A fun fact from NGKids :
“Bet You Didn’t Know: Twenty inches of snow equals one inch of water on average.”
Try it! Put some snow in a clear container and measure how deep it is. Then, allow it to melt. Measure how deep the remaining water is.
You can figure out whether your results were consistent with the NG Kids fact (10 inches of snow* should melt down to around 1/2 inch of water or 50cm of snow* should melt down to 2.5cm.) The amount of air in snow affects its volume (or how much space it takes up). When snow melts, the trapped air is released. This is why the volume of snow is greater than the volume of the liquid water it forms when it melts. If the snow isn’t perfectly fresh, this experiment may have the added benefit of reminding you why you shouldn’t eat snow.
The amount of water in snow can vary quite a bit, depending on the size and shape of the snow crystals and how much air they contain.
*I’m guessing that NG Kids was referring to unpacked snow. Our kids packed the snow into containers and we go more water than we expected. Ask your kids why they think packed snow melts to give you more water than unpacked snow.