Science

Once you start thinking, things can get complicated. Especially when you think in terms of science on a world cycling tour.

I thought to myself, maybe I could look at such a bicycle world tour from a scientific point of view. But the German word Wissenschaft covers all academic disciplines. This also includes the humanities and social science. But my idea actually only referred to the natural science, physics, biology, chemistry, but also to the environmental science and/or medicine.

The word science covers precisely these disciplines

So let’s take a look at our bicycle world tour from the perspective of what we can gain through observation and logical reasoning. In other words, from the perspective of science.

SCIENCE IN 1808

As early as 1808, the country doctor Dr. Oberlechner reported on the effectiveness of waterfalls in a newspaper article. He marveled at the cascading masses of water, looked at the waterfall and saw the water of the stream divided partly into the finest dust and partly into countless drops. He found that the beneficent nature was providing the most splendid splash bath in the world for free: “…for the splash bath of the waterfalls surpasses all remedies for nervous weakness, which arises from city life, much sitting, headaches, annoyance, sorrow, disorderly eating or sleeping habits, abstinence from meat dishes, strict diet, self-pollution, novel reading and sentimentalism.” 

Aha, that’s scientific. That is science? But he was proved right. There was a real study on this at the beginning of the 20th century and the positive effect was empirically proven.

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We are more like Dr. Oberlechner

When we set off in April 2022, we didn’t know what was in store for us. We began to observe ourselves. Our thoughts, our moods, our hunger pangs, our weaknesses, our plans. I imagined how dormant guardians in our organs (organs, a system of breathing, nerves, digestion, cardiovascular system, muscles, skin (no claim to completeness)) had become a little rusty in the last few years before our journey. There was always enough energy in the form of food, more than enough. So there was no dispute as to whether it was better to store it for stockpiling or use the energy for current consumption.

And then suddenly there was a lot of excitement in our organs. The discussion began about how to use the energy supplied. Because the depots wanted to keep filling up, but those responsible for the muscles, for example, now needed more energy supply. When the dispute between the parties slowly subsided and an agreement was reached, which really felt like it took months, the daily routine was reorganized, the little people signaled at the right time that supplies were needed and we took care of it. It became difficult when we took breaks. Again, they hadn’t expected it. The feeling of hunger continued to be signaled and finally the fat deposits could be properly stored again. Ha, but we only went along with this to a limited extent. So there were new discussions about how to deal with this and a solution was found. No more information about hunger.

And then we set off again and the game began anew

It must have taken a year for the body to adjust to this constant change. The feeling of hunger was no longer so strong during our breaks of several days, but when we started again it was immediately signaled that more energy would soon be needed.

After 2 years, it was noticeable that I said “I’m hungry” more often than ever before in my life. I had learned to listen to the signals in my body and my body had learned to quickly translate the situation, whether it was a break or a big activity.

Well, I’m still unreasonable when it comes to chocolate, croissants or ice cream. Otherwise, I am surprised at how well we eat when we “listen”. Our body tells us what we need when and how much.

It feels good, strong and healthy. No more fights that use up unnecessary energy or divert it to the wrong departments.

We have a portion of fruit, 2 eggs, rice, vegetables and beans or lentils every day. We eat oatmeal, nuts and dried fruit. Pasta is on the menu every day if we need a lot of energy over a longer period of time. We had the best time eating on the streets in Indonesia. Their street food is incredibly balanced and there are always vegetarian options with tempeh and/or tofu. Followed by India, at least the southern part of the country, where it is not normal to eat animals. There is therefore a large selection of vegetarian dishes. We were not quite as impressed by South America. There is too much fried food on offer and this is a form of energy that can be stored but does not give us more energy. On the contrary.

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Perhaps a few more facts about our bodies.

There are 206 individual bones in our bodies. There are also joints, cartilage and ligaments. That makes up our skeleton. Then there is the musculature, in addition to the heart muscle, the musculature that sits on the vascular walls or, for example, the stomach. Neither of these can be actively controlled. And then, of course, the skeletal muscle. We can actively control it and sometimes we overload it. Strains or hyperacidity make us weak.

For sporting performance, but also for everything else our body has to do, we need strength, energy. Our cells generate energy in two different ways. One is through the supply of oxygen. If there is a lack of oxygen, for example because we are out of breath, carbohydrates are one of the sources of energy. This produces lactic acid, lactate. If, as a result of great exertion, the cells become “over-acidified” and the pH value changes, our performance decreases. This can even lead to a drop in performance due to exhaustion. 

