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Tomorrow Today - Houses Made of Straw and much more
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00:30Houses made of straw and more, this time on DW's Science Show.
00:36Welcome to Tomorrow Today.
00:41A bale of straw crushed by a concrete slab, a test of the material's general rigidity
00:49and ability to bear loads.
00:52Afterwards, this hydraulic cylinder applies up to six tons of pressure to see how much
00:58the bale deforms.
01:01Guido Morgenthal and his team at the Bauhaus University in Weimar are investigating whether
01:07large bales of straw are suitable for use as a construction material.
01:13He wants to build houses where it's not just an insulator in walls, but a load-bearing
01:19element in their structure.
01:20Buildings account for almost 40 percent of global CO2 emissions.
01:27That's why we try to use more sustainable materials.
01:30Straw bales can also bear loads, and construction with them is very attractive compared to timber
01:36frameworks.
01:37Compared to wood, straw grows back very quickly and can act as a CO2 reservoir in concrete
01:43applications.
01:44Along with mechanical testing, the engineers are also working on ways to help architects
01:51acquire approval for projects planned with the material.
01:55Until now, structures made with straw bales had to be approved individually in Germany.
02:01The aim of the load tests is to create engineering models for the mechanical behavior of a single
02:08bale.
02:08Then we use that to calculate the behavior of an entire wall, paving the way for future structural
02:15engineering regulations, which means the construction methods can be employed more widely.
02:22There's plenty of straw to work with.
02:25One German state's agriculture authority estimates at least 7 million tons of the material go unused
02:32in the country every year, so it would theoretically be available for house construction.
02:37Allowing for 50 tons of straw per house, roughly 140,000 of them could therefore be built annually.
02:45But it's still very early days.
02:49There are currently just 1,500 straw-based structures in Germany.
02:54One is this building currently under construction at a school that trains caregivers for nursing homes.
03:00It urgently needed to expand its teaching facilities.
03:06The building was designed and is being built by architect Florian Hoppe.
03:10The original idea was to bring in a container to provide two classrooms here.
03:19Then we suggested using straw bale construction because such buildings offer good insulation.
03:26They don't freeze in winter and don't sweat in summer, while containers do both.
03:31And when you consider the materials' recyclability, I think straw bales are much better in terms of
03:38ecological balance and compostability.
03:43Guido Morgental is visiting the construction site today to talk about how the straw bales will behave
03:50over time under the building's constant load.
03:53The practical projects bring us closer to transitioning from science to practice, providing important
04:01insights for widespread implementation.
04:05A key issue when it comes to that widespread implementation of straw as a building material
04:11is fire safety.
04:15I'm plastering the straw bale construction on the inside with clay.
04:20We need F30 fire resistance in these simple buildings.
04:24That means you have to be able to exit the building within 30 minutes.
04:29The highly compressed bales and plastering are thick enough to ensure the necessary fire resistance.
04:34Another question builders often ask involves thermal insulation.
04:42Stefan Helbig from the university's Materials Research and Testing Institute
04:47studies the thermal properties of straw bales.
04:50For researchers like him, measuring the thermal conductivity of masonry is routine.
04:57But straw-based structures are complicated.
05:00One problem is cutting specimens out of the thick bales to fit into his test rigs
05:05without damaging the bale's integrity.
05:09It's important to us that the texture inside the bale, the structure,
05:14is exactly the same as it is when used in practice.
05:18Only then are we measuring the same thermal conductivity.
05:23Another issue is the thickness of straw bale walls, which are up to 1.2 meters wide,
05:29a big drawback for cities where space is scarce and expensive.
05:34A team led by Katharina Ehlert and Kathrine Linner is therefore experimenting with additives like
05:40lignin, a by-product of paper production. It could help them reduce the thickness of straw-based walls
05:48without compromising their load-bearing abilities.
05:51This mixture of straw and additives is pressed and baked in an oven to produce a kind of brick.
06:02The researchers are already able to produce their straw bricks accurately and with precise edges.
06:10That simplifies plastering.
06:12As you can see, we're trying to make much thinner walls than with bales.
06:21There is one small disadvantage, though.
06:24We can't achieve quite the same energy efficiency.
06:29But that's almost impossible without having that 1.20 meter of insulation.
