Density Demonstration

Materials required:

- salt
- salad oil (olive or Sesame oil are best)
- tall glass
- cold water

Procedure:

1) fill the glass over 3/4 fully with cold water.
2) pour some oil slowly into the glass upto 1 inch above the water. Because oil is less dense than water, the oil floats.
3) Spray generously salt on the oil and the observe.

Inference:

Oil is less dense than water, it floats. Salt is denser than water and oil so it sinks.
However while sinking oil sticks to salt crystals and become more denser as it reaches the water. So the oil that stuck with the salt crystal sinks along with the salt.

As soon as the oil and salt drop gets to the bottom, the oil being lighter splits from salt and comes up again to float. This happens to each salt crystal sprinkled. This experiment demonstrates the difference in the density of 3 materials – salt, oil & water. When this phenomenon is seen in a dark room with the glass lit with a colored light from the back, it looks magical.