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 Biggest Part: the Cerebrum. The biggest part of the brain is the cerebrum. The cerebrum makes up 85% of the brain's weight, and it's easy to see why. The cerebrum is the thinking part of the brain and it controls your voluntary muscles â the ones that move when you want them to. So you can't dance â or kick a soccer ball â without your cerebrum.