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Have you ever tried to clean a greasy tupperware with just water? It probably didn't go all too well. This is again down to the polarity of molecules. Grease, and other types of oils are non-polar molecules, which don't have the necessary split in charge required by water molecules (polar) to break them apart, and thus dissolve them.

However, add some soap and the grease comes right off. So the logical conclusion to reach might be that soap is made up of non-polar molecules, but this too isn't strictly true.

Soap, like fats, is a hydrocarbon chain. i.e. a large chain consisting of interlinking carbons and hydrogens. The difference between most fats and soap is that soap molecules have two different ends. One end of the soap molecule is a saturated hydrocarbon end, i.e. it is non-polar. Whilst the other end the polar, i.e. hydrophilic. Thus when you have something that is non-polar the non-polar end of the soap molecule interacts with that allowing it to be dissolved, whilst polar substances interact with the hydrophilic portion of the molecule.

Quite the versatile substance I would have to say.

If you've ever had a chilli before you're probably quite familiar with the not entirely pleasant feeling of having your tongue lit on fire. On more than one occasion, having been a bit too flamboyant with tabasco bottle I almost thought I could breath fire.

Now you're mom, or someone else, will probably have told you to drink milk. Water doesn't help they say, and I have no doubt you've experience it for yourself. There's actually a very logical chemical explanation behind this.

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Now substances can be classified as one of two things. Either polar, or non-polar. This essentially states whether or not there is a greater electron density in one area of the molecule versus another. To determine whether or not a molecule is polar you first look at the bonds. If two substituent atoms are different molecules, they will have a polar bond. The amount of polarization will depend on their respective electronegativities (the pull of a nucleus on a shared pair of electrons), the greater the difference in electronegativtiy the more polar the bond. But just having polar bonds doesn't necessarily mean that a molecule is polar, to determine this you need to look at the symmetry of the molecule. If it is symmetrical, i.e. the shape of it as well as the substituent atoms attached, the molecule is said to be polar. If this isn't the case, it is a non-polar molecule.

Now when such substances are dissolved in solution, there is a helpful phrase that helps characterize their properties: "like dissolves like". In other words, a polar molecule will be dissolved by a polar solvent, and a non-polar molecule will be dissolved in a non-polar solvent.

Capsaicin, the molecule largely responsible for "spicyness" is a non-polar molecule. Water, on the other hand, with highly polarized bonds and two lone pairs (making it non-symmetrical), is highly polar. Thus drinking water doesn't really do much. In contrast, milk contains some amounts of fat, i.e. triglycerides, which are long chains of saturated hydrocarbons. These fat molecules are non-polar, allowing the capsaicin to dissolve into the milk and thus is removed from the mouth. And voila, your mouth no longer feels like a dragon breathed into it.

By the way, ice cream does the same trick.

If you've taken a basic chemistry course you've probably been taught about electrons. In case you haven't, this is the gist of what you need to know.

Now every atom is made up of what is called a nucleus. In the nucleus you have two subatomic particles (not actually the smallest thing, they are made up of more fundamental molecules called quarks, but I won't get into them just yet), namely, protons and neutrons. There is one notable exception in hydrogen, which only has one proton in its nucleus, though its heavier derivatives, deuterium and titrium have one and two neutrons respectively. But I digress, protons are positively charged particles with a relative mass of 1, whilst neutrons and neutral (creative names I know); neutrons are also assigned a relative mass of 1 (atomic mass units). Now orbiting around this nucleus are electrons, which are negatively charged particles, with such as small mass as to be negligible. Now depending on where you are in your chemistry education you will have been taught different things about them.

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It's unlikely in this day and age that you've been taught the "plum pudding" model of the atom, as this was one of the earliest renditions, and other then getting the charges right, is pretty much wrong. What you were probably taught was the Bohr model of the atom. This states the electrons orbit the nucleus in concentric circles, like the planets the sun. There's really no eloquent way of putting this, but this is also wrong.

Just thinking of the behaviour of an electron, this is just a really unlikely circumstance. Electrons quite literally defy the laws of physics, and a new branch of it (quantum physics) had to be developed to explain these oddities (again I'll spare you the detail for now). Thus, knowing this what are the odds that electrons would be content orbiting a nucleus in quaint little circles? Quite unlikely.

Instead they are found in orbits. The shape and type of orbit depends on four different, unique, quantum numbers assigned to each electron, which I also won't get into. The nature of these orbitals can be determined using a very complicated equation derived by Schrodinger. The lowest energy orbital is essentially a sphere, followed by a larger sphere, which are then proceeded by more and more complicated shapes, some of which have yet to be derived. All I want you to know is that the area that the shape covers is said to be the area that particular electron occupies. But this shape is given by a probability density function, i.e. the resulting value is a probability. I can't quit recall the exact number, and it also depends on which orbital is being talked about, but suffice it to say it's less than 1. In other words, the probability of an electron being in that orbital is quite high, however, and here's where the crazy part comes in, if the electron is not in that orbital it can quite literally be anywhere else. It could, for example, be on the Great Wall of China, now the probability of this is very low, but it is not impossible.

Kind of neat to think some of your electrons might be whizzing around Antarctica right now.