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.
Mac Evolution. 13 February 1998. It's well known that the human brain accounts for about 20% of the total oxygen consumption when a person is at rest, so let us assume that the brain accounts for 20% of the total body energy consumption.. 20 W.