When a magnet lifts a metallic object against gravity, it is doing work and energy is being converted. Where does this energy come from? Presumably it comes from the magnet- but what form does it take and does it eventually get depleted- or - is the energy restored as the metallic object is pulled away from the magnet?

Thanks

Steve Fletcher

Simon Galloway

Andy Carter

Anaesthetic Dept

Bradford Teaching Hospitals

Is there way to use the pull/push of magnets to make some sort of motor and if so would it be true free Energy ?

The other day I was opening a letter at dusk without the room lights on.  As I pulled the seal apart, I thought I saw small flashes of bluish light at the as the strands of glue broke. Has anyone heard of energy being released in the form of light when glue bonds are broken?  Might there be some phospherent chemical in the glue which is activated when the material is stressed?

The concept of getting to orbit via a "Space Elevator" has been around for years and seems to be gaining ground.

Leaving aside the practical difficulties such as manufacturing a strong enough filament, what would be the advantage?

Surely the "lift" would not only have to haul itself and its payload up to say the geosynchronous altitude but would also have to provide sufficiant energy to bring itself to the orbital velocity. Given that achieving orbit would probably take days rather than the shuttles' minutes, complex life support systems and supplies, with redundant systems, would also be required. Then again, energy would have to be supplied to negate the orbital speed on the way down.

Where exactly would be the savings over conventional orbital transition? Am I missing something?

My wife and I recently decided we could not, in clear conscience, make a trip to London merely to attend a wedding.  We were both sure that the cost to the planet of such whimsical continent-hopping must be unsustainable, but had no real idea just much energy it takes to move one adult from Johannesburg to London by air (approx 9000kms or a quarter of the way around the world).  We'd love an answer expressed in everyday terms like say tumble-drier-hours, or 100W lightbulbs burning, etc.

Tim Greene Johannesburg

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?

I have a Laser Detector for my Rotating Building Site Level. In a room with an Energy Saving bulb, if I only turn the detector on , it ‘Beeps’, advising it has received a signal. This doesn’t happen in a room fitted with an old fashioned tungsten bulb. Does an Energy Saving bulb give off Laser Light?

I imagine a time where a fusion reactor starts off with hydrogen and makes heavier elements and produces energy. Next to that you could have a fission reactor that splits the waste from the fusion reactor to create hydrogen and energy.

Something doesnt add up to me are some fundamental laws of energy not violated here?