Guys
Can someone please answer something that has been bothering me for years. I know it sounds really daft, so I'm hoping that this was a wind up. Perhaps someone can enlighten me.
Many many years ago, before mobile phones became popular, I worked for a company that manufactured radio pagers. One of the engineers was explaining to me how they worked. He said that microwaves transmitted the signal. I asked if that was the same microwaves that powered ovens. He said that they were very similar.
I asked if that meant that mobile phones and pagers could heat up the earth - he said it was possibly but you would need millions and millions of them to do so.....
How many mobile phones do we now have in the world?
Please tell me it was a wind up and that we are not slowly microwaving our planet.
Mobile phones and microwaves
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Muddypause
- A selfsufficientish Regular
- Posts: 1905
- Joined: Mon Apr 11, 2005 4:45 pm
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I think what is being suggested here is that when a microwave hits some substances it can excite the molecules, make them more active, and consequently raise the temperature of that substance. Under certain conditions (like a microwave oven), the substance can be made to cook.
But actually, pretty well every way that we expend energy will result in something getting hotter. For example, we can expend energy making noise. If the resulting sound wave should hit a wall (or your eardrum, or just some more air) which absorbs the energy of the wave, the wall will heat up a little bit. The amount of energy involved is small, so the temperature rise is also small (probably unmeasurably small, actually). The same is true of light - shine a light at a wall, and the wall will absorbe some of the energy of the light, and consequently get a little warmer. I can even remember an A-Level physics question which asked, if you drop a block of ice from a certain height, how much of the ice would melt when it hit the ground - the point being that when something hits something else, some of the energy involved will become heat. A microwave will be bound by the same laws of nature, and the amount of 'heating' that it can do when it is absorbed by something will be dependent upon the amount of energy in the wave.
Almost every form of energy that we use is ultimately turned into heat. If we use a mobile phone we are expending energy, so something somewhere is getting warmer, but I don't think there is an issue of the substance of the earth being cooked as if it were in a microwave oven. Microwave transmissions are just one of many ways that we are using energy and converting it into heat, but I suspect the transmissions of (for example) several thousand digital TV channels being beamed around the globe are responsible for much more energy usage. And our use of cars is massively more significant - but even this is pretty small compared to the amount of energy we absorb from the sun. The real issue is whether we can lose that heat by radiating it back out to space, or whether it becomes trapped by greenhouse gasses.
But actually, pretty well every way that we expend energy will result in something getting hotter. For example, we can expend energy making noise. If the resulting sound wave should hit a wall (or your eardrum, or just some more air) which absorbs the energy of the wave, the wall will heat up a little bit. The amount of energy involved is small, so the temperature rise is also small (probably unmeasurably small, actually). The same is true of light - shine a light at a wall, and the wall will absorbe some of the energy of the light, and consequently get a little warmer. I can even remember an A-Level physics question which asked, if you drop a block of ice from a certain height, how much of the ice would melt when it hit the ground - the point being that when something hits something else, some of the energy involved will become heat. A microwave will be bound by the same laws of nature, and the amount of 'heating' that it can do when it is absorbed by something will be dependent upon the amount of energy in the wave.
Almost every form of energy that we use is ultimately turned into heat. If we use a mobile phone we are expending energy, so something somewhere is getting warmer, but I don't think there is an issue of the substance of the earth being cooked as if it were in a microwave oven. Microwave transmissions are just one of many ways that we are using energy and converting it into heat, but I suspect the transmissions of (for example) several thousand digital TV channels being beamed around the globe are responsible for much more energy usage. And our use of cars is massively more significant - but even this is pretty small compared to the amount of energy we absorb from the sun. The real issue is whether we can lose that heat by radiating it back out to space, or whether it becomes trapped by greenhouse gasses.
Stew
Ignorance is essential
Ignorance is essential