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.
If we only used 10 percent of our brains, that would mean that weâre all effectively evolving in the opposite directionâand very quickly. Another obvious way we know that we use more than 10 percent of our brain is through functional magnetic resonance imaging and positron emission tomography. fMRI and PET are imaging techniques that reveal areas of relatively high brain activity in real time.