A bowl of water, two paper boats. You're trying vinegar, we're trying cream. Aha, the cream works. Why? It changes the surface tension. Cream and milk are first class sources of nutrition. That's why there's a glass and a half of full cream milk in every 200 gram block of Cadbury dairy milk chocolate. Are we agreed? Yes, Professor. Only Cadbury has that famous glass and a half. So when you think of chocolate, think of Cadbury.