Science
Rules!
CONCEPT SUMMARY: The density of water, ice, and snow aren't the same even though all three are composed of H
2
O. In this experiment we'll measure the relative densities of these three substances. After you're done you can your results to standard ratios from accepted snow-to-water ratios!
1. JUST THE FACTS
Snowflakes are formed by the freezing of water vapor in the air. Layers of snowflakes on a surface, such as the ground, are simply called snow. Snow is mostly a combination of snowflakes and air. The amount of air that snow contains affects its volume (the amount of space it takes up). When snow melts, the trapped air is released. Thus, the volume of snow is greater than the volume of the liquid water it forms when melted. Not all snow is the same, and snow is not the only form of frozen water. Ice, sleet, and hail are also mostly a combination of frozen water and air. Let's compare the properties of ice and snow from your area to other known values.
Note: if a non-metric measuring cup is used for this activity, fluid ounces can be converted to milliliters using this relationship: 1 fluid ounce = 30 mL (strictly speaking, 1 fluid ounce = 29.57 mL). Whole number estimates of other relationships between metric and English measurements are also used, such as 1 quart = 1 liter, so 1 cup = 250 mL.
2. WHAT'S UP?
How does the volume of snow compare to the volume of liquid water that the melted snow forms?
3. WHAT DO YOU THINK?
Make a guess about the amount of water you think a cup of snow will form when melted. Half as much? One-third as much? How much?
4. STUFF

 pencil ruler
 1 sheet of paper
 permanent marker
 three (3) 10-oz (~300ml) clear plastic drinking cups (We suggest using 10 oz. clear plastic picnic cups that come from the same package, although other size cups will work. You need three because we will be finding average values)
 tap water

 volume measuring device ( graduated cylinder or metric measuring cup 750 ml
(3 cups) snow (use shaved ice, crushed ice or accumulation of frost from a home freezer as alternatives if snow is not available.)
 spoon
5. JUST DO IT
1.
Use the pencil and ruler to prepare a data table on the paper similar to the one in
Scoreboard below.
2.
Near the bottom edge of each cup, use the pen to label the cups A, B, and C.
3.
Put 250ml (1 cup) of unpacked snow into each cup. Use the spoon to help remove the snow from the cup, but take care not to press the snow flakes together.
4.
Record the volume of the snow, which should equal 250ml (1 cup), where you found it (your town, city, or locale), and a description of the snow (i.e. 3 day old snow) in the data table.
5.
Draw a line and mark the snow level with an S (for snow) on each cup (all 3 should be the same).
6.
Set the cups on a table indoors and allow the snow to melt.
7.
When all of the snow has melted mark the water level on all three cups SWE (for snow water equivelent).
8.
Pour the water from cup A into your measuring device. Record the volume of the water in the data table.
9.
Determine the ratio between the volume of the snow and the volume of the water.
Do this by writing a fraction with water volume as the denominator and snow volume as the numerator (ratio = Volume Snow/VolumeWater). Express the answer as a decimal by dividing the denominator into the numerator. Record the answer. (Note: the answer tells you how many time greater the snow volume is than the volume of the melted water it forms.)
10.
Repeat steps 6,7 & 8 for cups B & C.
11.
Determine the average ratio and record. Do this by adding the ratios and dividing by 3.
6. SNOW-WATER DATA
Create a table like the one below and record your data.

SNOW / WATER DATA TABLE-1
Snow Sample Location
Description
SAMPLE VOLUME (ml) RATIO snow water Snow:water
A
B
C
Average Volume ratio snow/water =
Now, compare your results to Table 2 provides accepted snow categories and their average snow/water ratios. Table 3 illustrates the distribution of these categories of snow over the 2003 winter season in Quebec, Canada.
Snow category
Very heavy
Heavy
Average
Light
Very light
Ultra light
Average ratio
4:1
7:1
10:1
15:1
20:1
25:1
Table 2: Proposed snow categories with their associated snow/water ratio values.

Snow category
Snow/water ratio
Early/late in season
Heavy
5.6-8.5:1
3%
Average
8.6-12.5:1
70%
Light
20%
12.6-17.5:1
Very light
17.6-22.5:1
6%
Ultra light
≥
( NOV/MAR-
APR )
Mid-winter
( DEC-JAN-
1% 48% 37% 11%
FEB )
Table 3: Distribution of snow categories for the 490 cases included in the climatological study. Data is split between 2 periods over the 2003 winter season (Quebec, Canada).
Original Source: http://astro.uchicago.edu/cara/southpole.edu/flaky.html
22.6:1
1%
3%