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.
The humans brain makes up what percentage of the total weight of the human body? In a person weighing 150 pounds, the weight of the brain makes up  approximately two percent of the person's weight. The average brain  weighs between 1,300 and 1,400 grams â¦in an adult and 300 to 400  grams in a newborn.