Do we really need 8 glasses of water a day? How does a jet engine work? Where does earwax come from? Why are some apes vegetarian when we're not? We find out the answers to all these questions, as well as discover what thunderflies are, investigate if we're any closer to a malaria vaccine and discuss why bird feathers are so colourful. Plus, we find out about a newly discovered chemical that promotes cell survival in our brains!