06:34Even so, our materials' ecological footprint is significantly lower than with conventional building materials.
06:46A 3D animation shows what multi-story townhouses made of straw could look like in the future.
06:53If load-bearing straw bale houses can be successfully established in both urban and rural settings,
07:00it could help massively reduce production costs for building materials and heating costs when the houses are finished.
07:11One heat record after another is being clocked up in Europe.
07:15The continent is growing hotter and hotter, especially during the summer months and especially in cities.
07:22As the blazing sun bakes the concrete and asphalt in high-rises,
07:26fine dust grows more concentrated in the walled-in streets between.
07:32More greenery can help cleanse the air of pollutants and lower temperatures.
07:37Research teams in Hamburg are studying exactly how it all works in a spectacular project.
07:43In the middle of Hamburg's St. Pauli district stands a gigantic bunker from the Second World War, 38 meters high, with sides 75 meters long.
07:57New floors built on top now house a hotel.
08:01There's even a park open to the public.
08:03It's also a kind of open-air laboratory for studying climate change and its impact on our cities.
08:10Different scientists help plan and execute the project.
08:15It's getting warmer and drier here, and that's clearly because less water is evaporating in the area,
08:21and we're losing more vegetation.
08:24In Germany, we have a staggering urbanization rate, a million square meters per day, and that can be offset.
08:31We want to find out what positive effects vegetation has on buildings in order to compensate for this land use.
08:43A memorial from the past that sets an example for the future.
08:47For Marco Schmidt, planning five additional floors with almost 10,000 square meters of green roofs and facades is a unique opportunity.
08:57Working scientifically often involves experiments conducted on a couple of square meters,
09:04but here we have a really large lab, a real building, and you can get much more out of it.
09:10We have to transfer results from a small scale to a large scale, and the bunker is ideal to do that.
09:17A private investor is planting 4,700 trees, shrubs, and hedges here, in the park open to the public and in front of the hotel rooms.
09:31Everything has to be hauled almost 60 meters in the air by crane.
09:35For the landscape architects, the height made deciding what to plant something of a challenge.
09:41The conditions here are like those on a mountain. You can feel it in the wind.
09:49There are strong winds, sometimes driving rain, extreme weather conditions.
09:54For example, we put a mountain pine here from the Pyrenees or the Alps,
09:58as well as juniper, which also grows in the mountains.
10:01These are trees that can cope well with the harsh climatic conditions up here.
10:10Planning might have been a challenge, but it pales in comparison to implementing those plans.
10:17Landscape gardeners usually work on the ground, not at dizzying heights.
10:22There's little space, you can't have many people in one place, and conditions are windy,
10:31sometimes gusting up to 65 kilometers an hour, which causes real problems.
10:36To conquer this inhospitable environment, nature needs a helping hand.
10:43We've installed steel mats across the entire lower level.
10:47Individual woody plants are secured to these steel mats with tension straps to prevent anything
10:53falling down during storms. The weight of the substrate also prevents the whole structure
10:59from blowing off, so it's also secure. Every plant that grows over the edge is also secured individually.
11:07Marco Schmidt laid more than a kilometer of cable between the plants, installing around 80 sensors
11:14to collect data on the effects of green roofs and facades. Cooling buildings with conventional air
11:21conditioning is inefficient and counterproductive. Their systems consume a lot of power and produce
11:28waste heat. Schmidt prefers natural cooling systems that work through evaporation.
11:35We want to calculate water balance, so measure how much water falls on the bunker site.
11:41And here we measure runoff. The balance helps us calculate evaporation, and that's what has an impact
11:47on climate. The idea of making cities more climate-friendly by greening roofs and facades isn't a new one.
11:56Similar projects have been implemented all over the world, like in Singapore. And there's one in Milan,
12:03in northern Italy, too. And other German projects include one in Düsseldorf. Still,
12:08the Hamburg bunker is unique in many ways. Some other greening projects are spectacular,
12:16such as the Bosco Verticale in Milan, or Kubürgen II in Düsseldorf. But we don't see any results from
12:23them at our conferences. How much water was used? Did it have to be treated? How much runoff was there?
