1 00:00:00,000 --> 00:00:04,100 We are running out of sand. That sounds insane. 2 00:00:04,100 --> 00:00:08,480 There are massive deserts all around the world that are just full of sand. 3 00:00:08,480 --> 00:00:12,160 27.7% of the Earth's crust is just silicon, 4 00:00:12,160 --> 00:00:17,960 a key component of silica sand. The problem is that not all sand is created equal 5 00:00:17,960 --> 00:00:23,000 and we use a lot of it. Over 50 billion tons of sand and gravel 6 00:00:23,000 --> 00:00:26,200 are used globally every year in paving and construction 7 00:00:26,200 --> 00:00:30,680 but also in Windows, screens, silicon chips and photovoltaic cells. 8 00:00:30,680 --> 00:00:34,440 And this massive sand demand has been going on for a long time. 9 00:00:34,440 --> 00:00:38,520 A 2014 UN report estimated that sand was 85% 10 00:00:38,520 --> 00:00:41,920 of all material mined globally by weight. 11 00:00:41,920 --> 00:00:45,440 Sand is formed by the gradual erosion of rocks 12 00:00:45,440 --> 00:00:49,640 into smaller and smaller grains. This is a process that takes thousands of years, 13 00:00:49,640 --> 00:00:54,280 making sand a renewable resource only in a very technical sense. 14 00:00:54,280 --> 00:00:58,240 Plus, that sand has different properties depending on how it was created. 15 00:00:58,240 --> 00:01:03,680 Concrete typically uses water-weathered sand because the resulting grains are rough and angular, 16 00:01:03,680 --> 00:01:07,920 which allows them to lock together. Wind-weathered desert sand, on the other hand, 17 00:01:07,920 --> 00:01:13,000 tends to be too round and smooth. Therefore, Dubai, despite being built on a desert, 18 00:01:13,000 --> 00:01:16,880 imports hundreds of millions of dollars of sand each year 19 00:01:16,880 --> 00:01:20,640 to support its rapid growth. As for the screen in front of you 20 00:01:20,640 --> 00:01:24,760 and the silicon chips inside your device, that's a slightly different story. 21 00:01:24,800 --> 00:01:28,320 Glass needs to be made from near-pure silica sand, 22 00:01:28,320 --> 00:01:31,840 sand that is at least 95% silicon dioxide, 23 00:01:31,840 --> 00:01:36,960 or your window is going to look just awful. It also needs to be extremely fine 24 00:01:36,960 --> 00:01:41,800 with grains between 0.075 millimeters and 1.18 millimeters, 25 00:01:41,800 --> 00:01:45,800 and it also has to be the right color. For more sophisticated industrial purposes, 26 00:01:45,800 --> 00:01:49,960 silica is extracted from rock quartz and quartz-rich sand, 27 00:01:49,960 --> 00:01:54,640 then purified into 98% pure metallurgical-grade silicon. 28 00:01:54,640 --> 00:01:58,640 Silicon for semiconductors needs to have a purity of 11 nines. 29 00:01:58,640 --> 00:02:02,840 That's 99% a decimal and nine more nines. 30 00:02:02,840 --> 00:02:06,160 The advantage of this process is that the geometry of the sand 31 00:02:06,160 --> 00:02:09,880 doesn't actually matter all that much, so desert sand can be used. 32 00:02:09,880 --> 00:02:14,840 That being said, natural sources of sand vary a lot in terms of composition, 33 00:02:14,840 --> 00:02:20,040 and easily accessible quartz-rich sand sources are still a limited resource. 34 00:02:20,040 --> 00:02:23,040 The global demand for sand is so intense 35 00:02:23,040 --> 00:02:26,600 that the industry has attracted attention from organized crime, 36 00:02:26,600 --> 00:02:31,520 and you know the situation is getting serious when a bunch of gangsters roll up and steal a beach. 37 00:02:31,520 --> 00:02:36,280 Sure, it sounds funny, but illicit sand mining can cause serious problems. 38 00:02:36,280 --> 00:02:39,400 Not only can intensive dredging of sand from rivers 39 00:02:39,400 --> 00:02:45,200 and the ocean floor damage local ecosystems, but irresponsible sand mining can erode supports 40 00:02:45,200 --> 00:02:49,400 from nearby structures and has resulted in multiple fatal bridge collapses. 41 00:02:49,400 --> 00:02:53,280 Now, we could massively scale down our use of sand, 42 00:02:53,280 --> 00:02:56,280 but we'd all still like to have buildings to live in, 43 00:02:56,280 --> 00:03:02,200 roads to travel on, and TVs to watch, and so the spice must flow. 44 00:03:02,200 --> 00:03:05,760 There are other options, though. We might be able to reduce the amount of sand we use 45 00:03:05,760 --> 00:03:08,840 by shifting to other sources of aggregate and silica 46 00:03:08,840 --> 00:03:12,400 like crushed rock, demolition material, and ore sand, 47 00:03:12,400 --> 00:03:16,680 a byproduct of the mining industry. Some have even suggested replacing sand 48 00:03:16,720 --> 00:03:21,680 with used, pyralized coffee grounds, which research has shown can even result 49 00:03:21,680 --> 00:03:25,040 in 30% stronger concrete in the right proportions. 50 00:03:25,040 --> 00:03:28,160 We also need to reuse what we've already extracted 51 00:03:28,160 --> 00:03:31,960 as much as we can. The bright side is that many processed forms of sand 52 00:03:31,960 --> 00:03:37,600 are basically infinitely recyclable. Around 80% of asphalt used in American roads 53 00:03:37,600 --> 00:03:42,680 is already recycled back into new asphalt, and glass can be broken down, tumbled, 54 00:03:42,680 --> 00:03:47,120 and turned back into sand. However, many forms of processed sand, 55 00:03:47,120 --> 00:03:51,920 such as rubber-like silicone polymers, can only be downcycled a limited number of times 56 00:03:51,920 --> 00:03:55,880 due to physical constraints, or they may be too contaminated to safely 57 00:03:55,880 --> 00:03:59,200 and economically recycle at scale with current technology. 58 00:03:59,200 --> 00:04:03,560 We also need to push for longer-lasting, repairable digital devices, 59 00:04:03,560 --> 00:04:07,880 because even the very cheap ones are made from materials that are ultimately limited. 60 00:04:08,960 --> 00:04:13,400 Life's a beach, and then you die. But first, you finish this video. 61 00:04:13,400 --> 00:04:17,800 Nice job. Hey, thanks for watching. Like the video if you liked it. Dislike it if you disliked it. 62 00:04:17,800 --> 00:04:22,400 Check out our other videos. We have many. And feel free to comment with video suggestions 63 00:04:22,400 --> 00:04:24,960 down in the description or in the comments. 64 00:04:26,480 --> 00:04:28,320 I need to go subscribe.