A Conversation for Ask h2g2

Physics in Action

Post 21

Icy North

We get this situation all the time on IT support desks. There are many perfectly logical explanations - you just need to do a bit of troubleshooting to find the right one.

Can you ask the user if they'd be happy for you to take remote control of the balloon, so they can repeat the operation while you monitor it?

Did they actually upload the right screenshot, or did they just use the one they happened to have handy at the time?

Failing that, I'd raise a case with the red balloon vendor, assuming you've got premium support.


Physics in Action

Post 22

Pastey

Given my friend is a professional photographer Icy, I'd imagine it's the correct photo smiley - biggrin


Physics in Action

Post 23

Orcus

Seeing as noone as asked.

What's with freezing water filled balloons anyhow?

Are we planning a (quite literal) game of winter It's A Knockout?


Physics in Action

Post 24

Baron Grim

http://twitter.com/ladycrafthole/status/278803560492318720/photo/1

That should fix the image link. (The 's' in https breaks links in ripley skins.)


I'm with Whisky in suspecting that the frost came first. It could be that there is something microscopically different about the surface of the red balloon that make is more apt to frost over, maybe a chemical in the coloring produces tiny nodes for the ice crystals to form on. With a layer of frost on it, the balloon is better insulated from conductive and convective cooling.


Physics in Action

Post 25

Orcus

>maybe a chemical in the coloring produces tiny nodes for the ice crystals to form on<

More likely it just got some dirt on it.


Physics in Action

Post 26

Magwitch - Community Editor, Moderator, Sub Editor and Scout - Are you reading The Post every week?

I am repeating the experiment.

I will be taking photos.


Physics in Action

Post 27

highamexpat


I think its something to do with radiation and where they were placed. My knowledge of Heat transfer between 2 bodies is a little rusty now but I seem to recall the amount of heat transfer from hot to cold involves the Fourth power of T1-T2 and the Stefan Boltzman constant which is very small. (x 10 -23) if they are well out in the open then they are looking at outer space which the temperature is around -273K

It is the reason why some car windscreens freeze up if they are parked in the open looking to the sky. sorry I can't be more specific but I did all this some 30 years ago and have never used it since.


Physics in Action

Post 28

Mu Beta

Thoughts:

smiley - popcorn Whisky's explanation about the chemical make-up of the rubber was my first thought. Polymers are coloured with 'filler' molecules which will crystallise the structure to a greater or lesser extent. This would make the walls thicker and a better insulator.

smiley - popcorn The 'frost as cause' theory doesn't add up if all the balloons were kept in the same place. Why would one get frost if the others didn't?

smiley - popcorn However, the 'frost as effect' has a lot of currency for me. The red balloon is likely to reflect less radiation as a darker colour. Therefore the exothermic change inside the balloon is smaller (because the heat has nowhere to go - the fact that the red is noticeably less transparent is another important factor here). The heat released as the other balloons froze was sufficient to melt the frost.

B


Physics in Action

Post 29

~ jwf ~ scribblo ergo sum

smiley - laugh

Some of us are still wondering what one wants
with balloons filled with frozen water. Is this
some sort of practical joke where one is invited
to kick the balloons or worse yet to dive into a
pile of them expecting them to have the flexibility
of air filled balloons?

smiley - huh
~jwf~


Physics in Action

Post 30

Pastey

It was in the first sentence of the opening post jwf, "so that she could use them for outdoor decorations."


Physics in Action

Post 31

~ jwf ~ scribblo ergo sum

smiley - ok
>> "so that she could use them for outdoor decorations." <<

Yes, I saw that and I understand they would be less
likely to blow away if frozen, but that word 'decorations'
suggested to me there was to be a party of some
sort involved and I pictured guests and party games
including Kick the Balloon, etc. I shared Orcus's
unanswered curiosity from post 23, perhaps missing his
irony and taking serious concern for possible injury.

