Psychic Humour ?

[facthunter]

It's only a heater if it's adding heat. Only the insulation will slow it going down to the lower ambient.  Nev

 

 

[onetrack]

Fridges give off heat in any ambient temperature, regardless. The same goes for RC air conditioners. Put them on cool and the condenser on the outside of the house gives off heat. That's the basic principle for all cooling/refrigeration setups.

 

Many a home was burnt down by kero fridges with blocked flues, they were tigers for it. Even lost a building myself to one (on our minesite - fortunately it was an old, 3 roomed Fettlers timber cottage, that we'd trucked in, so not a huge loss).

 

 

[bexrbetter]

Psychic thoughts .......................... :

 

If it weren't for electricity we'd all be watching television in the dark

 

 

 

 

 

[440032]

Does a fly do a half loop or a half roll to land on the ceiling?

 

 

[planedriver]

An eskimo married a nice Jamaican girl, and when their kids went to school, they were called choc-ices

 

 

[nomadpete]

Quote/"Does a fly do a half loop or a half roll to land on the ceiling? "

 

When I was a young impressionable bloke, that very question caused a group of us to spend an entire long weekend  consuming excessive amounts of alcoholic voice lubricants, in order to solve this important aviation conundrum. We never did come up with the answer.

 

 

[Marty_d]

Quote/"Does a fly do a half loop or a half roll to land on the ceiling? "

 

When I was a young impressionable bloke, that very question caused a group of us to spend an entire long weekend  consuming excessive amounts of alcoholic voice lubricants, in order to solve this important aviation conundrum. We never did come up with the answer.

 

That's because you didn't have the internet.

 

A quick google pointed me to a video in which some bloke informed me that they do neither.

 

In fact the fly flies normally near the ceiling, extends its front legs above its head and grasps the ceiling (with a sticky substance secreted on its feet), then uses momentum to flip itself upside down and grasp with the other feet.

 

 

[facthunter]

  Aha...A trick question., Aviation is full of them.. Nev

 

 

[nomadpete]

So, Marty. You're implying that the advent of the internet would have led to a responsible reduction in my alcohol intake, but also hampered my ability to respond to a debate. If that happened, I would have had to wait until I got married to learn the art of debate.

 

Bah, I think it was more fun without Google. Sitting around a campfire comparing Google searches just isn't very challenging.

 

BTW, thanks for the answer.

 

 

[nomadpete]

Thankfully Phil has started a new thread for further discussion of this important aviation conundrum.

 

No doubt someone will be able to tell me how to apply the answers to my next circuit practice.

 

 

[bexrbetter]

Quote/"Does a fly do a half loop or a half roll to land on the ceiling? "

 

When I was a young impressionable bloke, that very question caused a group of us to spend an entire long weekend  consuming excessive amounts of alcoholic voice lubricants, in order to solve this important aviation conundrum. We never did come up with the answer.

 

Next time try: Is ice, water?

 

Another good one: Is milk, a liquid?

 

 

[nomadpete]

Bex. Please.

 

This is an aviation forum!

 

 

[bexrbetter]

Bex. Please.

 

This is an aviation forum!

 

 

 

"Is ice on your wing water"?

 

 

[spacesailor]

ICE is the solid Form of H2O, Steam is another form.

 

Can't be all three at the same Time (instant).

 

spacesailor

 

 

[nomadpete]

Let's see.

 

Wet H2O is water.

 

Steam is water vapour, so it's really not 'water' whilst in a vapour state.

 

But ice.... Nobody calls it water, nor do they call it 'water solid'. Ice is not wet. Only water is wet.....  So as far as language goes, ice is not water until it melts.

 

So there!

 

 

[johnm]

.. dust is mud (with all the water squeezed out)

 

(aeroplanes can get dusty and muddy)

 

 

[kgwilson]

No steam is airborne water droplets just like clouds except it is hot and vaporises to form water vapour as it cools or it will condense to form water that is no longer airborne. Steam is immensely powerful when super heated under pressure. The yanks have still not found anything better to catapult launch their aircraft off carriers.

 

 

[FlyBoy1960]

Well I can walk on water.

 

As long as the lake is frozen.

 

Just amazing

 

 

[old man emu]

 

Actually, the word "nightmare" comes from ancient folklore and writings, where a malicious entity rides on the dreamers chest while they're sleeping.

 

When I was a policeman, I had to deal with the ravages of a family of professional thieves and housebreakers. That mob would steal the saddle off a nightmare.

 

 

[spacesailor]

NO

 

"No steam is airborne water droplets "

 

Super-heated steam 600C is invisible without droplets,

 

And will cut the flesh off the bone.

