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Old 19.10.2007, 09:56
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Ask a Scientist

Okay, I'm gonna try this out. Any burning science questions that people would like answered, hopefully me and the other scientists on the forum can answer.

But remember, I'm a chemist, I'm not omniscient. I'll do my best.
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Old 19.10.2007, 09:58
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Re: Ask a Scientist

Hi-
I can help in the field of molecular biology
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Old 19.10.2007, 10:03
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Re: Ask a Scientist

Great idea for a thread!
Since Psychology gets classed as a science - ask away!

But I have one for Chemgoddess:
When you mix Maizena with a certain quantity of water, it has this weird quality of feeling hard and liquid at the same time (try it, you'll be playing for hours, great for kids). Now I'm not sure how to Google this so my question is - how does that work?
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Old 19.10.2007, 10:17
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Re: Ask a Scientist

This one is a job for the chemical engineer... sorry chemgodess, you can have the next one

A cornstarch solution is a type of non-Newtonian fluid, a fluid whose viscosity changes with shear.

In the case of a mixture of cornstarch and water, the viscosity increases with the shear rate - so it gets harder the more you stir. This is known as a dilatant material.

The opposite (viscosity decreases with shear) is a pseudoplastic material. A common example of this is tomato sauce - we all know how hard is getting that stuff out of a bottle, but once it starts moving, you can't stop it.
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Old 19.10.2007, 10:28
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Re: Ask a Scientist

If the Universe is expanding, where or what is it expanding into?

I've seen an episode of Heroes and want to develop my ESP. Any tips?

One more: why doesn't the Earth's gravitational force provide / allow a constant law regarding hydrodynamics? It's complicated and I need an idiots guide. Thanks for any feedback.
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Old 19.10.2007, 10:33
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Re: Ask a Scientist

I have one: You're boiling water to cook pasta. When the water gets hot enough to add oil and salt, why does the water start boiling like crazy right when you add the salt?


(someone said there are no dumb questions)
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Old 19.10.2007, 10:34
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Re: Ask a Scientist

Brilliant idea for a thread. Will have to ask some of my nuclear physics friends if they have any decent questions to ask!!
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Old 19.10.2007, 11:19
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Re: Ask a Scientist

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If the Universe is expanding, where or what is it expanding into?
Technically, the answer is "nothing". I guess it depends on which theory du jour you subscribe. Hyperspace theory claims that the instant before the big bang, a 10-dimension space decayed into 2 "pieces", of which:
1) one piece expanded into an infinite 4-dimension macro space in which our universe is expanding
2) the other piece contracted/collapsed into an infinitesimal 6-dimension space about the size of the Planck length.

Last edited by bozothedeathmachine; 19.10.2007 at 11:21. Reason: Spelling
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Old 20.10.2007, 15:34
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Re: Ask a Scientist

My understanding is that the "expanding" is not in the sense of a bubble expanding. So, if you want to think about it while in 3D/4D, then the curvature of space is slowly changing with time. By analogy, if Earth was expanding very slowly you would not notice much. But in the very long term your neighbor would end up living a little further away from you.

[quote=Uncle Max;118450]If the Universe is expanding, where or what is it expanding into?
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Old 19.10.2007, 10:33
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Re: Ask a Scientist

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This one is a job for the chemical engineer... sorry chemgodess, you can have the next one

A cornstarch solution is a type of non-Newtonian fluid, a fluid whose viscosity changes with shear.

In the case of a mixture of cornstarch and water, the viscosity increases with the shear rate - so it gets harder the more you stir. This is known as a dilatant material.

The opposite (viscosity decreases with shear) is a pseudoplastic material. A common example of this is tomato sauce - we all know how hard is getting that stuff out of a bottle, but once it starts moving, you can't stop it.
The word which describes these processes is nice. Try to fit it into daily conversation: thixotropy or thixotropic
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Old 19.10.2007, 10:34
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Re: Ask a Scientist

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This one is a job for the chemical engineer... sorry chemgodess, you can have the next one

A cornstarch solution is a type of non-Newtonian fluid, a fluid whose viscosity changes with shear.

