Science Quiz

sprinkles said:
[MENTION=10252]say what[/MENTION]
I think I figured it out.

Blue is easy to distinguish, but it is not the strongest color for contrast or carrying over a distance which is important at night.

So I think the taxiway lights are blue so that if you can see the blue, you easily know that ISN'T the runway because blue is not used on the runway. But for finding the runway, yellow is probably better.
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Thanks [MENTION=6917]sprinkles[/MENTION]!!

I've actually been trying to find a source for it- but couldn't, although...I did read a pilot's guide to Australian runways!!
 
Eventhorizon said:
When we look at the universe in infra-red, we can see through dust clouds, nebula etc... I have to assume the longer wave lengths reds, orange, yellows make it easier to see the light through fog and clouds than it would be with the shorter ones like blue. Not a statement of fact, just a guess.
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I think this is awesome!!

http://www.aoa.org/optometrists/tools-and-resources/clinical-care-publications/aviation-vision/the-eye-and-night-vision

This is an article that talks about night visions, and how we can see different waves of light. Kind of neat- I like the 'black hole' vision.


Additionally...it's written for flight surgeons....HOW COOL OF A JOB DOES THAT SOUND LIKE??
 
Here are some more from their archive!

1. When children blow bubbles, why are they always spherical?

2. How do cats purr?

3. When Mount St Helens erupted, the explosion was equivalent to millions of tonnes of explosives. Yet, the noise was not heard within 100k of the volcano. Why not?

4. How do ducks stay warm?

I know the answers to these...but these two don't have the answers posted! So guess away if you like :)

a. If you run a tap, and put an object in the sink near the flowing water, the stream will migrate to, and eventually over, the object. Why?

b. How is it that water can drop below the freezing point and not freeze?
 
1. A sphere provides the smallest surface area that maintains equilibrium between the inside contents and outside contents without breaking the surface tension. A floating bubble will wobble but will tend to want to go back to being spherical to equalize all the forces acting on it in every direction. Unequal forces will distort the bubble.

2. I don't know but I'm glad they do!

3. The explosion blew away the air quickly enough to limit the sound travel. The air blew literally blew up and took a lot of the sound with it so that it couldn't travel quite as far. Sounds waves are mechanical waves and require a medium to pass through, so if you move the medium fast enough, the sound goes with it. Or if the explosion created a vacuum, that could do it too.

It's like if you took a playing radio and launched it, the sound goes away because it takes the sound waves with it. The reverse can happen if you somehow launch the air away from the radio.

4. LOVE BECAUSE DUCKS ARE AWESOME

a. I don't remember and I'm lazy right now. I will look this up later though because I want to know.

b. It is supercooled without impurities or imperfections to form ice crystals around. If you throw something into that water though it is going to freeze.
 
say what said:
But it's a constant flow of water out of the pump, the surge comes from the pressure of the water falling back and compressing the water - like a plug....it's like a cycle, because once there is enouch internal pressure, it pushes the water plug back out and up, which again falls back and starts the process again. Because they state that it's a constant flow, I think they're not asking about the functions of the pump, and more on the process of water flow.
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I'm not going to deny it. I don't know enough about it. Still not convinced! =) Still would like to see that done with gravity feed.
 
say what said:
Here are some more from their archive!

1. When children blow bubbles, why are they always spherical?

2. How do cats purr?

3. When Mount St Helens erupted, the explosion was equivalent to millions of tonnes of explosives. Yet, the noise was not heard within 100k of the volcano. Why not?

4. How do ducks stay warm?

I know the answers to these...but these two don't have the answers posted! So guess away if you like :)

a. If you run a tap, and put an object in the sink near the flowing water, the stream will migrate to, and eventually over, the object. Why?

b. How is it that water can drop below the freezing point and not freeze?
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1) sphere: most volume, least surface area! i think tendency to enclose the most volume in the least surface area is the reasoning on this one..

2)They use the Force

3)energy was release underground -muffled?

4)same way I do! down! their feathers keep water off their body and the downy one trap enough dead air space to insulate

A)convection cell Technically, I don't think convection cell describes the phenomena correctly but in spirit, same thing

B)frozen water is a crystalline structure. Supercooled liquid water never started building crystals.
 
sprinkles said:
3. The explosion blew away the air quickly enough to limit the sound travel. The air blew literally blew up and took a lot of the sound with it so that it couldn't travel quite as far. Sounds waves are mechanical waves and require a medium to pass through, so if you move the medium fast enough, the sound goes with it. Or if the explosion created a vacuum, that could do it too.
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You rock. Thought about that and i was weird about it. Seems like the initial shockwave could be heard though.

