1. The Panel

Comment #53761 by Krister Bratland on July 3, 2007 at 3:52 am

You are right, I got them backwards. 60Hz is for the US. My apologies.

2. The Panel

Comment #53714 by Krister Bratland on July 2, 2007 at 7:59 pm

19. Comment #53702 by Rtambree on July 2, 2007 at 5:57 pm

"It's the charge that moves, not the electrons. Electrons' A to B drift velocity is far slower than walking pace."

I beg to differ. A particles charge is intrinsic, and same charge particles repel eachother. Rather than exchange their charge, they transport the charge by moving through the conductor.

"An ordered motion of charged particles in a particular direction (in metals, these are the electrons) is known as electric current."

http://en.wikipedia.org/wiki/Electric_charge

"When a metal wire is connected across the two terminals of a DC voltage source such as a battery, the source places an electric field across the conductor. The moment contact is made, the free electrons of the conductor are forced to drift toward the positive terminal under the influence of this field. The free electron is therefore the current carrier in a typical solid conductor."

http://en.wikipedia.org/wiki/Electric_current

On your other comment, I agree that the questions revolve around fairly basic issues, but we all know how easy it is to forget knowledge we acquired in school if it is not being applied for a sufficiently long period. Why should it be different for a scientist?

Krister

3. The Panel

Comment #53695 by Krister Bratland on July 2, 2007 at 4:49 pm

15. Comment #53588 by stephenray on July 2, 2007 at 6:13 am

"I'm glad someone else pointed out about UK mains current being AC; no electrons get back to the power station, do they? They don't move far enough. What's the frequency of mains electricity?"

In an AC current, the electrons move like links in a chainsaw, back and forth, induced by a rotating magnet and wire coil. The electrons jump from atom to atom in the cable, but never get lost to the circuit, and they are not stored in the power plant.

What happens in the light bulb is a kind of friction caused by the resistance in the coil inside the bulb, leading to an energy build up at that point in the circuit. This energy is released in the form of packets (quantas) of light that we know as photons, but the electrons never leave the cirquit themselves.

The frequency of mains in the UK is around 60Hz. This is due to the frequency of revolutions in the magnet/coil which is inducing the current.

Regarding the questions posed in the article, one of them illustrates how seriously it should be taken:

"Q: Is a clone the same as a twin?
Answer: Yes, up to a point (see Robert Winston's answer)."

If you go beyond that point, the answer will be "no". This means that the correct answer is "yes and no", and so all the answers are correct. The question leads nowhere.

Regarding the fact that scientists are unable to answer some of these questions, I don't hold it against them at all. I defy anyone to know everything. It is not practical for one person to build up expert skills in all areas of knowledge. This is why we have specialists and experts on different subjects. A cosmologist does not strictly need to know photosynthesis, and if he/she comes accross a scenario where it needs to be understood in their line of work, they can look it up or ask the experts.

The strength to admit that you don't know is a higher virtue than the will to give the wrong answer.

Krister

4. Nato accuses Taliban of using children in suicide missions

Comment #53338 by Krister Bratland on June 30, 2007 at 9:24 pm

Sadly, we can not expect this to be the last of its kind.

5. The Stupidity of Fox News is Truly Beyond Belief

Comment #52853 by Krister Bratland on June 28, 2007 at 8:38 am

Hearing a priest talk about good and bad science is like trying to dig a hole in water - it just doesn't work...

Krister

6. Teaching assistant quit in protest at Harry Potter

Comment #49198 by Krister Bratland on June 11, 2007 at 1:28 am

Mr scottbly

This is not Mr G. Teapot's logic, he is being sarcastic. If people took up broomstick flying instead of driving their cars, pollution would probably be history.

What remains to be seen now is wether I can make my broomstick fly if I only pretend hard enough, I'll report back later with my progress.

Krister

7. Manliness is next to godliness

Comment #49147 by Krister Bratland on June 10, 2007 at 3:50 pm

Stine's wife, Desiree, says she supports manly leadership; it seems to her the natural and God-ordained order of things.

8. Teaching assistant quit in protest at Harry Potter

Comment #49096 by Krister Bratland on June 10, 2007 at 9:38 am

Only a religious person could take a work of fiction that seriously...


Krister

9. Man to die over insult

Comment #47109 by Krister Bratland on June 3, 2007 at 3:19 am

Re: 9. Comment #47057 by jaytee_555 on June 3, 2007 at 12:10 am

Does anyone know if there is a petition we can sign, or the address of some Pakistani official we can write to try to help this unfortunate man?