12:31How much of it evaporated? All these conclusions that would influence future construction projects
12:37are missing. But that's what we're doing here. Then there are issues like heavy rainfall events,
12:46or increasingly long periods of drought and heat. As the climate changes, so do urban development
12:52requirements. The data obtained when repurposing this historic structure can provide a solid foundation
12:59for planning and designing today's buildings and the cities of the future.
13:08For some people, taking the elevator or the stairs is boring. When it comes to getting to the top floor,
13:14they want more of a challenge. They want to do it like Spider-Man, the superhero who climbs buildings
13:20using only his sticky hands and feet, and the occasional web. A 15-year-old in southern Germany was inspired to give it a go.
13:29Spider-Man fan Vincent Weigl has been tinkering for a year in his living room, with a goal.
13:49I thought, I want to climb like that, and there must be a way with all the technology out there.
13:53For a national youth science competition in Germany, the 15-year-old designed and developed a special suit.
14:02I first tried a rectangular shape for the suction cup, but that didn't work,
14:07because the corners were really hard to seal. It could hold hardly any weight at all.
14:13This was the third prototype. A much more effective shape, Vincent uses a 3D printer to produce many parts
14:22himself. Some of the work has to be done in the yard. He has the enthusiasm to stick with the thing
14:30and find out how it works without giving up. That's really important. It actually makes me a little teary
14:37thinking about it. To climb walls like Spider-Man, Vincent attaches a contraption to each arm and leg,
14:45made up of vacuum pumps, pressure sensors, microcomputers and suction cups.
14:53Each cup has its own module with its own battery, located here and here. It has its own miniature
14:59vacuum pump, located here, powered by electricity. The switches are thumb controlled. The upper one
15:07detaches the cup on the arm and the lower one detaches the leg.
15:10Vincent first climbed a wall at his high school. Anna Yendrusiak, who supervises the science
15:20competition projects, helped out. The entire community is proud of the young inventor,
15:25who now wants to found a Superman suit start-up.
15:31That doesn't happen very often, that you find companies that want to participate and support you.
15:37Vincent has already found a company that wants to support him, which is really great.
15:46Vincent hopes to one day sell his special suit to commercial climbers, rescue workers and trades
15:52people. And to people who just want to have fun, because it's just so cool.
15:58A young German researcher who wants everyone to have the chance to act like a superhero.
16:07Just a few years ago, bouldering was pretty much a fringe sport. Now it's trendy and climbing gyms
16:13are booming. All the action happens at heights from which you can jump down without much risk.
16:21And if you do fall, you land on thick mats. Bouldering can help people build self-confidence and learn to
16:28overcome their fears. Therapists have now even developed treatment concepts based on it.
16:38For a decade now, bouldering has been one aspect of therapy for depression at this clinic in Erlangen in
16:44Germany. Psychotherapist Katharina Luttenberger has played a pioneering role in integrating the
16:51approach and providing scientific support for it. With bouldering, we get right to it. I don't have to
17:01beat around the bush with patients for a long time. We do an exercise and boom, something happens.
17:12The therapy has been good for Erika Schneider. She's suffered from depression for the last seven years,
17:20ever since her son took his own life at the age of 25.
17:28You always ask yourself, should I have noticed something? Could I have noticed or done anything
17:33to prevent it? To deal with her feelings of guilt, she finally sought professional help
17:44and discovered Katharina Luttenberger's unique approach. The psychotherapist was looking for
17:53volunteers to participate in a study on bouldering as an aspect of treatment. It all starts with
18:01choosing the right climbing shoes. They have to be a good fit. To climb without ropes or harnesses,
18:11you have to be completely focused. That's precisely why bouldering can be a good fit in a therapy plan.
18:24When I'm bouldering, I'm completely in the moment, thinking about nothing. It's like a weight has been
18:30lifted from my shoulders or fallen away. This is particularly special in a therapeutic sense,
18:37because we get to mindfulness kind of through the back door. Nobody hangs on the wall thinking
18:43about what to make for dinner. Hanging on the wall, you're completely in your body,
18:48at the most looking at how you can reach your next hold. Today, Luttenberger wants to do an exercise
18:56called bouldering blind. Her approach combines specific therapeutic topics with elements of the
19:05rock climbing discipline. In this variant, she leads the blindfolded patient by the hand over the root.
