# Simventure how to win

## This is how you win the snowball fight

© Provided by Der Bund How do you win a snowball fight? Physically sound knowledge can provide advantages.

Physics professor Metin Tolan explains what you need to consider when building and throwing the perfect snowball.

© Provided by Der Bund How do you win a snowball fight? Physically sound knowledge can provide advantages.

Mr. Tolan, can physics even help us in a snowball fight, and if so, how?

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a, she can. On the one hand it is about the nature of the snowball itself - and on the other hand it is about the throwing technique.

The snowball shouldn't be too heavy, you know that from the shot put

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en. You don't throw very far because the gravitational force is too strong. But it mustn't be too easy either. Everyone who has tried to throw a table tennis ball knows this. The problem here is air resistance. Namely, it provides the frictional force. The gravitational force must therefore not be too great

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but it always has to be much bigger

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he be considered the frictional force! And that's most likely to be the case with a medium-weight snowball. To get this weight, or the right mass and density of the snowball (mass = density x volume), it is important that you have a little water in the snow. It's worse with powder snow than with damp, sticky snow, of course. It doesn't stick together and it's too light. Slush that has been lying around for a few days is actually ideal for snowballs. But unfortunately that's such a mess.

© Graphic: Daniela Rudolf after Prof. Dr. Metin Tolan (Jetzt.de) This graphic shows the trajectory of the ball, determined by altitude and flight range at each point in time of the flight. v describes the throwing speed and a the throwing angle. In addition, you can see the gravitational force acting perpendicularly on the ball and the frictional force, which always acts parallel and opposite to the current direction of movement. Without air resistance, i.e. without friction, the ball would fly in a completely symmetrical trajectory parabola.

What should you watch out for in the shape of the snowball? Is the goal a perfectly round ball?

The shape has very little influence. In and of itself, of course, a streamlined teardrop shape is best. This has to do with the aerodynamic drag, which is reduced as a result - just like with a racing car, for example. But you would have to be able to throw the ball exactly in the direction of the drop, i.e. with the tip first. And even then the effect would be so small that it would be measured in an experimental situation but would not be noticed in a snowball fight.

So you can optimize the snowball to a certain extent. And then?

Then of course it depends on the litter. A snowball fight is, on the one hand, about throwing as precisely as possible in order to hit the target person. On the other hand, it is about throwing as far as possible in order to be able to hit the target from a distance that they cannot overcome with their balls. In both cases, a high discharge speed is important. This makes the beginning of the trajectory parabola more of a straight line, which extends the range and makes it more precise. The reason for this is that gravity cannot strike as strongly and the scatter is less. Even if your target isn't that far from you, you should throw with as much force as possible. A slower throw in a bigger one

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his bow makes it close to the other

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In addition to the discharge speed, is there any other variable that has to be taken into account?

Yes, the throwing angle. These two parameters are important for every throw. When it comes to hitting a target, you have to, as just said, the spread by a large

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Minimize the speed possible. But when it comes to throwing as far as possible, many believe that an angle of 45 degrees is optimal. That would also be true if one intended to throw something on the moon. On earth, however, air friction must be taken into account. Depending on the properties of the projectile, the result is an optimal throwing angle of around 40 degrees. A big

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er angle only allows the snowball to fly higher, but not further. At a smaller angle, it hits the ground too quickly.

© Graphic: Daniela Rudolf after Prof. Dr. Metin Tolan (Jetzt.de) This is the optimal shooting angle for a snowball. This graphic and the corresponding formula show the optimal firing angle. This depends on the parameter E, which is calculated from air resistance (ß x v) and gravity (m x g). The optimal value of E is 1. This means that the angle that leads to the result E = 1 in this formula results in the greatest possible throwing distance with the same throwing speed.

When it comes to air resistance, does the wind also play a role?

The snowball should usually be so heavy that the wind is not very strong

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has influence. If there is a real storm now, it is of course better to position yourself with a tailwind.

Last question that arises: When was your last snowball fight, Professor Tolan?

Oh, that was a long time ago. I'm a physicist, I don't like going out.