Snow and hail is a solid, sleet has solids within a liquid mass, and rain is liquid. Snow is water that crystallizes when the temperature gets below freezing. Sleet is when the temperature freezes, but then as it falls from the clouds it partially melts.

The particles are held rigidly in place by all the other particles around them so they can’t slip past one another or move apart. This gives solids a fixed shape and a fixed volume.

For those of us interested in the water cycle, sublimation is most often used to describe the process of snow and ice changing into water vapor in the air without first melting into water. The opposite of sublimation is “deposition”, where water vapor changes directly into ice—such a snowflakes and frost.

Are all snowflakes unique? The short answer is, yes, because each ice crystal has a unique path to the ground. They will float through different clouds of different temperatures and different levels of moisture, which means the ice crystal will grow in a unique way.

Though snowflakes are beautifully varied, there is one underlying pattern that is seldom broken: snowflakes’ intricate patterns (almost) always have six sides. The reason why, says science blogger Megan Nantel, is because snowflakes are made of water, and water molecules bonded together take on particular shapes.

Even though all snowflakes have six sides or points, no two look exactly alike. Shape and size depend upon the temperature and amount of moisture in the air. The more solid patterns form slowly in clouds high above the earth where there is less moisture and the temperatures are colder.

The ice crystals that make up snowflakes are symmetrical (or patterned) because they reflect the internal order of the crystal’s water molecules as they arrange themselves in predetermined spaces (known as “crystallization”) to form a six-sided snowflake.

Temperature and the amount of moisture in the air determine a snowflake’s basic shape. Scientists describe those shapes using names such as columns, needles, plates and dendrites.

At just below freezing temperature (0 C) a snowflake might look like a tiny plate, while a few degrees colder sees snowflakes that are shaped like columns or needles. The classic star-shaped snowflake makes an appearance around -15 Celsius. Whatever the shape though, snowflakes usually have six sides.

Snow crystals can be plates. Plate crystals are thin like star crystals, but they don’t have arms. The simplest kind of plate is a hexagon with six straight sides.

Dendrite means “tree-like”, which describes the multi-branched appearance of these snow crystals. Stellar dendrites have six symmetrical main branches and a large number of randomly placed sidebranches.

The snowflake can be a symbol of rebirth. Snow makes the earth look clean and fresh. This is why snowflakes can also be a symbol of purity. When it melts, it’s transformed into water, making it a suitable symbol for transformation and new beginnings.

Snow crystals are sensitive to temperature and will change in shape and design as they fall from the cloud and are exposed to fluctuating temperatures. To have two snow crystals or flakes with the same history of development is virtually impossible. High-resolution images show snowflake complexity.

Researchers do know enough to confirm that the “no two snowflakes are alike” adage is likely true for fully developed snowflakes, Nelson added. But it may not hold for some flakes that fall out in the early stages of crystal formation, he said.

Now, it’s not a law of nature that no two snowflakes could be truly identical. So, on a very technical level, it’s possible for two snowflakes to be identical. And it’s entirely possible that two snowflakes have been visibly indistinguishable. But probability dictates that this is incredibly unlikely.

Bentley

They link up in a strict pattern known as six-fold symmetry (that’s why we tend to associate snowflakes with hexagons or six-pointed stars) which gives us the basic snowflake template. That shape changes even further as they fall through the air. Snowflakes beneath the microscope show how different each one is.

white

The most basic definition of black ice is a thin coat of highly transparent ice. The reason it is transparent is because it blends in with road pavements since it is so thin, making it nearly impossible to see. It’s called black ice since it looks black, like the color of the road pavement it forms on.

Chris O’Brien, a meteorologist at the US National Weather Service, told Time magazine that the discoloration is caused by dust particles carried on strong winds all the way from Texas. Satellite images show large plumes of dust drifting northwards from the US-Mexico border.

Pure water and color The water you see every day contains dissolved minerals and often suspended materials. The water is in fact not colorless; even pure water is not colorless, but has a slight blue tint to it, best seen when looking through a long column of water.