One of the safety measures that almost everyone is aware of is to never add water over burning or boiling oil. What happens when you add water over burning or boiling oil? Why does this happen? What is the science behind it?
What happens when you add water to burning or boiling oil?
When water is added to burning or boiling oil, it causes the oil container to explode into a devastating fire as this Explosive Oil Fire video shows.
Why does this happen? What is the science behind it?
When water is poured over hot oil, it directly sinks to the bottom of the oil container. This happens due to:
1- density difference, the density of cooking oil is approximately 0.92 g/mL, this varies a little bit depending on the oil type, while the density of water is 1.00 g/mL
2- the immiscibility of oil and water, water and oil do not mix due to their different properties. Water molecules are polar while oil molecules are non-polar. Read through this article to know more about oil and water different properties.
Hence, when water is poured over hot oil, it directly sinks to the bottom of the oil container. Sinking water will heat up and immediately evaporate into steam and expand in volume. As a result, expanded water becomes less dense and moves up. Water movement and extra volume will push on oil and force it to explosively erupt in all directions. Afterwards, the scattered oil droplets will reach the fire source and ignite vigorously.