Within? is that the right word? Like, if you were really close, you didn't hear it?

I got it!!! heat. spread apart the molecules too much to do compression waves.
 
Rift Zone said:
You rock. Thought about that and i was weird about it. Seems like the initial shockwave could be heard though.

Within? is that the right word? Like, if you were really close, you didn't hear it?

I got it!!! heat. spread apart the molecules too much to do compression waves.
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Well yes some of the sound will be heard through the ground but sound slows down a lot more through solids. The air also wouldn't throw away all the sound completely so some would travel through the air, just significantly less than normal.

Think that from a volcano, the quickest way for energy to escape is straight up. So that would push the air straight up, carrying the sound waves riding in that air and gradually dispersing them into the sky as the air moves up while releasing its sound wave energy at the same time rather than along the ground as usual.

Edit:
Actually I got that backwards. Sound travels faster in solids. But the structure of solids can dampen and absorb it depending on the solid.

This is why we check! :P
 
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sprinkles said:
Well yes some of the sound will be heard through the ground but sound slows down a lot more through solids. The air also wouldn't throw away all the sound completely so some would travel through the air, just significantly less than normal.

Think that from a volcano, the quickest way for energy to escape is straight up. So that would push the air straight up, carrying the sound waves riding in that air and gradually dispersing them into the sky as the air moves up while releasing its sound wave energy at the same time rather than along the ground as usual.

Edit:
Actually I got that backwards. Sound travels faster in solids. But the structure of solids can dampen and absorb it depending on the solid.

This is why we check! :P
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Nice! i saw that and was like, umm. Ya, more density, more tightly packed, more effective compression waves move because individual atoms/molecules need not travel so far to affect their neighbor.

The muffled answer i gave at first is flawed. So is the got blown away argument -compression wave. Your got taken away approach, dragged up with the flow approach... I don't see that being it either.



It blew off half a mountain. and I doubt getting caught up in the explosion accelerated the local air to mach 1 toward ground zero. I'm gonna stick with heat. that made a huge noise!!! -compression waves, whatever. But it wouldn't transmute if the air were too thin. Lost in the ambient motion is my answer.
 
Rift Zone said:
Nice! i saw that and was like, umm. Ya, more density, more tightly packed, more effective compression waves move because individual atoms/molecules need not travel so far to affect their neighbor.

The muffled answer i gave at first is flawed. So is the got blown away argument -compression wave. Your got taken away approach, dragged up with the flow approach... I don't see that being it either.



It blew off half a mountain. and I doubt getting caught up in the explosion accelerated the local air to mach 1 toward ground zero. I'm gonna stick with heat. that made a huge noise!!! -compression waves, whatever. But it wouldn't transmute if the air were too thin. Lost in the ambient motion is my answer.
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Yeah that's another possibility.

However explosive compression waves are fully capable of pushing air 'faster than sound'. Not only does it push the air but rapidly overpressurizes it.

It doesn't mean a lot to say "Mach 1" or "faster than sound" because the property of sound is dependent on the compression of the medium. Mach 1 is not a fixed speed, it is actually a ratio, and the ground speed of any given mach number can differ depending on the atmosphere the object is moving through.

So while you may or may not be on track, and I could be wrong, it's still plausible either way. Thin air from heat could do it and so could a massive pressure wave.
 
sprinkles said:
Yeah that's another possibility.

However explosive compression waves are fully capable of pushing air 'faster than sound'. Not only does it push the air but rapidly overpressurizes it.

It doesn't mean a lot to say "Mach 1" or "faster than sound" because the property of sound is dependent on the compression of the medium. Mach 1 is not a fixed speed, it is actually a ratio, and the ground speed of any given mach number can differ depending on the atmosphere the object is moving through.

So while you may or may not be on track, and I could be wrong, it's still plausible either way. Thin air from heat could do it and so could a massive pressure wave.
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Sure! Explosive compression waves are fully capable of pushing air 'faster than sound'. -But that's radially outward, the reverse of your most recent proposal. And even if the initial shockwave scattered sound within it's volume, we would hear that initial shockwave.

I suppose there could be another explanation, but I'm not coming up with much. Heat death fits pretty good.

Mach one is defined as the speed of sound through our atmosphere, at sea level... Moisture content can vary as much as 4%... That changes density & rate of compression transmution. Anyway, think i was using the term right.
 
Rift Zone said:
Sure! Explosive compression waves are fully capable of pushing air 'faster than sound'. -But that's radially outward, the reverse of your most recent proposal. And even if the initial shockwave scattered sound within it's volume, we would hear that initial shockwave.

