For example, the brown crust on atoaste d marshmallow is the result of sugar changing to iffer-ent substances in a mixture called caramel. A change in matterthat produces one or more new substances is a chemicalchange, or chemical reaction. The burning of gasoline in acarâs engine is a chemical change.
How much brain power does the average person use? About only 10% Though an alluring idea, the 10 percent myth is so wrong it is almost laughable, says neurologist Barry Gordon at Johns Hopkins School of Medicine in Baltimorâ¦e.
Researchers have used MRI and PET scans of the human brain to show that far more than 10 percent of the organ is used even at rest. In fact, studies suggest that during any given day, fully 100 percent of the brainâs area is active.