SCIENCE

• Snowflakes are six-sided! Dendritic snowflakes (more ornate snowflakes) form when the air temperature is between 10°F and 3°F (-12°C to -16°C) [refer to air temperature versus ice crystal shape, courtesy USA TODAY Weather, or the Make Snow Java applet (reset by clicking below cloud)]. So, where is it cold enough for dendritic snowflakes to form? High in the atmosphere (usually air temperature decreases with increasing altitude). Access the latest Upper Air Text Data for Selected Cities in the US. [Note: IAD = Dulles, VA. Upper air temperatures are reported in degrees Celsius; convert Celsius temperatures to Fahrenheit using the Weather Calculator, courtesy Sterling, VA NWS Forecast Office).]
• Did you know that most precipitation (including rain) starts as snow? See how the three-dimensional structure of the atmosphere determines the type of precipitation that reaches the Earth's surface: How winter storms bring rain, ice and snow, courtesy USA TODAY Weather. Experiment with the Precipitation Type Java applet.
• Estimate the fall speed of snowflakes. Watch snowflakes as they fall past an object of known height, e.g., a building. Speed = Distance/Time. If a building is made of 2.75" thick bricks with 1/2" of mortar between rows of bricks, then every 10 rows of bricks equals approximately three feet (32.5" to be exact). On average, snowflakes fall at a speed of approximately 3 feet per second, or 10 rows of bricks every second. [Idea courtesy Marcia Politovich, Atmospheric Scientist, National Center for Atmospheric Research, Boulder, CO.] Activity Extension: Calculate how long it takes snowflakes to fall to the ground from cloud base.
• Capture snowflakes on chilled glass microscope slides; preserve using artist's spray fixative (e.g., Krylon® "Crystal Clear"). Use a low-power binocular microscope to examine preserved specimens. Unless the air at the Earth's surface is very cold and dry, most snowflakes will be partially melted.
• Make a rain/snow gauge. Cut off the top of a clear plastic two-liter soda bottle. Use a permanent marker to mark the outside of the bottle in centimeters or inches (measuring from bottom-to-top). Put the bottle outside in a place where it can collect falling snow. Measure and record the depth of snow in the container. Let the snow melt, then measure and record the depth of water in the container. Determine the snow/water ratio. [A typical ratio is 10:1, i.e., 10 inches of snow is equivalent to one (1) inch of liquid precipitation. In theory, the snow/water ratio should be higher when the air temperature is colder, and lower when the temperature is closer to the freezing point.] Activity Extension: Fill a plastic 12- or 20-fl. oz. soda bottle with water to the point of overflow; tightly cap bottle and place outside (if air temperature is below freezing) or in a refrigerator freezer. Observe that the bottle bursts when the water freezes. Relate this observation to snow/water ratio. Caution: DO NOT use a glass bottle!
• Research the chemistry & physics of ice crystals. A good starting point: USA TODAY Weather's Resources: Winter weather. See also, SnowCrystals.com, created by Kenneth G. Libbrecht, Professor of Physics at Caltech. Dr. Libbrecht is the co-author of a wonderful new book entitled, The Snowflake - Winter's Secret Beauty. (Middle- or High School)
• Explore the mysterious beauty of ice crystal atmospheric optical phenomena by visiting the Atmospheric Halos Web site; look at the real sky for sundogs (or parhelia), halos, and Sun pillars.
• Study the science of winter weather:
  • Types of Winter Storms
  • How Winter Storms Form
  • Wintertime Forecasting
  • Winter Weather Safety
  • Winter Precipitation
  • National Weather Service: Winter Weather Awareness
  • NOAA NCDC CLIMVIS (Climate Visualizer) - Graphically display relevant weather parameters such as temperature (maximum or minimum), precipitation, snow depth, etc.
  • National Severe Storms Laboratory

