Science & Technology Quiz 2: The one with the catchy title.

[Perfection]

Why bother convertine from Celsius to Fahrenheit?
In fact, I cant see a single reason why you would ever need or want to use Fahrenheit. The only temperature conversion you really need is celsius <-> kelvin, and thats just easy.

Because he's American and our intuitive notions of what temperatures feel like are in Fahrenheit.

 

[peter grimes]

In fact, I cant see a single reason why you would ever need or want to use Fahrenheit.

If you happen to be in the United States, you'll find that conversion estimate pretty handy.

 

[GoodGame]

On the subject of estimations, what does pi * 10^7 s approximate?

I'd guess 10 is for the acceleration of gravity again, except I can't figure why you'd want g to the 7th power.

I'll guess it has something to do with centripetal acceleration of a sattelite.

 

[dutchfire]

Hint: Note the unit (s = seconds)

 

[Mise]

3.14*10^7 seconds is how long it takes light to travel one light year?

 

[dutchfire]

Quite!

The actual amount of seconds in a year is 31.556.926 (according to google), so 31.400.000 is quite a decent estimate. I believe it's mostly used in astronomy. It's especially handy in Kepler's 3rd law (P/ 2 pi)^2 = ... if you have the period in years.

 

[ainwood]

3.14*10^7 seconds is how long it takes light to travel one light year?

So isn't that just "the number of seconds in a year"?

 

[Mise]

Yeah

Is it possible to light a lightbulb with an AA battery and one wire?

 

[ainwood]

Yeah

Is it possible to light a lightbulb with an AA battery and one wire?

Yes. Stick one pole of the light-bulb on the battery, and use the wire to connect the other pole to the other end of the battery.

 

[Mise]

God dammit that took me ages to figure out...

Your go!

 

[ainwood]

Ok: What is the Ranque-Hilsch effect?

 

[Perfection]

Some thermodynamics thing

 

[ainwood]

Its been 48 hours....


It is an effect seen in a vortex tube in which a fluid spinning at a high rate separates into two streams: A hot stream and a cold stream. There are some youtube videos on it if you search.


Open floor.

 

[Simple Simon]

good one, ainwood - had us stumpd there

OK, when I marinade chicken, I often use a mixture of salt, lemon juice, pepper, brown sugar and olive oil. I pour the juice into a bowl, add the salt - and the fluid bubbles and fizzes for a while. WHY (explain the chemical reaction)?

 

[Mise]

I have absolutely no idea what gas would be given off or why a gas would be given off at all! o_O Only thing I can think of is CO2 from the citric acid, but that would require something stronger than salt, surely?

 

[Simple Simon]

I have absolutely no idea what gas would be given off or why a gas would be given off at all! o_O Only thing I can think of is CO2 from the citric acid, but that would require something stronger than salt, surely?

Indeed, there should not be any gas...... so why is there? Remember that this is not happening in a chemistry lab, but in my kitchen.

 

[SS-18 ICBM]

I can think of nucleation, since pouring lemon juice makes it frothy, and then the air bubbles probably collect around the salt crystals.

 

[Simple Simon]

I can think of nucleation, since pouring lemon juice makes it frothy, and then the air bubbles probably collect around the salt crystals.

Nope, it it much simpler than that.

Imagine the scene: me in my kitchen, spooning salt from a glass jar into a bowl with lemon juice. What chemical reaction with these ingredients(!) can cause gas to be formed?

 

[Brighteye]

You're using too much salt. That's going to taste horrible, surely?

 

[peter grimes]

Question for the Questioner:

Does it matter if the lemon juice is squeezed fresh from a lemon or not?