How To Make Snow
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How To Make Snow

November 16, 2019


TOM SCOTT: The Youth Winter Olympic Games have brought me over to Lillehammer, in Norway. It’s still early in the season here, so they are making snow. Because getting these slopes to competition
standard isn’t easy. ROGER HJELMSTADSTUEN: Here in Hafjell we have
about 250 snow guns They’re all controlled from a big control
room and they all are connected together. It’s a lot about planning. To put the guns
at the right place. It’s about wind, if you put it on the wrong
side it’s going to be a lot of snow in the trees. That’s why we have two teams working night
and day the whole fall, the whole winter, to make
sure everything is perfect. TS: Here, in the snow gun, huge amounts of
water and air are being forced through tiny nozzles, creating a fine mist that freezes into fresh
powder. But while the weather is cold, the temperature is actually not quite below
freezing here. So why does this water freeze into snow? Why doesn’t it just… rain? Okay. Physics. As water evaporates, it sucks heat from the
surrounding environment. Put some water on your hand and blow on it, and the wet part will feel colder because that evaporating water is sucking
the heat away from your body. That’s what’s going on here. Some of these water droplets evaporate, so they drop the temperature around them. Which means other droplets might start to
freeze. And once that’s started, you get what are
called nucleation sites: the start of snowflakes. And if it’s not quite working efficiently
enough, then you can buy a kind of protein slurry. You add it, very diluted to the water, and suddenly every droplet is a nucleation
site and can form its own snowflake. RH: To make snow, we have pipes for water
and pipes for air. On top of that, every cannon needs a computer
cable. The water here in Hafjell comes from big lakes
at the top of the mountain and from there it’s natural pressure going
down. That’s the easiest and least expensive way. During a normal season, we use about 30,000
litres a minute. It sounds a lot, but we have a big, big lake so during the whole season it’s about 5-10cm
down and that’s if no new water is coming in so most of the time, it just looks like it’s
not touched. TS: The drier the air is, the more water can
evaporate into it. So if the air is really, really dry, 0% humidity, you can make proper snow when the air temperature is well above freezing, anything up to 6°C. But if the air is humid, there is nowhere
for those droplets to evaporate to. At 100% humidity, when the air is saturated, the temperature has to be -2 or lower to make
snow. ‘Cos this isn’t some kind of instant magic
freezer. The laws of thermodynamics pretty much make
that impossible. Much as it’d be great to have a snow gun that
works in the middle of summer all you’re going to end up with then… …is a rainmaker. RH: So, snowmaking is really important for
big contests, but it’s also really important for just the average day here in Hafjell with normal
people. It’s what we need to make this mountain work. Without it we’d be nothing. We need snow! TS: There’s a load more videos over on the
Olympics channel and on my channel, go check ’em out, go subscribe, and thank you to the Youth Winter Olympic
Games for bringing me out here to Lillehammer. [Translating these subtitles? Add your name here!]

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  1. As many people have said before this is a great way to handle ads. I also appreciate the little "ad" in the thumbnail so we knew what was coming before clicking on the video.

  2. Sorry Tom, had to happen eventually, but this time I knew this one, I had some time in Finland inside the Arctic Circle and we had to query why on earth they were making snow.. even though we were standing in more snow fall than England had seen in many years combined

  3. The sneaky thing is that you actually came to norway without telling me so I could tell you about, and show you around this awesome country!
    I used to go to hafjell as a kid, it's an awesome playground!

  4. Been a subscriber for a while now, absolutely love your videos, totally unique, interesting and great fun to watch, keep it up Tom!

  5. Wow, I always assumed those things had some sort of refrigeration on board. "Things you might've thought you knew, but really didnt."

  6. Great video ad and still informative. As long as it doesn't turn into the Oreo vids of 2014-15 everything looks good. you should do a video on the history of trademarking in light of the fine bros incident. It would be interesting to see the facts of past incidents without taking side.

  7. So… what you're telling me is that this was filmed in above 0 temperatures, and you needed that hat and mitts and heavy coat? Hahahaha, sincerely, a Canadian.

  8. You should have commented on the environmental costs of those snow guns.

    The guy said that "it sounds like a lot" of water they use but they have "a big lake" that, through the snow guns, 'only' drops about "5-10cm".

    One word: wtf. 30kl/min is a lot. It is. And if their big lake drops 5-10cm that is enormous amounts of water.

    And this doesn't even mention the electricity costs.

    I've read a few articles about snow guns and their effect on the alps. Just look it up. Those things aren't good for nature.

