If the lights are off in a room and there are no windows, why do most objects appear black?

Asystematic approach to problem solving is called a (an)

How do you know how many valence electrons an atom has?

Ateacher gives students four liquids commonly found in the kitchen - vinegar, apple juice, dish detergent, and milk - and ph indicator strips, which measure acidity. the teacher asks the students to put the liquids in order from most acidic to most basic. what type of investigation could the students conduct to determine the correct order for the liquids?