Claire wrote to ask: Why does ice have a greater volume than water when we know that
kinetic energy increases as temperature increases. So, hot water has
a greater kinetic energy than cold water and therefore a greater
volume than water. Mass remains the same.
Without further ado, lets turn this over to my genius assistant, Triga:
Water is one of the most peculiar, and most studied substances on the planet. It is strange that ice has a lower density than it's liquid counterpart, but this has to do with the complex nature with which it forms bonds when reaching ~4*C. It is all governed by the two hydroxyl type groups (OH) which cause polar interactions between molecules (these are interactions between the slightly positive Hydrogen atoms, and the moderately negative Oxygen atoms). As you drop the temperature of water towards >~4*C, the molecules become packed together, but do not bond. Because of the V shape of the atom, and lack of bonding, the molecules can get quite close together, and even slide over each other freely. The kinetic energy of water disallows bonds to form, and therefore Ice is not produced.
Once enough kinetic energy has been removed from the system (ie the whole patch of water, or the portion first to freeze) the molecules line up for a long enough time for hydrogen bonds to form between the hydrogen (which is slightly positive) and a "lone pair of electrons" of the oxygen (an unbonded pair of electrons, which happen to be pushed further out from the nucleus because the hydrogen has donated a portion of it's electron "cloud" - electrons can never be said to be in one place, so a cloud is invisaged.) At different temperatures these hydrogen bonds have a descrete length, longer and longer as temperatures rise, until they are unviable to form. At between 0*C and ~4*C there are enough of these bonds to start ordering the structure, but not enough atoms with the right energy to form a solid. Therefore the liquid starts to expand a little (due to less flexibility of the atom arrangement as a whole). Once the temperature drops enough (<0*C) enough bonds form so that a solid forms. Because the angle between the two hydrogen atoms is a little less than 120*, it effectively plays havoc with the way you can arrange the molecules, and large gaps appear in the crystiline structure. This causes standard water to become much lighter (~1-5%) enough for ice to float. The kintetic energy is still lower than that of liquid water, so no laws have been broken, it is simply that the arrangement of moleculews that has caused an expansion. At very low temperatures, these bonds will become short enough so that water again will sink.
There are a few other chemicals which perform a similar crucifiction of logic, by having solids which will float on their respective liquids, most via a similar method: Lead, Uranium, neon and silicone are all examples of this phenomenon. Moreover, not all ice will float on water. Amorphous ice (ice which has been compressed, or very rapidly cooled) does not have the very ordered lattice structure which ice normally contains. Therefore, there is less space between the molecules, and a higher density.
Triga
Mike wrote to ask: What was the 12 amendment to the constitution?
The twelfth amendment to the United States Constitution sets out the procedure to chose the President and Vice-President. In fact, it did not create the Electoral College - it simply changes the way they voted.
Originally each elector cast two votes for President. The runner-up in the election became Vice-President. After a few elections, it finally occurred to someone that this was probably a poor idea, since it led to a competitor for the presidency becoming the Vice-President. Not only did this set up difficulties when former rivals with political differences were forced to work together, it was also thought that this set up a perfect situation for a coup'd'etat - considering that the Vice-President, in the case of the death of the President, would become President.
In 1804 the 12th Amendment was ratified, creating our current system where the electors cast one vote for President, and one vote for Vice-President. Should no candidate have a majority of the votes, the House of Representatives, voting by state, will chose the President. The Senate would choose the Vice-President.
And I bet you thought your vote counted.
You can read the complete text of the Amendment here.
Summer Fey Foovay
