What is the difference between low density and high density?

Most of the volume of an atom is occupied by the

Scientists follow specific processes in order to determine valid explanations and conclusions from observations. david observed strange lights in the sky above his home outside of roswell, new mexico. the only explanation that makes sense to him is that there are ufos in the area. what should david do next to verify his explanation?

Which of the following are forms of phase changes a. freezing b. condensation c. heating d. exchanging