Ever looked at a blue, cloudless sky, and seen a jet plane fly across it, leaving a long, thin trail of white clouds? Have you noticed that passenger planes don't seem to leave any trail like that? Let's find out why.
If you look at an old pair of pyjamas or Bermudas, you might notice that the elastic has given way, and does not snap back into shape anymore. What if there was an elastic that never went out of shape? Well, there is, and it's right in our bodies!
Things made of plastic, from credit cards to spoons to bags, have become so common in our lives that we can hardly think of life without them. Yet all plastics are made from petroleum, which will run out in a few decades. What do we do next?