A(n) is a single explanation and is supported by lots of point
evidence over a long period of time.*

hypothesis

educated guess

theory

natural law

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

Consider a hydrogen atom in the ground state. what is the energy of its electron? =e= jj now consider an excited‑state hydrogen atom. what is the energy of the electron in the =5n=5 level? =e5= j

How much energy will be transferred to your eardrum while listening to this sound for 1.0 min?