Science is both what you learn in science class and what you do in science class. It’s knowledge about space, energy, atoms and the human body. It’s also a method of investigation, which is the process used to build that knowledge.

Science is focused on and limited to the natural world, or things we can perceive directly with our senses or indirectly with tools. The effect of radiation on human cells is a topic scientists can study because they can observe and measure it. The effect of an imperceptible, supernatural force on human life is not a scientific topic because it cannot be observed or measured. Science must be testable. That means you can experiment and/or investigate a scientific claim or hypothesis.

Which of the following is not an example of a question for scientific study?

A
If ghosts are real, how do they move?

B
If a factory opens in a city, how will it affect air quality?

C
How does sunlight affect plant growth?

D
If a person starts exercising, how will their health change?