Question

If you make water particles absolutely still will they become a solid? and would their temperature change? Thank you!

Answer 1

The temperature would be `-273.15^oC` and the water would be a solid but not exactly.

Explanation:

The movement of the water particles is a sign of kinetic energy. The average kinetic energy of a system is what we call the temperature. When the particles completely and absolutely stop moving, this decreases the temperature and the particles reach absolute zero. At absolute zero, there is no kinetic energy or movement of particles and the system of particles should become a perfect solid (keyword: should).

However, as you approach this point of energy (or more accurately the lack thereof), physics slowly bends to the will of quantum mechanics which I am nowhere near qualified to explain to you. Here is a link that could help you understand what absolute zero is and if you're really interested in the effects of it, there are plenty of rabbit holes to jump into on the internet filled with studies and observations.
https://www.newscientist.com/article/dn18541-what-happens-at-absolute-zero/
I hope this was somewhat helpful!!!