    Some seasons just aren't meant for skiing

  9. Great ad, but I probably still won't buy an Olympics. They're awfully expensive, and don't really go all that well with my existing infrastructure. Also, it's kind of too late to buy the one they were trying to sell me on. I am in the market for some light rail, though, so if you're thinking of advertizing some of that, you might get a sale.
    -Boston

  10. We use the same thing here in the southern california desert (I live about an hour's drive north from california city) as inexpensive air conditioning, called a swamp cooler. Water is pumped over a pad that air is blown through. The evaporation of water in the low humidity conditions will reduce the temperature from over 110F (44C) to about 85F (30C) using only the about of electricity to run a small blower. It does use quite a bit of water, and only works in very dry places.

  11. I suspect the compressed air component of the the mix decompressing as it exits the nozzles would enhance the cooling effect of the evaporation.

  12. Didn't even realise it was an advert until I read the comments. If you can keep pulling that off then I don't see what could be complained about 🙂

  13. If the air is forced out at high pressure, won't adiabatic expansion result in cooling as well? I would imagine at high enough pressure, the machine should work in a 100% humidity, above zero temp.

  14. Props to whoever made the Swedish Subtitiles, I don't need them but left them on to see how good they were and they felt spot on all the way trough. Well done.
    Also nice video Tom. 🙂

  15. whoooaaaaa, how many time I've been outside? look at ur video now boy, getting that high quality and sharper image! love it!
    1080p60fps pls?

  16. OK, so the water freezes in above 0 temperatures because some of it evaporates and cools the remaining water to below 0. Now for my question since the temperature is above 0 why doesn't the snow on the ground melt????

  17. For the first time ever I find myself wanting to watch another 'ad' – so I went ahead and already checked out the bonus links. This is a prime example of how to balance high-quality content whilst subtly promoting a product. The 'AD' in the thumbnail is classy, and your transparency is hugely appreciated. Other creators and advertisers need to watch this and learn. I genuinely hope this series helps you to convince other channels to let you produce advertorials for them in the future; if the content is always this good, I'm certainly always going to watch them.
    – Ross

  18. Tom, your videos are great. You are doing very important work! Please never forget how much we need you and more creators like you. Keep making these. ♥

  19. Couldn't you, at least in theory, dehumidify the air going in (and cool it down) before blowing it on the water? It would take a lot more power, I guess.

  20. It's a shame they do this and waste so much energy, rather than just hold the Olympics somewhere where there is natural snow

  21. I was walking in the Cairngorms a little before Christmas, and ended up coming back in the dark. The only way back into the car park at the ski center involved walking through the path of two of these things, in the dark, after a very long day. I don't think there was a single part of me not covered in the coldest water you have ever felt. Horrible!

  22. he said theres water and air lines, but last time i checked, fan guns dont use air lines, they use a fan and an air compressor… 😀 hehe

  23. Can you talk about the app the UCI claims to able to use to scan bikes
    for mechanical doping a.k.a. a motor in the bike? You would think that
    they could just make the motor on the bike not give off any signals. The
    only signals it really has to give off is an electromagnetic value and
    how could the UCI use ipads to scan for that?

  24. I didn't even know this was an ad until I saw on my homepage that it said "AD" in the top right of the thumbnail. It's awesome that it didn't feel like an ad, at all. This is just the kind of video I would expect from this channel and it was presented in just the same way others were. Glad you're getting some more back for your awesome videos 😀

  25. Used to fly in Alaska Bush. Lived in a village called Bethel, AK. One cold winter night was probably about 20 below(that's Fahrenheit). I took saucer pen with about 1/8 of an inch of water in it to a boil. Ran out to the front porch and through the water as hard and as high as I could with the pan. Made a very loud noise. Not gunshot loud. But very noticeable. It sounded a lot like, like putting something in hot grease. Made a very big steam cloud. So it was hard to tell what happened to all of the liquid. But I could not find any obvious indents in the snow where I had done this. I don't know if this water turned into snow or not. Is that the same or was that something different. Wondering because of the high heat involved.

  26. You don't own the rights to this video? Can you make ad revenue off of this? Or does the Olympic Committee not want ads on their promos?

  27. Having been an avid skier for many many years I can tell you that man made snow is NOT powder, in fact it is quite crappy. Better than skiing on rocks, but still, natural snow is much much better.

  28. Thanks for producing this – you kinda beat me to the chase. Anyway, either way, my sister is gona get educated later today!!!

  29. I like this show because it tell me things I generally don't know but oddly enough just before watching this video I mete a guy who makes snow for a living and he told me all about it… huh, I guess I did know this one by chance.

  30. I'm sorry but why don't they just host competitions, I don't know, in places where there's actually enough snow??

  31. I'm really late to the party, but how exactly does evaporating water suck heat from something that is colder than itself? Doesn't that break physics laws?

  32. Considering how the Olympic committee is almost as sue happy as the NFL, I lost a little bit of respect for you. I mean, when you really get down to it, no one should own the Olympics, since they started in ancient Greece. Talk about keeping something from going into the public domain.

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