Ok, first question. This might be stupid, but what keeps atoms bonded to other atoms?
This is really more of a chemistry question, but the simple answer is that atoms are most stable when the have a full outer shell of electrons, either through covalent or ionic bonding. In the case of ionic compounds (salts) the opposite charges bind the atoms in crystals
As in if two pieces of wood from the same tree are set next to eachother, why dont they bond? I know its a stupid qeuestoin, but what is stopping them from doing so?
Also a chemistry question. The answer is electron repulsion, the same force responsible for almost every interaction you experience on a daily basis and the reason you don't fall through the floor even though you and it are both made up of almost entirely empty space. The electrons of the atoms repel one another.
Atoms in wood are already bonded, primarily as a long chain of sugars known as cellulose. These bonds can be broken, (by combustion for instance) but won't do so instantaneously without something to drive the reaction.
What do color and taste have to do with physics?
Color? Lots. The color we perceive is due to the frequencies of light being absorbed, reflected and transmitted by the object. While this is an oversimplification, if something is green, it is because the object absorbs most frequencies, but reflects green. Something white reflects almost all frequencies of light and something black absorbs almost all frequencies, which is why black is a bad color to wear on a hot day.
Taste? Doesn't have much to do with physics, as it is more of a biology and chemistry topic. I can give you a long answer if you like, but basically the different receptors on your tongue send information to your brain based on the molecular makeup of the food you are eating, in some ways similar to your sense of smell.
Why do two different sources of water taste different? If they are made of the same thigns molecularly, shouldn't they taste the asame?
As already noted, pure water does taste the same. Or to be more accurate, pure water is said to have no taste at all. Most of us live in cities where there are impurities in the water, either unintentionally or purposefully, like in the case of flouride compounds added to many water supplies for its dental health benefits.
Some places (like Pilsen in the Czech Republic) have really soft water, but most of us either get impure tap water or buy bottled water, which is either comes from natural sources of pure water (Evian comes from Lake Geneva after being filtered through glacial sands) or is produced by sending city water through reverse osmosis. Dasani water is filtered this way.
And how are things clear? And how can two different plastics be two different colors if they are the same at the atomic level?
Things are clear if the spectrum of visible light is neither reflected or absorbed by the material but rather it passes through. We are able to see that they are there because (1) a small percentage of light is reflected, which is why we can see a faint reflection of ourselves as we look through a window and (2) light travels at different speeds through different materials, which is why a straw looks "bent" when it sits in a glass of water.
Plastics are different colors either because a dye is used or they aren't the same at the molecular level. Plastics is a very general term that is applied to a great number of man made polymers.
