What's Underneath Sand and Desert Sand?

There are an estimated 7.5 quintillion grains of sand on Earth's beaches. In this video we dig straight through them, past the point where the sand turns wet, past the point where the shovel stops, and then do the same thing in the middle of the Sahara, where what we find isn't what most people picture at all. Along the way: why beach sand and desert sand aren't the same substance, what the dunes are actually resting on, and the thing scientists found buried under the world's largest hot desert in 2010 that rewrote what the Sahara used to look like. CHAPTERS 0:00 – What Is Under Beach Sand? 0:46 – What Sand Is Made Of 1:21 – How Beach Sand Forms 2:18 – How Desert Sand Forms 3:39 – Digging Down: The First Layer 4:30 – Where the Digging Stops 5:23 – How Deep Is Desert Sand? 5:49 – What the Sahara Is Really Made Of 7:09 – Buried Under the Sahara 8:29 – Why the Sahara Changed 8:54 – Buried Forests & Sinkholes 9:46 – The World Beneath the Sand What is sand • quartz and feldspar • beach sand vs desert sand • groundwater • sand dune formation • Sahara Desert facts • prehistoric climate shifts • Milankovitch cycles • sinkholes • buried forests • Earth's deep history