scientists have really observed atms & sub-atomic particles?

Answer 1

i have actually had the opportunity to observe them myself. quite a magnificent sight, i must say.

Answer 2

Wow, an intelligent question instead of a "please do my homework for me" question. The answer is yes, but perhaps not in the way you think. The things we see interact with visible light, the shortest of which is 400 nanometers long. To give you an idea of how big that is, it's vaguely a tenth smaller than any cell in your body. Yet, that's still >1000 bigger than even the biggest atom, and so you can never "see" atoms in the conventional sense, that is using visible light. You can think about it like this: light can be thought of as waves, and for it to "see" something it has to be vaguely in the same size. For example, if a wave on a beach is 6 feet tall, will it "see" (that is interact) with a speck of dust floating on the water? Not really. But if you're ~6 feet tall and standing in it's way, it will sure "see" you--i.e. interact with you by knocking you flat on your face.

So if you want to "see" atoms you have basically two options.

Option #1: Use wavelengths that are small enough to see atoms and molecules. Light in that size-range is in the x-ray part of the spectrum, and people have used various techniques using x-rays to "visualize" atoms and molecules. If you see a "crystal structure" talked about anywhere, for example, it was visualized using x-rays.

Option #2: Don't visualize it directly, but infer the atoms. Much of this is done using techniques such as scanning microscopy. The way scanning microscopy works is that you have a very very very fine tip, literally one atom thick at its point. And then using very precisely calibrated machines, you run that tip very slowly over something. If the tip runs "into" something then their electrons will repel and cause the tip to move up (or generate current, etc. depending on the specific technique used). After slowly running the tip over the entire sample, you get a very detailed (i.e. atomic level) picture of the what you were looking at. To imagine something like that in real life, imagine having a fruit basket, running your finger across it while blindfolded, and trying to imagine everything in the fruit basket based on that.

There are other techniques people use, but most of them generally fall into one of those two types of approaches.

Subatomic particles can never be directly visualized. First, the wavelengths that would interact with same are FAR too energetic, so you could never work with radiation of that wavelength. Second, since the smallest "tip" you can have in a microscopy type of technique is an atom, you cannot use that type of approach to visualize something smaller than an atom (and even the easy subatomic particles, such as protons, neutrons, and electrons, are millions of times smaller than whole atoms). However, since most subatomic particles are extremely energetic, they interact with matter in predictable ways. The classic way that they were indirectly visualized was with cloud chambers--atoms would be smashed together in gas, and when they would essentially explode you'd see lines and curves of bubbles forming in the gas in ways that could be mathematically predicted based on the knowledge of the particles. Many subatomic particles were also discovered in such ways, because people saw lines and curves in the bubble chambers that they couldn't explain, so they realized a new particle must exist.

Sorry for the long-winded answer, but I hope it actually helped.

Answer 3

The Heisenberg Uncertainty Principle: you can know the position, but not the velocity of a particle. You can know the velocity but not the position. The act of observation changes the observation.

Answer 4

In a way they have, but in a way they have not. They have developed ways to see them, but the way to see is not a very accurate way to see. Its like trying to see a grain of sand when your eyes are the size of jupiter.

Answer 5

Yes.

Answer 6

No, they can prove their existance but they can't see them as they are too small.