TECHNOLOGY

• Computer-Aided Design (CAD) of snowflakes using either Snowflake Designer or Make-a-Flake (requires Shockwave Player multimedia plug-in for your Web browser):
  1. Design virtual snowflakes before actually making paper snowflakes (refer to ARTS & CRAFTS for directions re: folding & cutting paper snowflakes). This is so cool!
  2. Challenge students to duplicate a specific snowflake pattern, e.g., Wilson Bentley's snowflake photomicrographs or Snow Crystal Photographs (a collection of works from various scientists/artists). Test patterns using either Snowflake Designer or Make-a-Flake.
• Using a Spreadsheet to Organize Data and Make a Graph of Average Snowfall in Washington, D.C., a classroom-ready activity by Joanne Goodwin, School-Based Technology Specialist (SBTS), Churchill Road ES, FCPS. Activity may be adapted for other locations by referring to a NOAA/NCDC table of Snowfall - Average Total In Inches, annually by month. [Note: T = Trace, or less than 0.1 inch.]

MATHEMATICS

• Primary Grades: Explore snowflake symmetry. Print & photocopy a variety of snowflake photographs; challenge students to fold snowflakes along lines of symmetry. (Grade Level 3, FCPS Program of Studies)
• The geometry of snowflakes--snowflakes are six-sided hexagons: (Grade Level 5, FCPS POS)
  1. On an 8 1/2" x 11" sheet of white paper, use a drawing compass (such as the Safe-T Compass) to draw a circle 6" in diameter that is perfectly centered on the page (to find the exact center of the page, lightly sketch an "X" from corner-to-corner).
  2. From the center point of the circle, use a protractor to divide the circle into six equal slices (of pie); draw six triangles (360/6 = 60 degrees).
  3. Fold the circle in half, forming a semi-circle with three 60-degree angles (180/3 = 60 degrees); fold paper into thirds (along lines between pie slices). Now students should understand how you fold paper to make six-sided snowflakes!
• Probability - Discuss probability (for background information, visit Probability Central). Access a map of the United States showing the Probability of a White Christmas (1" of snow or more) to determine the probability of a white Christmas for your location. The NCDC map shows that the chance of a white Christmas in the nation's capital is slightly more than 10%! Play song, White Christmas by Irving Berlin (Bing Crosby's rendition is a classic!).
• Word problems - Take the chill off a cold morning with these challenging warm-up problems:
  1. If a typical snowflake falls at a rate of descent of less than 5 feet per second, then how long would it take for the snowflake to reach the ground from a cloud base of 10,000 feet (the approximate height of a typical nimbostratus cloud base)? Answer: 10,000 feet / 5 feet per second = 2,000 seconds or approximately 33 minutes!
  2. On average, Washington, D.C. receives 39.51" of precipitation annually, including 18.3" of snow. If we assume that 1 inch of liquid precipitation equals approximately 10 inches of snow, then what percentage of the total annual precipitation in Washington, D.C. falls as snow? Answer: 39.51" / 1.83" (water equivalent of average annual snowfall) x 100 = approximately 5%

LANGUAGE ARTS

• Read The Snowflake Man, an article by Duncan C. Blanchard (Bob Ryan's 1999 Almanac and Guide for the Weatherwise). Answer the following mini-scavenger hunt questions:
  1. Who was "the Snowflake Man?"
  2. Snow crystals are symmetrical with how many sides?
  3. What is the well-known expression about snowflakes coined by the Snowflake Man (after photographing thousands of snowflakes)?
• Read the 1999 Caldecott Award winning book, Snowflake Bentley, by Jacqueline Briggs Martin, illustrated by Mary Azarian. (Ages 4-8. Recommended as a read-aloud for Grades 1-3; read-alone Grades 4-5.)
• Read Caldecott Medal winner The BIG SNOW, by Berta and Elmer Hader (recommended as a read-aloud for Grade 2) or The Mitten, adapted and illustrated by Jan Brett (K-3).
• Write "snow" diamante poems. Diamantes are diamond-shaped poems with seven (7) lines. Incorporates oral, analytical thinking, reading, and writing skills. Great exercise for parts of speech. Mount student poems on diamond-shaped colored paper; arrange six diamante poems into a giant snowflake for bulletin board display. For background information and sample diamantes, visit the following Web sites:
  1. PIZZAZ!...DIAMANTE POEMS
  2. Create a Diamante
• Write (and illustrate) "snow" poems or short stories.
• Read Snow Crystals, by Wilson Bentley & W. J. Humphreys, a collection of 2,453 of Bentley's best snowflake photographs (the larger cover image displays numerous snowflakes to duplicate).