In the case of a mixture of cornstarch and water, the viscosity increases with the shear rate - so it gets harder the more you stir. This is known as a dilatant material.

The opposite (viscosity decreases with shear) is a pseudoplastic material. A common example of this is tomato sauce - we all know how hard is getting that stuff out of a bottle, but once it starts moving, you can't stop it.
Woooow *think wow like those little green alien toys did in Toy Story II*, I feel like my IQ has just gone up five points.

As for the universe, that's a tough one, as there is actually nothing outside of the universe. I find this totally unfathomable and explain this shortcoming with the fact, that my brain has boundaries given by the skull it lives in.

But if you want a really good explanation for that, I recommend Bill Bryson's Short History of Nearly Everything, also available as an audiobook and a brilliant read for people who like simple explanations for complex things.
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Old 12.01.2013, 16:08
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Re: Ask a Scientist

Isn't car also burning more gas when running fast pace?

I think metabolism isn't so regular, though, the min your body gets used to routine, your fast pace burning will change and you will have to alternate, circuit or run faster in order to burn as much.
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Old 12.01.2013, 22:39
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Re: Ask a Scientist

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Isn't car also burning more gas when running fast pace?

I think metabolism isn't so regular, though, the min your body gets used to routine, your fast pace burning will change and you will have to alternate, circuit or run faster in order to burn as much.
re. cars Yes it does, but that's because of drag, which increases faster than speed at high speeds. So that factor is not relevant for running.

Although part of the improvement in performance caused by training is due to higher efficiency, mainly it is due to gaining a capacity to use more energy (more enzymes in the muscles, better oxygen throughput...). So top athletes can burn more energy than the untrained.
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Old 22.01.2013, 07:03
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Re: Ask a Scientist

Here are my questions.

When viewed through a telescope far worlds are seen as they were 1,10,100,1000 light years ago. Assuming that a telescope is so powerful that a family can be seen having a picnic on one of those far star's planets (all those light years ago), how is it if I could travel at such an extraordinary speed that I could catch up and pass light before the light from the time of my birth on this planet reaches me - would I then, when the light catches me up, then be able, at the due time, to see myself being born?

Does light travel in one direction or go everywhere at the same speed?

If light shows us what happened in the past, as above, could we see the Big Bang?

And finally; assuming that all this is possible then it would appear that everything that's happened everywhere in the universe, is, under the assumption that the speed of light could be overtaken, still visible to an observer - so when does it stop being visible to an observer who fulfills the requirements?
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Old 22.01.2013, 10:34
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Re: Ask a Scientist

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Here are my questions.

When viewed through a telescope far worlds are seen as they were 1,10,100,1000 light years ago. Assuming that a telescope is so powerful that a family can be seen having a picnic on one of those far star's planets (all those light years ago), how is it if I could travel at such an extraordinary speed that I could catch up and pass light before the light from the time of my birth on this planet reaches me - would I then, when the light catches me up, then be able, at the due time, to see myself being born?

Does light travel in one direction or go everywhere at the same speed?

If light shows us what happened in the past, as above, could we see the Big Bang?

And finally; assuming that all this is possible then it would appear that everything that's happened everywhere in the universe, is, under the assumption that the speed of light could be overtaken, still visible to an observer - so when does it stop being visible to an observer who fulfills the requirements?
A lot of questions. I'm not a scientist but read up on this stuff (to the limit of my ability to understand!) a while ago.

Your first issue of seeing yourself born is "solved" by hard limits to the speed you can travel at. You can't travel faster than the speed of light. If you did, you would be going "back in time" (at your point of observation) and hence yes, would see yourself being born.

This isn't too different to severely "slowing down the speed of light" by, for example, videoing your birth and watching the replay You're not existing before you were born, just watching it.

