Post your science questions here!

seedywagon · 08-09-2012, 11:55 PM

Hi everyone,
I'm not sure if this has been done before, but I'd like to start a thread that provides the opportunity to ask ANY question that is science-related.
So, if you need something explained, or if you have a great explanation for somebody else's question, don't hold back!
Science is a constant journey of discovery, and with the rate of interest in science-related careers dropping, I think it's good to re-invigorate some curiosity as to how this amazing world ticks.

MITCHAY · 09-09-2012, 12:09 AM

Cool idea. Another thing would be to post some interesting facts as well as post questions.

BHDOGS · 09-09-2012, 12:13 AM

Why does the center of the galaxy and the edge spin at the same speed?

seedywagon · 09-09-2012, 12:29 AM

Quote:

Originally Posted by BHDOGS

Why does the center of the galaxy and the edge spin at the same speed?

This is a tricky one, but from what I've read, the velocity of particles 'spinning' in the milky way actually vary depending on distance from it's centre, with particles closer in spinning slightly quicker, but not by much. I think it would have to do with the physics involved when it was actually created, in space, where Newton's law of inertia is king.
My guess is that at its birth, whatever force that caused it to spin in the first place must have been so vast, it was able to accelerate everything in its way at roughly the same rate, and being space, there wasn't much to slow any of it down.

BHDOGS · 09-09-2012, 12:08 PM

Quote:

Originally Posted by seedywagon

This is a tricky one, but from what I've read, the velocity of particles 'spinning' in the milky way actually vary depending on distance from it's centre, with particles closer in spinning slightly quicker, but not by much. I think it would have to do with the physics involved when it was actually created, in space, where Newton's law of inertia is king.
My guess is that at its birth, whatever force that caused it to spin in the first place must have been so vast, it was able to accelerate everything in its way at roughly the same rate, and being space, there wasn't much to slow any of it down.

So really nobody knows haha

seedywagon · 09-09-2012, 05:04 PM

Quote:

Originally Posted by BHDOGS

So really nobody knows haha

Probably not, but it's a good question.

2011G6E · 09-09-2012, 08:45 PM

Quote:

Originally Posted by BHDOGS

Why does the center of the galaxy and the edge spin at the same speed?

It doesn't...that's why it's a spiral instead of just a big spinning disc.

I love the "why are there still apes" evolution question...people assumed that "we evolved from monkeys". No we didn't. We evolved from a common ape-like hominid ancestor. Monkeys, gorillas, chimps, etc, all took one path, humans took another with plenty of dead-end offshoots that ended up with us.

Dogs, cats, all the apes and monkeys, and every animal we see isn't "incomplete" or "unevolved"...they are all the end result of an equally long evolutionary process as our species has been through, they are all equally advanced animals as we are, it's just they turned out like they did, and by a stroke of luck we turned out like we did. There's no rule that said we had to evolve intelligence of our level, it was an accident of evolution.

Quote:

Originally Posted by XARATE

Why doesnt glue stick to the inside of the bottle?

It does...the cap being on keeps the glue from setting and pretty much in a liquid state. Above the level of the glue is a fine layer of dried glue which can only really develop when a bottle sits for a while after being used.

Quote:

Originally Posted by ute83

Why doesn't the sun blow up?

Oh it will one day. At this stage of it's life, the pressure of the fusion reactions pushing outwards are just about equalled by the gravity of the mass of the star pulling inwards. When it consumes enough hydrogen and converts it into helium, it will start collapsing, working it's way down to iron burning, and that's pretty much it. Our star isn't big enough to "blow up" in a supernova, but it will collapse down and blow off shells of gas as it does after going through a stage of expansion as the reactions inside overcome the gravity of it's mass. It will expand as far as Earth or maybe more as a red giant, then collapse back down to a white dwarf.

XR6T0Y · 09-09-2012, 10:54 PM

Quote:

Originally Posted by 2011G6E

Oh it will one day. At this stage of it's life, the pressure of the fusion reactions pushing outwards are just about equalled by the gravity of the mass of the star pulling inwards. When it consumes enough hydrogen and converts it into helium, it will start collapsing, working it's way down to iron burning, and that's pretty much it. Our star isn't big enough to "blow up" in a supernova, but it will collapse down and blow off shells of gas as it does after going through a stage of expansion as the reactions inside overcome the gravity of it's mass. It will expand as far as Earth or maybe more as a red giant, then collapse back down to a white dwarf.

