One of the rescue workers has a special flashlight; it has a crank, and the light shines when the crank is turned. Since the rescue worker has never had to replace the batteries or plug in the flashlight, she thinks this flashlight works without an energy source.
How could you convince her that the flashlight cannot work without an energy source?

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).

the rocks are classified by the geological process they are formed by. the three main groups of rocks are igneous, metamorphic, and sedimentary. minerals are not they are classified under the chemical classes they are in. these groups include silicates, sulfates and carbonates.