Could you see the big bang? Well, by observing stars we're looking at them at the point in time when the light (that we use to see them) left the star. So in order to see the big bang we'd need to see a light generating object that existed right at that point. So we can only see as far back as to when light existed. Of course, we can build detectors that register other particles, so a detector could "see" further back than we can with our eyes, but again we need to actually detect one of those particles. Now, these particles travel at the speed of light so if they were emitted at the big bang point itself, they are now at the far edge of the universe and we've already missed our opportunity to detect them. So we could only measure them from left over interactions that are in their path of travel.

Light is carried by photons (a dual wave/particle entity) and has direction. Photons are generated when energy is released from an atom when its energy state changes (an electron moves orbit after having previous been "excited" into a higher energy state). More photons, more ligth spread. Plus the speed of light is as it is when travelling in a vacuum (a vacuum being what we consider to be empty space, which is probably totally full of things we don't understand such as the Higgs field and dark energy/matter) and is slowed down when going through objects (objects which don't actually block or reflect the photon) such as glass.

If you could travel faster than the speed of light and can overtake it (and hence get outside the boundary of the universe to see the big bang remnants) then yes, you could travel around seeing everything which happened. But as faster than light travel isn't possible*, the question doesn't come up. *Maybe it is, but only for particles which have no mass. So you'd need to go on a diet.
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Old 22.01.2013, 11:12
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Re: Ask a Scientist

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Here are my questions.

When viewed through a telescope far worlds are seen as they were 1,10,100,1000 light years ago. Assuming that a telescope is so powerful that a family can be seen having a picnic on one of those far star's planets (all those light years ago), how is it if I could travel at such an extraordinary speed that I could catch up and pass light before the light from the time of my birth on this planet reaches me - would I then, when the light catches me up, then be able, at the due time, to see myself being born?

Does light travel in one direction or go everywhere at the same speed?

If light shows us what happened in the past, as above, could we see the Big Bang?

And finally; assuming that all this is possible then it would appear that everything that's happened everywhere in the universe, is, under the assumption that the speed of light could be overtaken, still visible to an observer - so when does it stop being visible to an observer who fulfills the requirements?
Time Dilation

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In theory, and to make a clearer example, time dilation could affect planned meetings for astronauts with advanced technologies and greater travel speeds. The astronauts would have to set their clocks to count exactly 80 years, whereas mission control—back on Earth—might need to count 81 years. The astronauts would return to Earth, after their mission, having aged one year less than the people staying on Earth. What is more, the local experience of time passing never actually changes for anyone. In other words, the astronauts on the ship as well as the mission control crew on Earth each feel normal, despite the effects of time dilation (ie. to the traveling party, those stationary are living "faster"; whilst to those stood still, their counterparts in motion live "slower" at any given moment).
Yes, it gets complicated.... and no I don't really understand it.
I just remember this from Physics at school (which was a long time ago)

But yes, adrianlondon is quite correct, time is linked to the speed of light.
An Astronaut who go into space with synchronised watches will have a slightly faster time with mission control when they land.
(It's bugger all, but it has been measured).

The faster you travel the slower time becomes. Faster than the speed of light and time would move backwards.....

If you observed a telescope on another planet and it was observing you, and let's say that you could speed faster than the speed of light towards the other telescope and look through it....... you would see yourself approaching the telescope you are looking through.
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Old 19.10.2007, 11:57
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Re: Ask a Scientist

How do tetraneutrons exist?
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Old 19.10.2007, 12:00
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Re: Ask a Scientist

Hasn't been proven that they do.

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How do tetraneutrons exist?
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Old 19.10.2007, 12:01
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Re: Ask a Scientist

If fusion at room temperature is deemed impossible by every accepted scientific theory, explain the existance of Cold Fusion?
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Old 19.10.2007, 13:19
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Re: Ask a Scientist

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If fusion at room temperature is deemed impossible by every accepted scientific theory, explain the existance of Cold Fusion?
That's easy. It doesn't exist, as we understand it anyway. Go ask Pons & Fleischmann. But the definition of a "breakthrough" is one that "breaks through" every accepted scientific theory, as you put it. Go ask Einstein about that one.
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