How do penguins feathers work?

In our science work this week we were looking at how penguin’s feathers work. We learnt that penguin’s feathers are waterproof because of the oil they produce.We had a penguin outline and used a wax crayon to produce a wax coating. We then dropped water onto the penguin. We found out that the water stayed on top of the coating just like water stays on top of the penguins feathers.