ARTS & CRAFTS

• How to fold & cut snowflakes using an 8 1/2" x 11" sheet of paper and scissors [directions courtesy Joanne Goodwin, School-Based Technology Specialist (SBTS), Churchill Road ES, FCPS].
• How to fold & cut snowflakes using a square sheet of paper:
  1. Maddy & Maverick's Paper Snowflakes Web site
  2. Ben & Jerry's Paper SnowFlakes - Simple fold-&-cut paper snowflake templates. Use SnowFlake #3 only. [Editorial Commentary: While fun to make, the Ben & Jerry's "#1- & #2 Cone Flake" templates are four-fold designs that produce eight-sided snowflakes. Don't teach Bad Science--snowflakes are six-sided!]
• Transform your classroom into a winter wonderland! Use thread (or fishing line) to hang paper snowflakes from the ceiling; use transparent tape to hang them on windows.
• Illustrate snow poems or short stories, e.g., wintery skyscapes or snowy landscapes such as the Impressionists in Winter: Effets de Neige virtual exhibit.
• Take snow photographs (digital, Polaroid, or conventional film). Single-use cameras are inexpensive (typically priced around $10 each) and can be loaned to students for use when school is closed due to inclement weather. Panorama (wide-angle) single-use cameras are great fun! Simple writing exercise: write captions that clearly and concisely describe the photographs. Use a sequence of photographs to tell a story (like a movie storyboard). For tips from the pros, see two resources from Kodak: Winter Photo Tips; and Winter Photography - Better Pictures in the Snow.

SOCIAL STUDIES/GEOGRAPHY

• Access a current National Radar Summary map showing areas of precipitation across the United States, courtesy WSI Corporation. Use two-letter abbreviations to list all of the states (if any) in which frozen precipitation is currently falling, including mixed precipitation (sleet and freezing rain) and snow.
• Refer to a current NOAA/NESDIS satellite-derived U.S. snow cover map. Use two-letter abbreviations to list all of the states (if any) in which snow covers the ground.
• Access current NOAA/NWS National Snow Analyses maps of the United States. Expressed as a percentage of the total area of the United States, what is the area covered by snow? What is the average snow depth? What is the maximum depth?
• Where is the "snow belt" in the United States?
• Lake Effect Snow:
  1. Warm waters of Great Lakes breed snowstorms, including cool animated graphic from USA TODAY Weather.
  2. Lake Effect Snow - Why In Syracuse?
• Based upon a table of average annual snowfall (or maps of U.S. Snowfall Patterns), select at least three possible United States venues for the Winter Olympics (e.g., Salt Lake City, Utah, 2002). Hint: Since numerous Olympic events involve sliding downhill on snow, you should consider cities located in the mountains!

HEALTH & PHYSICAL EDUCATION

• Winter Weather Safety:
  1. NOAA/NWS: Winter Storms - The Deceptive Killers
  2. The Weather Channel: Project SafeSide
  3. American Red Cross: Winter Storm Safety
  4. FEMA/Talking About Disasters - Providing Safety Information to the Public: Winter Storms
• P.E. In The Snow

MUSIC

Use a computer to play "mood" music while students work. Click [Play] to spawn an external audio control panel:
• [Play] Let It Snow
• [Play] Winter Wonderland
• [Play] Frosty the Snowman
• [Play] White Christmas

FUN & GAMES

• Make sno-cones. Yum!
• Make snow angels!
• Build a Snowman (Java)
• Online Winter Games