Is there evidence that sea floor spreading really happens?

Answer 1

The evidence exists in the extrusive igneous rock, basalt, on the ocean floor near the mid-oceanic ridges. The magnetic orientation of the Earth is recorded in the igneous rock at the time of its formation. The orientation of Earth's magnetic field changes over time, and thus provides a way to relatively date rocks. These orientations can be recorded and mapped with the aid of a magnetometer. Magnetic orientation of oceanic crustal rocks on one side of the mid-oceanic ridge appear as mirror images to the magnetic orientation of oceanic crustal rocks on the other side, meaning that the seafloor is spreading in opposite directions from the rift zone over time. Modern instruments have measured the movement of crust away from the rift zone and it roughly approximates the rate of human fingernail growth.

Answer 2

Yes, we can measure the spreading with modern laser and satellite equipment. The spreading is also evidenced from bands of magnetic anomalies which are caused from the ocean crust forming during alternating magnetic polarities of the earth.

Answer 3

"Accurate measurements of the distance between landforms by global positioning and laser measurement have demonstrated that sea floor spreading and the movements of plates does exist."