Dana designs an experiment to test the speed of sound waves as they travel through different materials. Her research question is, "How do different materials affect the speed of sound waves as they travel? What would be the test (independent) variable in Dana's experiment?
O amount of time it takes the waves to go through the material
O type of material
O the tool used to measure the time
O the object used to make the sound

1. why does the same side of the moon always face earthc.the rotational period of the moon is equal to one revolution around earth2. which is greater the moons period of rotation or its period of revolution  b.the moons revolution period around earth3.what was the major accomplishment of the apollo missions  c.sending the first human into space4. which of these space missions involved the deployment of lunar roversa. voyager 15. which scientists are going to explore next on kepler-186fd. evidence of existence of life6.which mission is not going to explore the outside of the solar  systemb.safir7.which technology limit the future of space explorationb. scientist must first develop certain technologies before missions can be completed.