Is the ice at the poles because of?

Heat makes the frost on your window MELT.

The poles are frozen because they receive less heat energy from the sun. The sun, depending on the time of year is hitting head on somewhere between the tropic of cancer or tropic of capricorn. The poles always get less heat than the tropics because the earth is round, and the concentration of energy is on an angle.

Try it with a flash light. If you shine it straight down on the floor you get one really bright spot. Now shine the flashlight on an angle. The light is less bright and more dispersed. The tropics get this high concentration of straight-on heat from the sun. The poles get the dispersed light on an angle.

The earth's internal heat is not enough to melt ice on its surface. Again, the earth is round, and so the distance between the hot inner core and the cooler outer crust is more-or-less the same all over the planet. It would thus not make sense from one area to be frozen and another tropic if internal heat was capable of melting the poles.

Hello John,

I’m assuming that the icing o your windscreen only happens on cold days, if not then it sounds like there’s something wrong with your air-con and the coolant is leaking.

If the air coming out of your heater contains moisture then the moisture will freeze on contact with the cold windscreen, even if it’s warm air. The heat from the air will start to warm the glass, once the glass warms to in excess of 0°C you’ll start getting condensation as opposed to ice.

The volumetric heat capacity of glass is more than 1,000 times that of air (meaning that one cubic unit of glass contains about the same energy as 1000 units of air). On a cold day in particular, it means that a lot of warm air needs to impart some of it’s energy into the glass before it stops icing over.

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When the Earth first began coalescing it was a seething cauldron of highly radioactive molten rocks. The radioactive decay generated vast amounts of heat and pressure, this continued for the first 700 million years of Earths life, by which time the planet had cooled enough for solid rocks to form, the cooling continued until such time as liquid water collected on the surface.

Today there is still radioactive decay within the Earth and this produces heat energy that escapes to the surface, geothermal activity also releases heat in this manner. Throughout the year this heat loss is fairly constant around the planet and amounts to some 40 terawatts from radioactivity and another 47 terawatts of geothermal energy. Other heat sources contribute to Earth’s energy budget as well including internal tidal friction, radiation from space, solar winds, direct heating (fires, machinery etc) and even light from distant stars.

All of these are dwarfed by the energy from the Sun, this alone produces 99.97% of the energy within the Earth system. Given that all inputs generate 33°C of heating then the contribution from radioactive decay will be in the order of 0.004°C.

The reason for the ice being at the poles is aptly described by Now or Never and the torch analogy.

Earth’s position is space means that we receive some 1363W of solar energy per square metre on a plane perpendicular to the Earth’s surface at an altitude of 100km. Descending from this height we pass through the clouds and atmosphere, these block out about half the Sun’s energy. At any one time half the planet is in it’s own shadow and receiving no solar radiation, averaged across the whole year and across all of Earth then we receive approx 340W/m².

At any one time the Equatorial point directly beneath the Sun receives the maximum solar radiation, moving away from the Equator sees solar intensity decreasing, by the time the Arctic and Antarctic Circles are reached (67.6°N and 67.6°S) solar intensity is about 40% of that at the Equator, at the geographical poles it’s about 25%.

It’s the fact that the Polar regions receive less solar radiation than other parts of the planet that ensure they’re cold. On top of this is the fact that ice is reflective, most of the sunlight hitting the icecaps is reflected back into space (50% for dirty multiyear ice and up to 90% for freshly formed ice), contrast this to the oceans which only reflect 8% of sunlight.

No.

Cold is the lack of heat. Years ago scientists thought cold was a thing, like heat energy is.

The poles don't get as much heat as the rest of the earth. Because of the earth's tilt, the south pole gets less heat from the sun than anywhere else on the earth.