Which of the following represents a chemical change? A. Melting
of ice to water.
B. Combustion of a firecracker
C. Salt dissolves in water
D. The iron stretched into wires-ductile and iron pounded into sheets-malleable.

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.