley - smiley


Physics in Action

Post 52

Icy North

Talking of cats and balloons, there's a far better home physics experiment you can carry out.

Blow up a balloon, then rub it vigorously on the fur of a cat - it will stick to a plaster ceiling using static electricity. Young children will point at it and laugh for a while, but eventually they will ask you to bring it down so they can play with it. I often see how long it will stay up there, but usually the wife eventually asks me to retrieve it, as it might want to use its litter tray.


Physics in Action

Post 53

Tavaron da Quirm - Arts Editor

awwwww smiley - ermsmiley - laugh


Physics in Action

Post 54

Baron Grim

Then you can perform the amazing levitation experiment. Take the cat and tie or otherwise attach a buttered piece of bread to its back. Then push it off the table. Two balanced irresistible forces will come in to play; the natural tendency for a dropped piece of bread or toast to land butter side down and the cat's ability to always land on its feet.

It will hover about 1-2 feet above the floor indefinitely.


Physics in Action

Post 55

Orcus

I've never needed a cat to stick a balloon to the ceiling with static. Your own clothes or hair usually do on my experience.
I'm not sure my cats would be very pleased if I tried either smiley - winkeye


Physics in Action

Post 56

Baron Grim

You don't even need static to stick a cat to the ceiling as aptly demonstrated by Charles M. Jones in 1952: http://www.youtube.com/watch?v=ieCSUnVL-_s


Share & Enjoyâ„¢ smiley - towel


Physics in Action

Post 57

~ jwf ~ scribblo ergo sum

smiley - ok
One of the most enjoyable Chuck Jones cartoons ever!
A genuine thinking man's cartoon.
smiley - bigeyes
Lots of very imaginative physics in action - a merry
collage of shapes and situations requiring a bit of
intelligence to appreciate - like the watering can,
the water bottle, the axe! I really liked the 'obvious'
bathroom window next door and the constant self-righting
reflex in every fall. A huge improvement on the usual
RoadRunner-type anvil hits and cliff drops.
Nice one. I'd never seen that one before.
Started my day off with a genuine smile.
smiley - ta
~jwf~


Physics in Action

Post 58

Pastey

One day Icy's going to post something that isn't a joke smiley - laugh


Key: Complain about this post

Write an Entry

"The Hitchhiker's Guide to the Galaxy is a wholly remarkable book. It has been compiled and recompiled many times and under many different editorships. It contains contributions from countless numbers of travellers and researchers."

Write an entry
Read more