Since it is a wave, we can make an analogy between radio waves and water waves. The figure at the left shows a scenerio where water waves propogate from a single center point by the a ction of tossing a rock into the water. Radio waves cause electrons in an antenna to surge back and forth the same way that the ripples in a pond case the the water to move up and down. J ust like light waves, radio waves travel in straight lines. Radio waves can reflect off of surfaces, such as layers of ionized gases in the ionosphere.
Radio waves reflect off of surfaces the same way that water waves do.
The reflection of radio waves is shown in the figure below. Here, radio waves are reflected off of the ionosphere and the Earth. Radio waves, however are not shaped like the circular water waves. Radio waves typically are domed shaped as shown in the picture to the right. These domed-shaped waves radiate from a transmitting antenna in all directions.