Science, Tech, Math › Science Trading Places: Liquid Science Magic Trick Share Flipboard Email Print Anne Helmenstine Science Chemistry Activities for Kids Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated November 13, 2019 Here is a quick and interesting science trick for you. Take two glasses of different-colored liquids and watch the liquids switch places in the glasses. Magic Trick Materials This science magic trick or demonstration can be performed using many different liquids, such as water and wine, water and oil, or water and whiskey. All you need are two liquids that have different densities. If the liquids don't mix (such as water and oil), you will get a clearly-defined separation. Expect some mixing of water with rubbing alcohol or an alcoholic beverage. You can tint water or alcohol-based liquid with food coloring. Two small identical glasses, such as shot glassesWaterOil or wine or whiskey or rubbing alcoholA thin waterproof card, such as a driver's license Perform the Liquid Magic Trick Fill one glass completely full of water.Fill the other glass completely full with the other liquid you selected.Place the card over the water glass. While holding the card onto the glass, flip the water glass over and set it and the card on top of the second glass.Line the glasses up so that they are even and move the card so that there is just a tiny bit of open space at the edge of the glasses.Over the next few minutes (about 10 minutes for shot glasses), the liquids will exchange places. The alcohol or oil will rise to the top while the water sinks and fills the bottom glass. How the Liquid Magic Trick Works Well, obviously not by magic! This is simple science. The two liquids have different densities from each other. Basically, the lighter liquid will float while the heavier liquid will sink. You would see the same result if you had removed the card entirely, except this way is prettier and looks more magical.