- How is it possible that electrons act differently when we observe them? The matters such as the double-slit experiment and Heisenberg’s uncertainty principle shows us that matter is far removed from the known physical reality. Can you elaborate on this?

- I think one of the things that makes it hard to think about electrons and atoms is that they are at such tiny scales, we are always thinking by analogyof something like something else that we have in our normal experience. And we normally think of little billiard balls, little balls flying through space, that’s often times we think of the electrons and so on. But actually in the last 100 years, the way that we think about microscopic quantum mechanics probably gives another analogy a lot better footing, which is to think of it as a really something more like wave in the air. So right now I’m talking to you through the air and there are sound waves coming at you and if you know anything about music, you know in music, there are resonances. So if I’m playing an instrument, I get different notes at different points of frequency and those are what we call resonances. And so when we think about the electron around an atom and so on, in a lot of ways, what we know now from modern field theory is that we should sort of think of it fundamentally as more like a wave filling space. And then the particles, the electrons are things that sometimes are coming out from that wave picture that’s resonances, but not always. So in some ways, a lot of our institution about these things comes from thinking of little billiard balls flying around and asking where is that billiard ball at all different points and so on. Actually, that’s often times not the right question to ask. One of the things I think is a kind of an important aspect of modern physics that doesn't really get talked about a lot is that there two types of particles;two broad classes. One of them is what we call fermions and the other is bosons. Fermions are electrons, protons, all the sort of things you think going on in the atoms. And they have a special property that they cannot be doing the same thing at the same time. So you cannot have two electrons doing exactly the same thing. So one thing that leads to is that they push away from each other. So all of the solid things that we feel around us… that property comes from the fact that fermions are pushing away from each other. On the other hand things like light and sound are energy waves and those particles can pass through each other and they don't repel in the same way. So we normally think of photons and light as easily as a wave, where the waves pass through each other. And the electrons we think of as very solid, but quantum mechanics tells us that sometimes not so cleanly different from each other. Sometimes the electrons have wave properties and sometimes the photons have particle, the light has particle properties. So, I think in some ways, we can get into trouble when we try to think of the atomic things as sort of too much like a billiard ball, too much as our little object flying around, when in fact the wave picture is a much better picture a lot of times.