Fortunately, we have only rarely felt this on one mountain or another. The hyperacidity, the burning of the muscles, the signal that we have overexerted ourselves can be quite painful. Breaking off and resting was not always possible.  And then there’s the issue of oxygen, our breathing. We take it for granted, but it’s not. It is a miracle. We felt what it means not to get enough oxygen at altitudes above 3000m at the latest. Not only did our performance in terms of physical fitness drop dramatically, we also had to drink in small sips to catch our breath.

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Energy and Gravity

Our bikes weigh 20 kg, our luggage 30 kg, sometimes more, sometimes less, I weigh around 60 kg, Klaus around 75 kg.

So we have to get about 110kg or 125kg of weight moving and keep it moving if we want to make progress.

For a physical consideration of the forces acting during a bicycle trip around the world, we have to look at gravity, friction and their quantitative effects on the system “cyclist and bicycle”.

Gravity and gradients: Gravitational force and work

Gravity is the force that acts on any body with a mass m on the earth’s surface, and it is described by Newton’s law of gravity. Now you’re getting scared, aren’t you?

Let’s say that m = the mass of the body (cyclist + bicycle), and

g is the acceleration due to gravity (which is not the same everywhere on earth, unfortunately we don’t notice that it is less anywhere). The acceleration of free-falling bodies caused by the Earth’s gravity is called acceleration due to gravity, and is usually denoted by g. It is the same for all bodies and is around 9.81 m/s 2. 

When moving a bicycle on flat terrain, the gravitational force is compensated for as a normal force, but as soon as the cyclist climbs an incline, in addition to the forward movement, the component of the gravitational force must be counteracted. All clear? So at least everyone understands that inclines demand much more energy from us, and the heavier we are, the more energy we need.

On steeper inclines, the energy expenditure increases exponentially, as the cyclist, i.e. us, has to do more work to overcome the height.

Unfortunately, we don’t benefit from this when going downhill again. Some people mistakenly think that the extra weight makes us faster. Unfortunately, this is not true.

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You can’t go faster than “falling”

The speed of a falling object increases by 9.81 m/s per second. No matter how heavy the object is. In other words: all bodies fall at the same speed. And we don’t go any faster.

To investigate the law of gravity, Galileo introduced the inclined plane with spheres made of different materials as an experimental set-up. Bodies falling vertically are too difficult to observe. Galileo Galilei was one of the scientists who systematically carried out experiments and separated theory from experiment. 

We also do this every day when we are traveling on inclined planes! hahaha.

He was concerned with the question of whether heavy things fall faster than light ones. With a feather and a stone, this would be clear to see. However, it is not the mass that makes the difference, but the air resistance. The experiment with the two falling objects would be completely different on the moon – without air – as the feather and stone would reach the ground at the same time.

But how can this be demonstrated on earth? That is the art, or rather the will, to experiment or even imagine the air away. This was a very unusual way of thinking at the time, because why would anyone do that? Galileo Galilei stood at the beginning of modern science.

He had two objects of the same size but different weights roll down an inclined plane. As you can’t see which rolls faster, he attached small bells that make a “cling” sound when the ball rolls past – he comes from a family of musicians. If you have two inclined planes with two balls of different weights, you can hear the two “clings” at the same time. If the inclined plane is made steeper and steeper, this leads to free fall.

The law of gravity was developed

“All bodies fall at the same speed.” If we disregard air resistance. So better: “All bodies fall at the same speed in a vacuum”.

Of course, we are less concerned with how fast we fall, how fast we are traveling. For us, it’s mainly about whether we can climb uphill at all. 

Eine einfache Eselsbrücke: 22% Steigung sind auf 100m waagerechter Entfernung 22 Höhenmeter. 

To calculate the gradient of a route as a percentage, you need the height h and the horizontal distance s:

Gradient in % = height / distance s x 100

The result is then the gradient of the distance s as a percentage.
For example, if you have a horizontal section with a length of 100m and a height of 22m, then enter these values into the formula to calculate the gradient: 

Gradient in % = 22/100×100 = 22% 
This gives you the result that the route s has a slope of 22%.

It doesn’t sound like much

And doesn’t look great on paper as an incline. But it is. And you can feel it clearly. A 100% gradient would be an angle of 45 degrees. If you conquer such a total gradient over a few kilometers, this is put into perspective again. 

