Freshly Baked Science
How to: Make The Perfect Snowball (According to Physics)
19th December 2018
You all know what we’re talking about when we say that there is good snowball snow and bad snowball snow! There is a very fine line between throwing snow dust at somebody and a round block of ice. The ideal snowball snow is somewhere in between these two, where it keeps its integrity while it hurtles through the air and breaks into a snowstorm on impact. So, why is it that some snow makes perfect snowballs, and some doesn’t?
The simple answer to this question is physics. In a liquid state, water takes up less space than in its solid state. This is due to the hydrogen bonds that form while water is liquid. The force of attraction created by the hydrogen bonds means that liquid water can be packed more densely than solid water.
Under high pressure, frozen water will melt and once the pressure is released, it refreezes. This acts as a binding agent to hold the snow together and create a solid ball. So, remember that when you’re making your snowballs, it’s all about the pressure of your hands, not the heat!
If the weather gets too cold, the snow becomes that powdery nonsense that doesn’t hold any shape and just sticks to your gloves. The snow at this temperature is too cold to allow the pressure of your hands to melt the snow, so it doesn’t weld together. In these conditions, if you are still desperate for a snowball fight, try sourcing your snow from warmer areas like near buildings and cars!
If the weather is too warm, the snow becomes too melted and slushy. When you try to compact this kind of snow together, it doesn’t take much pressure to melt and refreeze the water. This creates solid balls of ice that are simply too cruel to throw at people (definitely wouldn’t recommend, as people tend to retaliate).
The best snow is the kind that falls when the temperature is just below freezing (the kind that clumps together while it falls). This snow will compact into perfect snowballs with the firm pressure of your hands but won’t be ice balls. There is no greater feeling than creating the perfect snowball and watching the burst when it hits your target… satisfaction overload!
Are you planning on having snowball fights this winter? Let us know your sneaky tactics via email (firstname.lastname@example.org) or via social media (@wonkscience) with the hashtag #STEMintoChristmas!