19:15Blind bouldering is about self-awareness, fear and expectations about your performance.
19:20The therapist is there to help, but also to remind the person in treatment to focus on their body
19:31and what they're feeling in the moment. Erika Schneider goes from being tense to feeling more relaxed.
19:41When blind bouldering, as we just showed, people often think a lot beforehand about how dangerous it could be,
19:52or how afraid they might become. Especially people who suffer from anxiety or depression
19:59often think things in advance, like, I'll never be able to do that, or what happens if I can't find a hold?
20:05That can easily be transferred to real life. An exercise with a partner focuses on cooperation,
20:18responsibility and interdependence, not to mention good communication. Participant experiences while
20:26bouldering are highly individual. Some feel joyful, but emotions like fear, frustration and pride are also
20:34common. Depression is often a feeling of numbness. People say they don't really feel anything anymore.
20:43Everything is gray and somehow bad. They don't feel any real intense emotions anymore. All of those are
20:49somehow just under wraps. That's why we don't view emotions as good or bad here, but instead try to get
20:57back in touch with our feelings and emotions through bouldering therapy. Katharina Luttenberger's study in the
21:06field looked at how effective bouldering psychotherapy was in over 200 participants. She compared the new
21:14approach with established cognitive behavioral therapy and a control group that exercised alone at home.
21:22And the results indicate that bouldering therapy works. In the subjects who had it as part of their
21:32treatment plan, depression severity decreased significantly over time, as shown by the steep
21:39drop in the blue line. Subjects from the cognitive behavioral therapy group, shown here in brown,
21:47performed slightly worse. Pursuing physical activity alone was even less effective.
21:56Based on the positive results, bouldering psychotherapy has now been permanently integrated
22:01into the range of therapies offered by Erlangen University Hospital.
22:09But not everyone has to go bouldering. We just want to use bouldering psychotherapy to expand the range of
22:15possible treatment options. For Erika Schneider, bouldering shortly before the anniversary of her
22:23son's death proved to be a positive experience. My brain is focused just on climbing and it's really
22:33relaxing. Not just physically, but mentally as well. It's amazing. I wouldn't have believed beforehand
22:40what a difference it can make in how good you feel. I feel really good again right now.
22:48See you again next week.
22:53Does it make a difference where in the world you climb? Is it easier to defy gravity in some places
22:59than others? Great question, which this time came from our viewer Ola B in Egypt.
23:04Does gravity differ depending on where on Earth you are?
23:14Gravity, also known as gravitation, is a fundamental physical force that acts on all objects with mass.
23:22On Earth, it causes things to fall to the ground. It's also why the air in the atmosphere
23:29doesn't fly off into space. The greater an object's mass, the stronger the force of gravity acts on it.
23:38But don't confuse mass with weight. The mass of an object describes the amount of matter it contains,
23:45and that remains the same wherever the object happens to be. Its weight on the other hand depends
23:51on the force of gravity affecting it. An example, the mass of an astronaut on the Moon doesn't change
23:58when they fly there, but they weigh just a sixth of what they weigh on Earth.
24:06For three reasons, your weight can also change depending on your location on Earth.
24:11First, because Earth is not a perfect sphere, it has lumps. The distance from the center of the Earth
24:17to the surface is also greater at the equator than at the poles, so gravity is weaker at the equator.
24:24The Earth's rotation amplifies this effect because centrifugal force is greater at the equator than at the poles.
24:33Second, there's elevation. When an object is at a great height, for example in an airplane or on a mountain,
24:40the distance to the center of the Earth is also greater, and the force weakens with distance.
24:46So the higher you go, the less gravity affects you.
24:53Third is geology. Earth's composition also influences gravity.
24:59Dense deposits of materials with lots of mass, for instance, can increase gravity locally.
25:07All this means you would weigh around half a percent more at the poles than at the equator.
25:13So even though we hardly notice the differences, gravity on Earth isn't uniform.
25:24What are stars made of? How many colors can butterflies see? Could robots have babies one day?
25:32Do you have a science question? Then send it to us as a video, text or voice message.
25:40If we answer it in the show, we'll send you a little gift as a thank you. So, just ask.
25:48And that's all for now. We hope you enjoyed the show.
25:51See you again next time on Tomorrow Today. Bye-bye.
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