Everyone can see the rocks and pebbles – but can you find the golf ball hiding among them in under 10 seconds?

1. Shake Things Up. Most often, a piece of sea glass isn't just sitting on the top of the pile of sand or stones waiting for you to find it. You need some techniques to guide your search.

In Cornwall, some beachcombers had been uncovering thousands of plastic rocks and pebbles. Using X-ray and infrared spectroscopy, Dr Turner discovered they comprised of polyethylene and ...