[paul.fr]

Two questions about how the water in a water balloon would act in zero gravity.

What would happen if an astronaut held out a water balloon and then popped it with a pin?

What would happen if the same astronaut threw a second water balloon at his colleague?

[Don_1]

If you watch an ultra slowmotion film of a water filled balloon being popped in normal Earth gravity, you will see the water retains it's shape for a spilt second. In zero gravity I should think apart from the disturbance caused by the balloon rubber returning to it's unstressed size, the water should retain it's shape.

[Bikerman]

In zero g then the water will act to form a sphere (minimum surface area per volume). The balloon will simply reinforce this behaviour....

[lyner]

One large sphere would be very unstable* but, in a big enough container (removing local gravity effects) with perfectly still air surrounding it, it would stay spherical.
In orbit (microgravity) the shape would be slightly ellipsoidal (prolate / 'egg' shape) with the long axis pointing  towards the centre of Earth.

*There are many Utube Movies which show this sort of thing. C4 yourself.

[Outcast]

Good question.
The hydrazine that is the propellent for small thrusters on communication satellites is stored in spherical tanks. It forms a bubble in the center of the tank due to the surface tension of the hydrogen in hydrazine, similar to water. The question that arises is how to get the hydrazine to flow out of the tank as the supply is depleted to a progressively smaller bubble. The answer is a fixed blade extending to the center of the tank that breaks the surface tension of the bubble and allows it to flow along the blade (the specific design of the blade is proprietary.)

[chiralSPO]

[Bored chemist]

That's an interesting video.
If you spend 3 minutes in free fall (near the Earth) how fast do you end up travelling?
How far do you fall?

[chiralSPO]

This flight was going up and down repeatedly. Alternating between near-free fall and increased acceleration away from the ground. You can see the periodic transitions in the video.