How Ice Is Made
To put it plainly, ice is made when liquid water is cooled to a temperature that is below 0 degress celcius.
It can be formed in a variety of different ways. But looking at the basics of how solids and liquids work, let’s start from the beginning. Molecules in a solid contain small amounts of energy and its structure is held together because of this low amount of energy. However, when you increase the temperature, the energy is also increased, which allows the molecules to vibrate against each other more.
Increasingly adding more and more heat/energy allows the molecules to move around more until they are able to break free and become liquid.
In order for the reverse to happen, you would need to take heat/energy away. The process of removing heat is called cooling. The bonds between the molecules must be allowed to form, which will then create the solid (which in this case is ice!).