 

The old "bully-beef" were steers that had their meat removed with high preasure almost super heated steam. (South American production slaughterhouse).

 

They made a film of it & people stopped buying.

 

spacesailor

 

 

[Bruce Tuncks]

Steam can be a vapour or a gas. A vapour can be condensed to a liquid by increasing pressure at constant temperature while a gas can't be. The critical temperature separates the 2. For water, it's about 370 degrees C.

 

Sorry to be so pedantic, I used to teach this stuff in a previous life.

 

My darn spellchecker wants me to spell it vapor because that's the American way.

 

Hey did you hear the true story about the psychics who agreed to be tested by discerning the birth signs of people on the basis of a description of their personality and history?

 

They were correct one time in 12. 

 

 

[facthunter]

Most substances can exist as a solid, a liquid, or a gas and pass from one state to the other as they are heated more. There are exceptions Carbon dioxide (which is a compound) is either solid or gaseous. It's never a liquid.. Hence the name, dry ice. Water vapour is water  molecules suspended in a gas or gases Ie Air which is a mixture of gases. In this case the vapour is invisible. Clouds  are formed of small water droplets which appear as white clouds when viewed from the side where the  light is reflected off them . If the droplets evaporate( get dispersed in the gas) they are no longer visible droplets.  Water can evaporate straight from ice.( Ablate) but it's slow. Evaporation is faster at higher temperatures. Virga is falling rain that evaporates as it falls and doesn't reach the ground. That usually means the air is a very low  relative humidity (as in drought periods like now).  On some changes of state energy is given out( or taken in, in the other direction). With water this is called LATENT heat of vapourisation  and is the energy which sustains Cyclones and makes Cb clouds go so high  and active..Nev

 

 

[old man emu]

Here we are caught in a semantic conflict. Until approximately 350 years ago (give or take) Mankind created words to describe what it observed and dealt with in its daily life. Languages maintained these words and in the case of the chemical scientists identify as H2O, there are many words to describe the way this chemical presents itself.

 

In its solid form it is known as ice, rime, snow. In its liquid form it is known as rain, fog, mist or water. In its gaseous form there is no word, because in this form it is invisible, so Mankind did not make up a word for it.

 

Now "steam" has an interesting etymology. It originated from the Proto-Germanic *staumaz (“steam, vapour, breath”) through Old English stēam (“steam, hot exhalation, hot breath; that which emits vapour; blood”) and Middle English steem, stem. Clearly, this reflects the common experience of people seeing the water vapour in exhaled air condensing as it hits  the atmosphere with a temperature below 4C. The word took on a new meaning in the late 1600's when inventors used the change of phase from gas to liquid to power machines. Calling the engine a "steam" engine reflected this common meaning of visible breath as the condensed gas was visible outside the machine.

 

It has been the scientists, delving and diving into the properties of water who have further defined the states of water so that now, along with invisible gaseous water we have vapour which is a mixture of two phases at room temperature, namely gaseous and liquid phase. A vapour can co-exist with a liquid  when they are in equilibrium state. Therefore from this we can infer that a vapour is a gas state of a substance at a temperature where it can co-exist with its liquid state so for a liquid to become vapour it does not have to first boil. This co-existence of water between liquid and gas is called the vapour pressure of the liquid.

 

 

 

 

[facthunter]

If you want an example of heat being needed/used in the change from liquid to vapour with water look, at how a Coolgardie safe works or how you sweat and cool yourself that way. Boiling point is subject to the existing pressure in the local environment. Like the pressurised radiator cap or the impossibility of getting a hot coffee at altitude, unless the cabin is pressurised. Nev

 

 

[Litespeed]

Do not forget the most Important one to a hot day.

 

Sublimation phase change. This is easiest to demonstrate on a very cold beer, often left in freezer a few minutes to long.

 

Your beer comes out perfectly chilled but on the point of almost changing phase to solid. Now if you tap the bottle the extra energy introduced is sufficient to instantly sublimate and change phase. A tiny amount  of energy, just from the friction of molecules on movement, the gas pressure changes in concert enough to cascade to a solid. Also happens when the pressure drops by opening the bottle or can.

 

This all happens in a few seconds and will form ice which then turns to aerated ice to foamy ice and then just foam and beer as it loses to ambient temp its high speed magic. Its a science  lesson in a perfect cold package.

 

I have a passion for cold cold beer and always love this trick , as long as I have a currently liquid one on hand.

 

The science of vitamin beer.....priceless.

 

Lucky I am dedicated to scientific method. 

 

Off to the laboratory to do more beer........