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FunTranscript
00:00That was Serbian.
00:03When Christoph was riding his bike the other day,
00:06suddenly there was a bang.
00:08Oops! What was that?
00:13A hole in the road.
00:15A pothole.
00:19Where could that have come from?
00:23You have to investigate that, says Christoph.
00:26First you need a piece of road.
00:31Here you are.
00:33A piece of road.
00:35To be more precise, four of them.
00:41It starts with two.
00:43In a very special room.
00:45An air-conditioning chamber.
00:47Here you can produce winter weather.
00:49You have to dress warmly.
00:51Because potholes are mainly formed in winter.
00:55Another ramp, so that a car can pass over our road.
01:01Close the door.
01:03Because now it's getting cold.
01:07Really cold.
01:12Minus 30 degrees.
01:15That's where the cold air blows in.
01:18It's really cold.
01:20It's really cold.
01:22It's really cold.
01:24It's really cold.
01:26It's really cold.
01:28It's really cold.
01:30It's really cold.
01:37To make it even harder for the pieces of road,
01:40the helpers load sandbags into the car.
01:43It's really cold.
01:57Close the door.
01:59Here we go.
02:02The car now drives over our pieces of road
02:05several hundred times.
02:07Back and forth, forwards and backwards.
02:10Again and again.
02:13And again.
02:23And the result?
02:27Rather disappointing.
02:31The pieces of road still look the same as before.
02:34What to do?
02:36This time all four pieces of road have to go.
02:40Actually, what cars can withstand is tested on this test bench.
02:44But why not see what happens to a road?
02:49Hardness test.
02:50Not only for the car and its suspension,
02:52but also for our pieces of road.
02:56First it wobbles.
02:58Then it cracks.
03:01Heavy blows.
03:03Shake again.
03:06And? What happened?
03:10Indeed, a crack has formed.
03:15A crack where water can penetrate the road.
03:19And that's not good, especially in winter.
03:22Water has a very special property.
03:25You can observe that in this refrigerator.
03:28The water in the bottle is cooled down to minus 40 degrees.
03:32Most substances become smaller in the cold.
03:35Water does not.
03:37Water expands.
03:39Even if it hasn't frozen yet.
03:42A packet.
03:44It contains water molecules,
03:46i.e. models of them.
03:48They easily fit in there.
03:51When the water is cold,
03:53the molecules are separated.
03:56But when water freezes, it forms ice crystals.
04:01The molecules can only be put together in a specific way.
04:06Even when they are put together, they become more sparse.
04:13In the end, our molecules no longer fit into the box.
04:21No chance.
04:24So, the water expands when it becomes too cold.
04:32It can release a lot of force.
04:35It can even really blow up the bottle,
04:37even if it hasn't frozen yet.
04:48Look at that.
04:50It was just water and a little ice.
04:53If the water then drinks through such cracks in the road
04:57and freezes and becomes ice and expands,
05:00of course, it can destroy the road.
05:03In winter, a road like this freezes very often
05:06and a lot of cars drive over it.
05:09Really a lot of cars.
05:12A lot of cars.
05:15Then a small crack can become a pothole
05:19with the help of frost and many cars.
05:22The more water it collects,
05:24the more damage it can cause when it freezes.
05:28So that the roads don't just consist of potholes at some point,
05:32they are repaired.
05:34Then comes the pothole team.
05:40First saw.
05:45Then shovel out the old asphalt.
05:53Burn dry.
05:56A layer of glue.
06:01Then fresh, hot asphalt.
06:06Roll smooth.
06:11And a little more sand.
06:15And the road is like new.
06:20Perfect.
06:22Christoph thinks so too.
06:44Oh!
06:48Oh!
06:58Huh?