days ago, to mark the entry into force of the Kyoto Protocol, we could see in the news as pointing to a few years, rising sea levels as a result of the "global warming" would affect English coast (the English coasts are affected by other problems, not only due to global warming, but from the point of view of the media seems not to matter too much).
that made me remember an old home physics experiment.
Melting "ice caps"
vessel
The simple experiment is entertaining and very educational. Illustrates much about the nature of water also is achievable by anyone (regardless of race, sex and religion, as they are fashionable constitutions and rights issues, lol, take the opportunity to speak).
Let us take a bottle, if it can be graded best (if not, nothing happens) and llenémoslo with a certain amount of water. If the bottle is graduated, look at the height of the Let us note the water column and on paper. If not, make a mark on the bottle.
Once done, let's get a certain amount of water in the bottle (not all) and congelémosla. The remaining water was preserved in the same bottle.
Like cooking programs, we'll skip the step of describing the wait for water to freeze, because in that way is a lot of freedom: each one can be entertained as you like waiting for water to cool.
Once the water is frozen, gather them and throw ice cubes into the bottle, and note how far the water level.
In this experiment, we see that the water level in the glass when we only have water never exceeds the water level of the two water-ice system (For the same mass, of course).
Why does this happen? As we know from childhood: the liquid water is denser than the solid, ice. This implies that for the same body of water, ice take up more than water. This is related to the crystalline structure of ice (ice would be more accurate to say I, which is the ice crystal structure in nature, but they know more ways in which ice can crystallize) is such that the spacing between water molecules are greater than when liquid.
Once the experiment, we heat the ice and see how easy (in terms of time and energy) that is melting the ice and leads us and costs the water cool and freeze, but that's another story we do not care now.
vessel to Earth. The melting of Arctic
The Arctic Circle, the circle limited by geographic Siberia, Greenland and Canada, is a huge block of ice floating on water. As defined for days on "The Edge of the impossible" physical geographer Eduardo Martinez de Pison, is a "Mediterranean ice." A great way to describe it because, unlike the Antarctic (where we have a landmass covered with ice) is a real sea, instead of water is ice. A large cube floating in a glass.
Now we can realize the implications of it, just seemingly innocent home physics experiment that we see above. The melting of the Arctic, in principle, has no implications for sea level rise, in any case, would imply a decline, as the water would occupy less volume.
What really matters, from the perspective of sea level rise is the melting of large ice sheets of Antarctica and glaciers, now in a recession, associated with large mountain ranges (Andes, Alps, Himalaya , ...). These are what have implications for sea level, it does not forget that represent 1.5% of Earth's water (not enough, but exclude seawater, which is 97%, we began to realize what actually represent in terms of quantity, because the river water is 0.0001 and the atmospheric water vapor, the 0.001).
Another thing to discuss is the following fact: the bodies expand when heated. And water is no exception. Although the thermal expansion for water is not very clear, given the enormous amount of water in the oceans, a rise in temperature a few degrees centigrade means a rise of sea water level of many centimeters.
Finally I would stress something else: that the Arctic thawing is irrelevant, it means that I get according to their melting. Whoever does not have implications for sea level, does not mean you have other problems: the melting of the Arctic is a huge input of freshwater to the sea, which represents major changes in their physical parameters, such as salinity, temperature, point freezing ... This has important implications for the environment, weather, and may even, in ocean currents.
In this regard, a geologist paleoclimatologist of Columbia University noted that, paradoxically, a thaw important in the Arctic caused by an increase in temperature was responsible for an episode of sudden, intense glaciation, known as "Younger Dryas" años.Pero 12,000 years as the narrator said at the end of Conan: "That's another history. "
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