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.
1 The 10-watt number might be the source of the myth that humans use only 10 percent of their brains. 2  Actually, almost all parts of the human brain operate to some degree at all times. 3  The brain has more than 1,000 trillion synaptic connections. The 10-watt number might be the source of the myth that humans use only 10 percent of their brains. 2  Actually, almost all parts of the human brain operate to some degree at all times. 3  The brain has more than 1,000 trillion synaptic connections.