Hello, I am ESA astronaut Matthias Maurer
and I am currently on the International Space Station ISS at an altitude of 400 km,
fully in weightlessness as you can see.
And here we are on the International Space Station,
because we perform experiments in weightlessness.
I would like to demonstrate the interesting effects
of all this using the example of water.
I brought this bag of water
and then you can perfectly see
how water forms a sphere in weightlessness.
Now we can see, how this sphere is drifting away.
This is because we have an air flow here.
I will try to capture it again.
We also see this sphere very nicely here,
that water has a certain surface tension.
I can see that this sphere is not a perfect sphere,
but that it vibrates and oscillates a bit
and that has something to do with resonance.
We could create a perfect sphere here if it were at rest.
Because of the air flow this sphere is pushed back and forth over and over again
also when I set them in vibration.
Then this sphere oscillates and the forms of oscillation
that we see here depend on the viscosity.
So if I have a different fluid, which is stiffer, i.e. more viscous,
then this liquid also vibrates differently and we use this effect,
to melt metals and learn how viscous
this metal actually is at a certain temperature.
Now, I try to make the whole thing a little bit bigger.
We also see the water droplets here, they fly apart at some point.
They are perfect marbles, the others are floating away right now.
Okay, now I need to be a little slower here.
There goes another satellite.
And this bat looks a bit like a table tennis bat,
which is actually a hydrophobic surface.
So I would have expected the sphere to stick out perfectly here,
but the effect doesn't seem to work and the coverage is optimal here.
That means I have a very, very flat layer of water.
Now let's see how much we can pump in there before it falls apart.
We can see that the liquid is resting on the surface and swings back and forth, so to speak.
Now I'll take a toothbrush.
A toothbrush, a very normal toothbrush, fresh out of the package.
It can be easily wet by water.
I can show it like this.
The water really sizzles between the fibers.
I can also build a bridge here, where I pull out the water
and then at some point this bridge breaks.
And here no sphere is formed, but the water
goes in between these different fibers,
in the brush and wets it perfectly.
These oscillations look very beautiful.
Let's try to control this sphere a bit more.
A few droplets fly around here, but that's not a big problem.
Let's see if we can make this sphere grow a little bit more.
We see here that we have a very, very strong ventilation system in the Columbus module.
This is necessary to ensure that I always have enough oxygen to breathe.
Here, we can also see the lens effect very well.