They would only know the width of the window. A floor plan is like a top down view of a building. Imagine that you cut your house in half horizontally, and then looked down at it. All you would see would be the width of the windows, not the height or anything else.
You may confuse two minerals by their colors so using streak is another way for showing their "true colors "
Answer:
Atomic mass is defined as the number of protons and neutrons in an atom, where each proton and neutron has a mass of approximately 1 amu (1.0073 and 1.0087, respectively). The electrons within an atom are so miniscule compared to protons and neutrons that their mass is negligible.
I hope this is the answer you were looking for :D