Which of the following is a physical change

a copper roof changing colors from orange to green
sawing a piece of wood in half
rust forming on an iron fence
burning a piece of wood

Abullet found at a crime scene may be used as evidence in a trial if the percentage of metals match to the composition of metals in a bullet from the suspect's ammunition. a forensic scientist's analysis of the bullet shows that it contains 11.9 g of lead, 0.5 g of tin, and 0.8 b of antimony. what is the percentage of lead metal in the bullet? express your answers to the one's place.

Define dew point. i am writing this part to be able to ask the question

Which of the following is not true about the atomic model of substances?