[12markkram34]

I do not understand exactly what a quantum is or what Planck's Constant is. My textbook (Addison-Wesley) says that a quantum is the amount of energy required for an electron to jump to the next higher energy level. However, it says that Planck's Constant times frequency is a quantum. If this is true, wouldn't the quantum change if frequency changed? The book also talks about the "size of quantums," which makes no sense at all. I have tried reading Wikipedia, everything there doesn't make sense either. How does Planck's Constant relate to the quantum anyways?

Can someone please help  ?

[Borek]

a quantum is the amount of energy required for an electron to jump to the next higher energy level.

Correct.

However, it says that Planck's Constant times frequency is a quantum.

Correct.

If this is true, wouldn't the quantum change if frequency changed?

For a given system these frequencies are constant - they won't change. Different systems have different energy levels (different frequencies observable).

The book also talks about the "size of quantums," which makes no sense at all.

This is just an amount of energy of the quant.

Note, that while Planck's constant is used to express quants of energy, they don't have to be integer multiples of the h - quite the opposite.

[12markkram34]

I am still not understanding it. However, I now have a more important question.

According to my textbook:

"Bohr answered in a novel way the question of what prevents electrons from falling into the nucleus. He proposed that the electrons in a particular path have a fixed energy. Thus they do not lose energy and fall into the nucleus."

After reading this over and over, I have come to the conclusion that Bohr did not answer the question at all! He didn't explain (even the slightest bit) why the electrons do not lose energy. Basically all he said was "They don't...because they don't." Does anyone really understand why this happens? Like gravity. "Gravity is caused by gravitons." What are gravitons? Why do they attract us? Is it even possible to understand science at all?

Sorry if this is a rant, but I really want to know.