So we not only have to consider the total gradient on our sections, but also how many kilometers we have to overcome. And of course we also consider small sections with high gradients, because they really wear us out. This is then used to plan our day. If the whole day is uphill, the gradient must not be more than 4-5%. We can manage gradients of 8% over shorter distances. Gradients of 12-14% max. over a distance of 20m. From then on, we have to leave one bike and push the other together.

On gravel, sand or poor road surfaces in general, it becomes even more extreme because the friction increases.

Riding a bike costs energy, even if we are traveling at a constant speed on a flat road

When cycling, there are a number of forces that need to be overcome. 
The road surface condition influences the rolling friction coefficient, as do the frictional resistance, the air resistance and the air pressure in the tires.

The rolling friction coefficient is largely independent of speed. However, the rolling friction coefficient decreases with increasing wheel diameter; large wheels roll more easily than small wheels. And what kind of wheels do we have? Small ones, of course. How stupid.

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And then that damn headwind

With increasing air resistance (headwind), which increases quadratically with speed, the cyclist has to expend exponentially more energy to reach higher speeds. It often feels as if you are not getting anywhere. However, when we’re rolling downhill, this can also be easy on the brake pads.

To summarize once again: from a physical point of view, a bicycle trip around the world is a complex interplay of forces. Gravity and gradients force cyclists to work continuously against the earth’s gravitational pull, then there is air resistance and the various frictional forces, especially rolling resistance, which causes the energy expenditure to vary considerably depending on the ground conditions.

So for our route planning, in addition to the gradients, we also consider the wind direction and strength and the ground conditions (asphalt, hard gravel, sand).

Phew. And I can honestly say that I think we’ve really experienced everything and know what we like and what we don’t like. We like the roads, the smooth asphalt that lets us roll along. With small hills now and then. Our normal speed is around 16km/h. Ideally a little higher. If we cycle for 4-5 hours, we have covered 64-80km. And that’s what we can and want to achieve in a day.

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The Bernoulli effect

Yes, the asphalt roads are nice. But then we might have another problem, especially with the trucks speeding past us: the Bernoulli effect.

https://de.wikipedia.org/wiki/Bernoulli-GleichungIn the 18th century, the Swiss physicist Daniel Bernoulli described an effect that became the decisive basis for modern flying: Flowing liquids and gases exert less pressure on their surroundings than gases at rest. The higher the speed, the lower the pressure.

However, we do not fly, but are attracted to the truck by the negative pressure. A suction is created between us. And I don’t know exactly what that feels like, but I do know that I can no longer control the bike for several seconds and that I’m very close to the truck at the same time. I’m sure everyone has tried the Bernoulli effect at school. Blowing between two sheets of paper or over a sheet: paper is sucked up! Do you remember?

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A sheet of paper

Yes, we are together 7 days a week, 24 hours a day. More or less. And we’ve been together for 2 years and 4 months now. Of course we have our moods and I don’t know what hormones are involved, but I do know that there’s a lot of chemistry involved. And just knowing that helps us not to take everything so seriously. We all have moods. Of course we do. We’re allowed to be. The only thing that doesn’t help is trying to blame the other person for it.

But still, we are who we are and we react. Often perhaps far too emotionally, perhaps wrongly, perhaps for reasons that lie in our childhood.

For example, if I have an idea for an art project (I know, it is not science), even if I might not realize it, but at least want to talk about it, Klaus likes to roll his eyes. If it’s important to me, I’ll start again the next day and then maybe two days later. At some point, he listens and we can talk about it. I just try not to withdraw in a huff, but wait until he can listen and develop the idea with me.

It is a little bit like science

I try not to “hand in” the sheet of paper already completely written, but to leave it white, perhaps with a heading. We develop the rest together. I might then finish it from my point of view, but Klaus was part of it.

Well, and that’s how we manage pretty much everything in our everyday bicycle world tour. Traveling the world by bicycle requires considerable mental strength and adaptability. Studies could investigate how isolation, endurance and unfamiliar situations affect mental health. But I don’t feel like doing that anymore. No more science.

I can say, however, that all these physical laws, biological and chemical relationships that we feel in our bodies every day, sometimes almost make us desperate, but then again full of endorphins to get us through the next stage. Our bodies and their performance capabilities fascinate us every day.

And mentally? I think it’s a kind of mental training and it’s essentially about developing a positive attitude. Focusing on the positive without suppressing the negative. Tasks and challenges need solutions.

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