I was taught this very different.
The way I knew it was.... The sun WILL blow up in a supernova. Not for many millions, if not billions of years. However, there will be no life left on Earth when it happens. Why? Because as the sun gets older, it expands. It will reach a point where it expands to much, and will wipe out Earth and life due to simple temperature (it will encapsulate [spelling?] everything effectively) before breaking its own bounds and exploding. Leaving no life in existance (for our Galaxy/Solar system anyways)

MWTB · 09-09-2012, 11:00 PM

Quote:

Originally Posted by XR6T0Y

I was taught this very different.
The way I knew it was.... The sun WILL blow up in a supernova. Not for many millions, if not billions of years. However, there will be no life left on Earth when it happens. Why? Because as the sun gets older, it expands. It will reach a point where it expands to much, and will wipe out Earth and life due to simple temperature (it will encapsulate [spelling?] everything effectively) before breaking its own bounds and exploding. Leaving no life in existance (for our Galaxy/Solar system anyways)

And moments before this happens, Super Massive Black Hole by Muse will echo throughout the universe.

BHDOGS · 10-09-2012, 12:09 AM

[QUOTE=2011G6E]It doesn't...that's why it's a spiral instead of just a big spinning disc. [QUOTE=2011G6E]

Um no they rotate at practicly the same speed

XRDeeze · 10-09-2012, 03:45 PM

Quote:

Originally Posted by 2011G6E

There's no rule that said we had to evolve intelligence of our level, it was an accident of evolution.

flappist · 10-09-2012, 04:47 PM

Quote:

Originally Posted by XRDeeze

image

Absolutely correct.

The evolution of life on earth over the last 100,000,000 years or so was an experiment by aliens who come to visit occasionally to see how we are going.

Unfortunately a couple of thousand years ago a practical joke was played which has been a source of amusement for them ever since.........

XR6T0Y · 09-09-2012, 12:22 AM

What's the meaning of life

seedywagon · 09-09-2012, 12:31 AM

Quote:

Originally Posted by XR6T0Y

What's the meaning of life

I knew this wouldn't take long :p

XP6 · 09-09-2012, 09:33 PM

Originally Posted by XR6T0Y
What's the meaning of life

Quote:

Originally Posted by seedywagon

I knew this wouldn't take long :p

Is the glass half full or half empty...

I always answer just to be ****

, neither the glass is always full

Chopped · 09-09-2012, 09:54 PM

When will science know 100% what it is talking about ?

Vincenzo · 09-09-2012, 02:33 AM

Quote:

Originally Posted by XR6T0Y

What's the meaning of life

Answer = 42 Check with the Monty Python boys.

This is my one and only scientific statement repeated from an unknown source

HELL EXPLAINED BY A CHEMISTRY STUDENT

The following is an actual question given on a University of *Washington *chemistry mid-term exam.

The answer by one student was so 'profound' that the professor shared it with colleagues, via the Internet, which is, of course, why we now have the pleasure of enjoying it as well :

Bonus Question: Is Hell exothermic (gives off heat) or endothermic (absorbs heat)?

Most of the students wrote proofs of their beliefs using Boyle's Law (gas cools when it expands and heats when it is compressed) or some variant.

One student, however, wrote the following:

First, we need to know how the mass of Hell is changing in time. So we need to know the rate at which souls are moving into Hell and the rate at which they are leaving. I think that we can safely assume that once a soul gets to Hell, it will not leave. Therefore, no souls are leaving. As for how many souls are entering Hell, let's look at the different religions that exist in the world today.

Most of these religions state that if you are not a member of their religion, you will go to Hell. Since there is more than one of these religions and since people do not belong to more than one religion, we can project that all souls go to Hell. With birth and death rates as they are, we can expect the number of souls in Hell to increase exponentially.

Now, we look at the rate of change of the volume in Hell because Boyle's Law states that in order for the temperature and pressure in Hell to stay the same, the volume of Hell has to expand proportionately as souls are added.

This gives two possibilities:

1. If Hell is expanding at a slower rate than the rate at which souls enter Hell, then the temperature and pressure in Hell will increase until all Hell breaks loose.

2. If Hell is expanding at a rate faster than the increase of souls in Hell, then the temperature and pressure will drop until Hell freezes over.

So which is it?

If we accept the postulate given to me by Teresa during my Freshman year that, 'It will be a cold day in Hell before I sleep with you,' and take into account the fact that I slept with her last night, then number two must be true, and thus I am sure that Hell is exothermic and has already frozen over.

The corollary of this theory is that since Hell has frozen over, it follows that it is not accepting any more souls and is therefore, extinct ...... leaving only Heaven, thereby proving the existence of a divine being which explains why, last night, Teresa kept shouting 'Oh myyyyyy God.'

THIS STUDENT RECEIVED AN A+.

Ducati888 · 09-09-2012, 11:00 AM

Quote:

Originally Posted by Vincenzo

Answer = 42 Check with the Monty Python boys.

