Simple density experiments you can try in your kitchen now. We started by putting a glass of water on top of a glass of vegetable oil. That is a cool experiment on its own, but let's focus on density here. After we moved the card that separated glasses a little bit to create a small gap for liquids to connect, water and oil started moving. In the end, we had oil in the top glass and water in the bottom glass. It was time to turn our structure upside down and watch the flow of these liquids again. It can continue forever as long as you continue flipping glasses. But then we tried the same experiment with four liquids: water, coloured rubbing alcohol, handwash and oil.