I suppose there could be another explanation, but I'm not coming up with much. Heat death fits pretty good.

Mach one is defined as the speed of sound through our atmosphere, at sea level... Moisture content can vary as much as 4%... That changes density & rate of compression transmution. Anyway, think i was using the term right.
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Sure it is radial but not perfectly radial. It's not the case that the explosion wasn't heard at all.

There's a phenomenon called mach stem where pressure bounces off the surface and goes back to amplify the blast wave in another direction. If mach stem bounces off the ground, it is still slightly radial but the bounce reflects the shock predominantly upwards rather than along the ground. The area with greatest pressure is directly above and the least is directly to the sides.

Also Mach number = relative speed divided by speed of sound in the medium.

So Mach 1 is not the speed of sound at sea level. It is the speed of the object divided by the speed of sound at any level. The speed of sound at sea level is the speed of sound at sea level.

Edit:
Actually what I said about mach stem was wrong. Scratch that.

This is why I don't do this. I give up. I'd rather actually know what I'm talking about than make conjectures.
 
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[MENTION=10252]say what[/MENTION]
You are basically reproducing through heat and cooking what nature does naturally through the ripening process.
If you do it wrong then the result will not be soft sweet flesh that you expect to have.
@sprinkles had it right with the osmosis comment.
You are basically diluting the cells liquid content with the water they are poached in, whereas the water content would be so diluted that it would be barely detectable to the tongue.
This is why you usually add sugar to the water when poaching fruit.
(I graduated Chef School before I mixed up in the medical field...lol)
 
sprinkles said:
Sure it is radial but not perfectly radial. It's not the case that the explosion wasn't heard at all.

There's a phenomenon called mach stem where pressure bounces off the surface and goes back to amplify the blast wave in another direction. If mach stem bounces off the ground, it is still slightly radial but the bounce reflects the shock predominantly upwards rather than along the ground. The area with greatest pressure is directly above and the least is directly to the sides.

Also Mach number = relative speed divided by speed of sound in the medium.

So Mach 1 is not the speed of sound at sea level. It is the speed of the object divided by the speed of sound at any level. The speed of sound at sea level is the speed of sound at sea level.
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Mach stem seems like it would cause even more noise.

I had to look up Mach to see how it was defined. You are right. It's defined by sound (compression wave) propagation speed where it is at the time, not against sea level.
 
Rift Zone said:
Mach stem seems like it would cause even more noise.

I had to look up Mach to see how it was defined. You are right. It's defined by sound (compression wave) propagation speed where it is at the time, not against sea level.
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Yeah. I was wrong about mach stem. Being to the side would be the worst place to be because all the pressure fronts meet up there.

I'm going to stop getting ahead of myself. At least I'm learning but I think this is the wrong way for me to do it.
 
I guess I should clarify that this is a segment on a morning radio show! So the answers are generally simplified! As long as you guys are having fun, I'll post them! :) but hopefully the answers don't disappoint, because so far you guys have been giving way better answers than he normally gives!! :D
 
1. When children blow bubbles, why are they always spherical? Because children arent sperical

2. How do cats purr? No one knows. Why would they ask a question that has eluded people since the dawn of time and cats?

3. When Mount St Helens erupted, the explosion was equivalent to millions of tonnes of explosives. Yet, the noise was not heard within 100k of the volcano. Why not? Volcanic Dust muffled noise?

4. How do ducks stay warm? Down.

I know the answers to these...but these two don't have the answers posted! So guess away if you like :)

a. If you run a tap, and put an object in the sink near the flowing water, the stream will migrate to, and eventually over, the object. Why? Decreased air pressure. Like a plane wing

b. How is it that water can drop below the freezing point and not freeze?[/QUOTE] Material in water. Keeps water from crystallizing.

I dont like the cat question. Not at all. Its a trick question.
 
say what said:
I guess I should clarify that this is a segment on a morning radio show! So the answers are generally simplified! As long as you guys are having fun, I'll post them! :) but hopefully the answers don't disappoint, because so far you guys have been giving way better answers than he normally gives!! :D
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It's fine. I believe insightful answers that illustrate some understanding are better than completely wrong ones.

However after the google thing I started trying to show off and that's not something I should be doing. I don't ordinarily try to prove how smart I am. And even though it isn't serious, I don't want to get in the habit of misinforming people just to make myself look good.

If I make a mistake that's one thing but if I try to be showy and get it wrong when I should have known how much I don't actually know, then that's being kind of dumb on my part.
 
Eventhorizon said:
2. How do cats purr? No one knows. Why would they ask a question that has eluded people since the dawn of time and cats?
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They know how they purr, they just don't exactly know why!
 
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