Lava wave machines are bottled mixtures of water and oil substances. When you turn the bottle, water and oil substances do not mix; they roll, looking like ocean waves. Lava wave machines are a fun way to teach a class or scout group how the ocean works because the building materials are inexpensive: you can find them at most grocery and craft stores. Because lava-style lamps and wave machines were invented in the 1960s, they also make great retro decorations.
Fill your plastic bottle 1/3 full of water.
Add food coloring to the water until it is your desired color.
Fill the rest of your bottle with mineral oil.
Tightly close the lid of your bottle. Secure the lid with glue if desired. To watch the waves roll in your bottle, slowly tilt the bottle back and forth.