Snowflakes.

A journal for students to record learning about the three states of matter and both word and diagram descriptions can be downloaded here , or viewed in the graphics at the bottom of this page. Some additional information about snowflakes follows:

SNOWFLAKES can show us why ice floats in water.
Like six- sided honeycombs made of wax by bees to store honey, solid water freezes into a hexagonal crystal lattice.
Because this crystal lattice, held in place by polar covalent water molecules whose hydrogen atoms are connected by "hydrogen bonds" to oxygen atoms in nearby molecules, is stable in this particular six- sided shape, ice is less dense than water. To explain it in a slightly different way, solid ice has water molecules locked into an arrangement that has "holes" in it, which are not found between molecules of liquid water. The highly flexible hydrogen bonds between water molecules do not hold the faster liquid molecules as consistently as they are held in colder, solid water. Liquid water molecules push by each other, repelling and attracting each other, but also moving quickly enough to allow the spacing between molecules to vary within a range which results in a substance that is more dense than solid ice.
Snowflake formation depends on humidity and temperature in clouds. Water VAPOR, not liquid, condenses directly from its active vapor state into solid snow crystals without ever becoming a flowing liquid during snowflake formation. To say it differently, bazillions of the tiniest little fast moving water molecules, close together in a cold cloud, will cling together in symmetric/ balanced pattern in the air until they become large enough to fall as solid snow.
slg water molecules.jpg spiky flake.jpg
snow to liquid.jpg
addition of heat energy results in crystal snowflakes becoming less ordered (higher entropy) - AND - in general, the water molecules in the liquid are closer together than they are in the solid crystal form


"Libbrecht’s morphology diagram below illustrates that ice crystal shape is a factor of both humidity and temperature. Temperature is the most important factor, and plates tend to form in the 0°C to -3°C and -10°C to -22°C ranges (red), while columns tend to form from -3°C to -10°C and below -22°C (green). Lower humidity tends to form simpler crystal shapes, while higher humidity tends to form more intricate crystals. It is currently not known why ice crystals form different shapes at different temperatures, as the physics of how the water molecules bond to a growing ice crystal are very complex and not well understood (Libbrecht)."- quote taken from......http://is-masaru-emoto-for-real.com/

libbrecht humidity temp snowflakes.jpg
image taken from http://is-masaru-emoto-for-real.com



A research- based approach to HSSCEs on the topic of states of matter, changes in state, and word and diagram representations of molecules in each state follows in the student journal below.


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pages 1 and 2 of the student journal

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snowflake journal pages 3 and 4.jpg
pages 3 and 4 of the student journal

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snowflake journal pages 5 and 6.jpg
pages 5 and 6 of the student journal

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snowflake journal pages 7 and 8.jpg
pages 7 and 8 of the student journal



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