It had momentarily escaped me that it is THAT time of
year when folks put up all sorts of desacrations of the
outdoor variety just for the sake of it and the general
pleasure of passers-by, who, (g'bless 'em) deserve what
they get if they try putting the boot into these ornaments.

smiley - cheers
~jwf~


Physics in Action

Post 32

Magwitch - Community Editor, Moderator, Sub Editor and Scout - Are you reading The Post every week?

The experiment has failed, it wasn't cold enough for them to freeze. smiley - sadface


Physics in Action

Post 33

Alfster

A wide shot of the area the balloons were in and how they were arranged would be useful as I think it would be. For some reason the red balloon was not losing as much heat as the others - I don;t thing black body type stuff is relevant for losing heat so colour shouldn;t have anything to do with it.

There is some ice on the balloon which means some cooling was happening but I doubt it would be acting as an insulator otherwise the other balloons once they had some ice forming in them would not go solid.

Was the red balloon out of wind, next to a wall, on a bit of ground warmer than the others.

Essentially, there was less heat transfer from the red balloon than the others.

The point about car windscreens in the same street not all freezing due to different orientation of the cars is a good point.


Physics in Action

Post 34

Bald Bloke

Nothing to add to the freezing balloons, it's not cold enough here and I don't have any balloons for two things

However el reg has an interesting article / video of Slinky physics in Action.

http://www.theregister.co.uk/2012/12/14/falling_slinky_defies_gravity/


Physics in Action

Post 35

~ jwf ~ scribblo ergo sum

smiley - huh

That slinky video has me baffled.

I mean, can you really trust anything posted
at the Register? Is this a total hoax?

The interview seems almost genuine but some
of the less than scientific jargon from the main
guy leaves me convinced it's all just a bit of
CGI fakery.

smiley - erm
~jwf~


Physics in Action

Post 36

Mu Beta

I'm sure it's genuine, although the explanation doesn't convince me.

Springs are basically wires placed under tension and that tension force is stronger than gravity (in fact, pretty much every force is stronger than gravity).

I suspect the design of the slinky in question is of more importance than they're letting on: a very tightly-wound spring wouldn't 'hang down' under gravitational force: if you repeated the experiment by stretching one of those, you would see the bottom coils move up before the whole thing started falling.

B


Physics in Action

Post 37

~ jwf ~ scribblo ergo sum

smiley - ok
>>..you would see the bottom coils move up
before the whole thing started falling. <<

Yes, that is my vague memory of the way it works
when you dangle one and then let it go. I seem
to recall thinking it was the last vestiges of
friction from the fingers pulling away from the
top that was transmitted thru the coil causing
the bottom to rise even as the top began to fall.
But there was always some residual bouncing and
flexing of the coil already in motion - wind and
an unsteady hand and all that.

The given explanation of a 'signal' being sent
down the wire strikes me as quite fanciful and
somewhat un-scientific but it does coincide with
my 'insight' that the friction of letting it go
gives a last shot of impetus to the 'spring'.

Egad, I'm as vague and in-articulate as the guy
in the video. We need a real scientist here. And
a fresh slinky for further experiments.

smiley - cheers
~jwf~


Physics in Action

Post 38

Bald Bloke

I have a Slinky but no slow motion camera...

attempting to re-create this by hanging the slinky from a door frame with cotton and the cutting the tread using a stanley knife on the end of a pole.

Visually it does appear to work!!!
I can say that the bottom does not appear to move until after the top has been already falling for a split second.

so it looks like the videos are right.

what a way to spend a Sunday afternoon after going to the pub for lunch. smiley - cheers

Going through the explanation again I think he's got it about right, he says that with a more rigid spring the effect would still be there but too short to see.


Physics in Action

Post 39

Baron Grim

Yep... this is completely valid. I've seen this demonstrated in a physics class (twenty blah blah years ago). As noted in the video above, the center of mass falls at the expected rate of 9.8m/s^2.


Physics in Action

Post 40

Beatrice: It's NaNoJoMo time!

Surely we're missing the obvious answer here - Jack Frost is clearly colour blind.


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