What is meant by an "elementary particle"?

Describe the progression of ideas about what particles are truly "elementary".

What particles are currently considered to be the building blocks of all matter?

Describe the difference in protons and neutrons in terms of the quarks which make them up.

No one has seen an isolated quark. Why not?

Why are huge, high energy accelerators required to observe the tiniest of particles?

What has led to the close cooperation between those who study the very smallest things (quarks, leptons) and those who study the very largest things (galaxies, quasars)?

Which two of the four fundamental forces have now been shown to be "unified"?

What is meant by "grand unification theories (GUT)"?

What evidence do we have that all parts of the universe are expanding? How is this expansion related to the measurement of distance to remote parts of the universe?

What is the 3K background radiation? What is its significance to the modeling of the formation of the universe?

Why is the relative abundance of hydrogen and helium considered to be such an important part of the modeling of the universe?