How do oil, water, and food coloring make silent underwater fireworks? Find out in the experiment below! What you need: Food coloring Vegetable oil Water How to make silent fireworks: Fill a large vase with water. Pour a layer of oil on top of the water. Drip food coloring onto the oil and watch the show begin! What’s going on? Food coloring is mostly water, and water is denser than oil. The oil floats on top, while the droplets slowly sink and burst into the water below. The falling droplets create colorful currents that mix and join together in swirls beneath the still surface, making them look just like fireworks!