Ask a physicist anything. (2)

[Wiccan_Child]

Yeah, I figured it'd be something like that. Can't say I've ever done that kind of calculation before.

We had to do it at sixth form, and again in my nuclear physics class. Only this time with mass deficits and the like. Funky stuff.

 

[Cabal]

Francium has a high ioniziation energy because it has a low electronegativity and a huge atomic radius. Basically in solution it's ionic bond will break very easily. This is why hydroiodic acid is considered a stronger acid than hydrofluoric acid. Iodine ionizes more so than fluorine.

I suppose the efficiency of an reaction would be based on its speed and how much of the reactants are used to produce the products. Some reactions even in excess of one reactant will go less than 100% to completion. Others will go to 100% completion.

Do you know what makes the thermite reaction so potent, given that it uses fairly simple reactants?

5lbs of potassium metal into a river

Fire in the hole!

Hey, it could theoretically be done with caesium

We had to do it at sixth form, and again in my nuclear physics class. Only this time with mass deficits and the like. Funky stuff.

Oh sure, pretty sure I've done it with nuclear reactions before - although I guess the principles of doing so are similar to doing so with chemical reactions.

 

[pgp_protector]

You're in a sealed room, their is a scale on the table & a open Jack-In-The-Box.
You have to make the Jack-In-The-Box weigh more.
How can you do this without adding anything to the Jack-In-The-Box?

 

[Cabal]

[BIBLE][/BIBLE]

You're in a sealed room, their is a scale on the table & a open Jack-In-The-Box.
You have to make the Jack-In-The-Box weigh more.
How can you do this without adding anything to the Jack-In-The-Box?

Put it on the scales and starting spinning it in a circle like no tomorrow?

 

[catzrfluffy]

Turn it upside down, wind it up, it pushes the scales down when it springs?

 

[Cabal]

Oooh, ooh, or is this something really psychotic, like:

As the room is sealed, your breathing will replace the O2 in the room with CO2, resulting in a greater "atmospheric" push down on the jack in the box on the scales?

 

[catzrfluffy]

Breathe much, until you replace the heavy oxygen with lighter carbon dioxide? Thus removing air resistance and increasing the weight on the scales.

EDIT: Ah, beat to it.

 

[catzrfluffy]

No. Just sit on the scales.

 

[catzrfluffy]

Use the force Luke...
?

 

[Cabal]

Breathe much, until you replace the heavy oxygen with lighter carbon dioxide? Thus removing air resistance and increasing the weight on the scales.

EDIT: Ah, beat to it.

Actually, I think you did.

Turn it upside down, wind it up, it pushes the scales down when it springs?

 

[Cabal]

I'm going to go with -

Freak out at the realisation you've been sealed in a room with a jack in the box and eviscerate it.

BEFORE IT GETS YOU FIRST

 

[pgp_protector]

Turn it upside down, wind it up, it pushes the scales down when it springs?

Yep
Close it.

That's all you need to do.


Now why??

 

[Cabal]

Man, I'm really indecisive today.

Technically you CAN'T make the jack weigh more as it must have a fixed mass, and you can't add to the mass of the earth altering its gravitational pull and thus the weight of any object in its gravitational field.

Urgh, too much coffee today.

 

[Cabal]

Close it.

....

Ok, my brain just farted.

How does that work?

ETA: Wait, nevermind, you're asking us

Is the scales like a balance? It maybe makes sense to me then - by putting the jack back in the box you might be altering the torque on one pan of the balance which would give you a different result?

 

[canehdianhotstuff]

Closing it a) seals air into it and b) more importantly seals potential energy into the springs which push up on the lid and down on the box pressing it into the scale harder.

 

[Wiccan_Child]

Yep
Close it.

That's all you need to do.


Now why??

Does the act of closing it create extra pressure as the air momentarily pushes down on the box? Or does it seal the air inside, thus causing the air to be part of the box?

 

[Wiccan_Child]

Closing it a) seals air into it and b) more importantly seals potential energy into the springs which push up on the lid and down on the box pressing it into the scale harder.

But the spring wouldn't push down on the scales, it would push the box apart. The scales wouldn't fell anything... would they?

 

[canehdianhotstuff]

To answer the thermite question, aluminum has a much higher affinity to be bound to oxygen than iron does. iron is a high temperature oxidizer and thus takes a high energy input to start which is usually a magnesium strip lit up as a fuse.

 

[pgp_protector]

Closing it a) seals air into it and b) more importantly seals potential energy into the springs which push up on the lid and down on the box pressing it into the scale harder.

a) only if it's air tight, I've not seen one that is yet.
b) true it would add more energy, second part isn't quite right though.

Think of a classic formula now...

 

[Wiccan_Child]

a) only if it's air tight, I've not seen one that is yet.
b) true it would add more energy, second part isn't quite right though.

Think of a classic formula now...

a[sup]2[/sup] = b[sup]2[/sup] + c[sup]2[/sup]?