Identify the medium in each example below . 1.when a pebble is thrown in a pond ,water waves form .

2. Sound waves travel through the air from a speaker to your ear .

3. When you move your hand up and down while holding a jump rope ,you make a wave .

Avariable that is not being directly tested during an experiment should be changed varied experimented controlled

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?

Which statement best summarizes the importance of ernest rutherford’s gold foil experiment? it proved that all of john dalton’s postulates were true. it verified j. j. thomson’s work on the atomic structure. it showed that an electron circles a nucleus in a fixed-energy orbit. it showed that a nucleus occupies a small part of the whole atom.