How can you make oil sink in water?
An object will float or sink in a liquid, depending on its density. Density is a property of matter that tells us how heavy something is for its size.
For oil and water, liquids deemed to be immiscible. But still, oil can sink in water. How? There are several ways. One, you can opt for oils that have higher density. Two, you may choose to apply heat to oils with low coefficient of expansion. As you heat the water, its density will decrease whereas the density of the oil will more or less remain the same. The oil will sink as soon as the water’s density decreases to its lowest point, well before it boils. Lastly, you can mix the oil of your choice with an ingredient that cann increase its density. The same principle works for saltwater. The reason it is denser than freshwater is due to its salt content
Lava lamps, or liquid motion lamps were invented by Craven Walker in 1964. Filled with liquid and a special kind of colored wax, this lamps glows when the bulb, set at the base, is switched on. The bulb heats and melts the wax, causing it to float to the top of the lamp. When it cools, it sinks to the bottom, and this cycle is repeated over and over.