What causes the sudden change in volume when I touch the aerial of my stereo?

- Liam

New Zealand

I live in Russia and we have a real full-sized Russian Winter this year. This means the central heating doesn't cope and you have to use electric heaters in addition to get your rooms warm.

As far as I understand, when you fail to save energy, it is lost as heat. So does it make sense to use energy-saving lamps instead of bulbs, turn off computers when they are not needed, and so on, when in the morning I turn on a heater and wait till the office gets warm. Maybe if I used a lot of energy-wasting stuff (taking the kettle and the toaster from the kitchen into my office, of course) I could turn the heater off earlier and the result in warmth as well as in needed electricity would be just the same?

  Oh, and can there be any "more" or "less" effective electric heaters if all "lost" energy turns into heat anyway?

Does anybody know what the electronic component shown in the pictures might do?

It was part of a 1930s collection given to me by John Harwood, a watchmaker from Dunster, Somerset, UK. Harwood inherited the collection from his father-in-law, Herbert Stacey, who was an electrical technician.

Joop van Montfoort, By email, no address supplied

If all road vehicles were electric, I'd like to know how much electrical power would be consumed ( and how many more power stations would be needed ) to keep things running at more or less the same levels of traffic as today. . .

What impact can this have on how they work or on the circuitry inside the remote control itself?

These particular batteries have been in use for more than 12 months, so they may well be nearing the end of their useful lives.

Nia and Steven Faulder, by email, no address supplied

In common parlance, one would say the body 'burns' food, and, indeed, we are warm creatures due to some kind of exothermic reaction(s) inside us, yet our muscles and brain work on electrical impulse. Is this the most efficient conversion of heat to useful energy we know of, or is the electrical energy converted from chemical potential energy somewhere?

Lke the existence of chemical source of Direct Current, do we have chemical sources of Alternating Current? If there are such systems, what will be their unique applications? We have Oscillating chemical reactions which deal with varying factors. Similarly is it possible to have chemical source of Alternating current?

On a number of brush metal laptops/appliances if you run your finger lightly across the surface it creates a vibration sensation in your fingertip; this is not friction it is an actual vibration, I can categorically say that it is caused by some kind of electrical interaction is that the sensation only happens when your appliance is plugged into the AC power which suggest it is something to do with the frequency of AC power, but my question relates to the actual interaction between the metal surface and my finger, what is causing the feeling?