Clean out the plastic bottle. You can use a small 16-ounce soda bottle or a larger 2-liter soda bottle. Use smaller bottles for smaller kids so that they can handle the bottle easier.
Use the funnel to fill the bottle 1/3 full with water.
Allow the children to choose what color food coloring they want to use, then add several drops of the selected food coloring to the water. Blue is popular, since it represents the ocean. However, children can be creative and make their water whatever color they'd like.
Have the children add glitter, beads or seashells to their bottle.
Top the bottle off with baby oil. There should be only a small space between the top of the baby oil and the top of the bottle.
Use a hot glue gun with a hot glue stick inserted to secure the lid to the bottle so the children cannot open the wave bottle.
Swirl and shake the bottle to create waves. Put on music or start a marching band and allow the children to show off their wave bottles.