Use a balloon as a model to demonstrate that the galaxies are expanding in all directions at the same rate. Blow a small amount of air into a white balloon. Using a permanent marker, add colored dots all over the balloon. Once the marker has dried, blow up the balloon fully. The dots will separate from each other at the same rate.
Bake two loaves of raisin bread after adding raisins to the batter. When the bread has been baked and has cooled, slice each loaf in half width-wise and compare the two. It can be seen readily how the raisins have moved outward in all directions in the loaves. Use this as an analogy for the expansion of galaxies in the universe.
Open up a black umbrella and paint white dots on the inside. Keep the umbrella open while the paint dries, then close it. As students watch. open the umbrella just slightly, then have a student stand underneath it. While looking upward, he will be able to watch the "universe" expand as you open the umbrella fully.