Not Monty Python. It was Douglas Adams, from Hitchhiker's Guide to the Galaxy.

For all your science questions and more ( and I guarantee you that everything discussed so far in this thread has been covered here) go to the ABC's Self Service Science Forum.

There are no science related answers you can't get there.

http://www.abcforums.com/forum.php?

burnz · 10-09-2012, 05:20 AM

Quote:

Originally Posted by XR6T0Y

What's the meaning of life

thats easy..
the meaning of life is one's own perspective.

MITCHAY · 09-09-2012, 12:32 AM

A little party trick I used to do was to drop a 5c coin and a 50c coin at the same height and get people to bet which one landed first. Then mix up the heights with the same results.

seedywagon · 09-09-2012, 12:36 AM

Quote:

Originally Posted by MITCHAY

A little party trick I used to do was to drop a 5c coin and a 50c coin at the same height and get people to bet which one landed first. Then mix up the heights with the same results.

Yay! Acceleration due to gravity does not change depending on mass, it is and always will be 9.8 metres per second squared.

foxtrot3 · 09-09-2012, 08:59 PM

Quote:

Originally Posted by seedywagon

Yay! Acceleration due to gravity does not change depending on mass, it is and always will be 9.8 metres per second squared.

Hi. when I did science acceleration was 9.8 metres per second per second. What changed. Cheers MD

XR6T0Y · 09-09-2012, 12:37 AM

Quote:

Originally Posted by MITCHAY

A little party trick I used to do was to drop a 5c coin and a 50c coin at the same height and get people to bet which one landed first. Then mix up the heights with the same results.

I've heard that if you drop two things (with wind factor taken out) froma decent height, no matter the weight or shape they will fall at the same speed?

Quote:

Originally Posted by seedywagon

I knew this wouldn't take long :p

Was being serious to

Madaya · 09-09-2012, 12:42 AM

Check out this You Tube vid. An experiment by Dave Scott, commander of Apollo 15. Very cool.....

http://www.youtube.com/watch?v=KDp1tiUsZw8

seedywagon · 09-09-2012, 12:43 AM

Quote:

Originally Posted by XR6T0Y

I've heard that if you drop two things (with wind factor taken out) froma decent height, no matter the weight or shape they will fall at the same speed?

They'd be correct, with air resistance out of the picture, objects fall at equal rates in free fall.

Was being serious to

Science can theoretically only provide a partial answer to this question I reckon, the other half would be the domain of philosophers and philologers. Einstein tried to find an equation to explain everything in the universe with questionable success.

MITCHAY · 09-09-2012, 12:44 AM

Quote:

Originally Posted by XR6T0Y

I've heard that if you drop two things (with wind factor taken out) froma decent height, no matter the weight or shape they will fall at the same speed?

Was being serious to

Quote:

Originally Posted by seedywagon

Yay! Acceleration due to gravity does not change depending on mass, it is and always will be 9.8 metres per second squared.

Yep of course the only exception is resistance. Obviously a feather and a brick won't land the same time but most things will. My mate used to trip balls over it.

Ducati888 · 09-09-2012, 10:53 AM

Quote:

Originally Posted by MITCHAY

Yep of course the only exception is resistance. Obviously a feather and a brick won't land the same time but most things will. My mate used to trip balls over it.

No exceptions. Items will fall at the same rate in a vaccuum. Feather or brick or elephant. It's not a theory it's a fact. Mass is irrelevant.

The equations and tests are pertinent to a perfect vaccuum only.

jaydee · 09-09-2012, 12:40 AM

If you are flogging through space in your space ship at night at light speed and turn on your headlights, will you be able to see where you're going?

seedywagon · 09-09-2012, 12:49 AM

Quote:

Originally Posted by jaydee

If you are flogging through space in your space ship at night at light speed and turn on your headlights, will you be able to see where you're going?

Due to Einsteins theory of relativity, which he spent ages developing based on a very similar question to what you just asked, my logic would say no, because you're travelling at the same speed as the light you're trying to emit, therefore the light beam from your headlights must accelerate faster than your spaceship in order to 'break free' of it.

XR6T0Y · 09-09-2012, 12:50 AM

Quote:

Originally Posted by seedywagon

Due to Einsteins theory of relativity, which he spent ages developing based on a very similar question to what you just asked, my logic would say no, because you're travelling at the same speed as the light you're trying to emit, therefore the light beam from your headlights must accelerate faster than your spaceship in order to 'break free' of it.

But if you're travelling at the speed of light, wouldn't the light beams then travel twice as fast as the speed of light? As to it, it would still be in a stationary position travelling at light speed