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.
    Answer   The average human brain weighs three pounds (1.36 kilograms). The average female brain capacity is 79.3 cubic inches, slightly smaller than the male â¦ brain of 88.5 cubic inches. The largest human brains may be twice those of average size, but size has no relevance to brain performance.he average size of a donkey's brain is comparable to a human. The  donkey's brain is between 50 and 75 percent of the size of the  human brain.