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2006-06-14 20:18:54 · 8 answers · asked by Anonymous in Education & Reference Homework Help

8 answers

i assume physical change means going from one state to another like solid to liquid to gas.

If that is so, then the formation of snow is a state change of H2O from liquid state to a solid state.

2006-06-14 20:23:49 · answer #1 · answered by julius 4 · 4 0

The Formation Of Snow

2017-01-13 03:33:21 · answer #2 · answered by ? 4 · 0 0

Snow is precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes. Since it is composed of small rough particles it is a granular material. It has an open and therefore soft structure, unless packed by external pressure.

Snow is commonly formed when water vapor undergoes deposition high in the atmosphere at a temperature of less than 0°C, and then falls to the ground.

The probability of snowfall varies with season, location, and other geographic factors such as latitude and elevation. In the latitudinal area closer to the equator, there is a rather small chance of snowfall, 35° N and 40°S are often quoted as a rough delimiter. The western coasts of the major continents remain devoid of snow to much higher latitudes.

A snowflake always has six lines of symmetry, which arises from the hexagonal crystal structure of ordinary ice (known as ice Ih) along its 'basal' plane.

There are, broadly, two possible explanations for the symmetry of snowflakes. Firstly, there could be communication or information transfer between the arms, such that growth in each arm affects the growth in each other arm. Surface tension or phonons are among the ways that such communication could occur. The other explanation, which appears to be the prevalent view, is that the arms of a snowflake grow independently in an environment that is believed to be rapidly varying in temperature, humidity and other atmospherical conditions. This environment is believed to be relatively spatially homogeneous on the scale of a single flake, leading to the arms growing to a high level of visual similarity by responding in identical ways to identical conditions, much in the same way that unrelated trees respond to environmental changes by growing near-identical sets of tree rings. The difference in the environment in scales larger than a snowflake leads to the observed lack of correlation between the shapes of different snowflakes.

However, the concept that no two snowflakes are alike is not necessarily true. Strictly speaking, it is extremely unlikely for any two objects in the universe to contain an identical molecular structure; but, there are, nonetheless, no known scientific laws which prevent it. In a more pragmatic sense, it's more likely, albeit not much more, that a pair of snowflakes are visually identical if their environments were similar enough, either because they grew very near one another, or simply by chance. The American Meteorological Society has reported that matching snow crystals were discovered by Nancy Knight of the National Center for Atmospheric Research. The crystals were not flakes in the usual sense but rather hollow hexagonal prisms.

2006-06-14 20:24:13 · answer #3 · answered by Drewy-D 4 · 0 0

snow, precipitation formed by the sublimation of water vapor into solid crystals at temperatures below freezing. Sublimation resulting in the formation of snow takes place about a dust particle, as in the formation of raindrops. Snowflakes form symmetrical (hexagonal) crystals, sometimes matted together if they descend through air warmer than that of the cloud in which they originated. Apparently, no two snow crystals are alike; they differ from each other in size, lacy structure, and surface markings. Snowfall, reduced to its liquid equivalent, is usually included in statistics on rainfall; the factors determining snowfall are similar to those affecting rainfall. On an average, 10 in. (25 cm) of snow is equivalent to 1 in. (2.5 cm) of rain. In the United States the average snowfall is about 28 in. (71 cm) per winter; the record is 1,140 in. (2,896 cm) at Mt. Baker in Washington state during the snow season of 1998–99. Snow that piles up on slopes may suddenly slide downward in an avalanche. A glacier consists of ice that was formed from compacted snow. Snow serves as an insulating blanket, lessening to some extent the extremes of temperature fluctuation to which the soil is subjected, but it also brings about a rapid cooling of the overlying atmosphere, giving rise to polar air masses. Snow lessens loss of water by dormant plants. The sudden melting of snow is a primary cause of floods. Snow necessitates the building of snowsheds over rail lines and highways in certain mountain localities where a heavy fall is likely to impede travel; the use of snowplows to clear sidewalks, streets, and roads; the use of snow fences to prevent drifting over roads; and the use of skis, snowshoes, toboggans, snowmobiles, and sleds for travel. It is a primary factor in the location of winter sports centers and so has great economic value to certain areas. In some ski resorts machines are used to make artificial snow. As in the case of rainfall, snowfall has been produced artificially by introducing dry-ice pellets into supercooled clouds, that is, clouds containing unfrozen water droplets at temperatures below freezing.

2006-06-14 20:27:01 · answer #4 · answered by halleberry_aus 4 · 0 0

all snow is is frozen water. when it unfreezes it will be water again. a physical change is a change in apperence. a chemical change is a change in make-up. if you add enough heat to that water it would evaporate into a gas. that would be a chemical change.

2006-06-14 20:35:52 · answer #5 · answered by Daniel M 1 · 0 0

snow still has the same chemical make up as water (H2O) it is just in a different form, its only a chemical change when those bonds are broken and different substances are formed

2006-06-14 20:22:48 · answer #6 · answered by slayergurl90 2 · 0 0

It is the crystallization of water vapor onto a nucleating particle in the atmosphere. That's all there is to it, really.

2006-06-14 20:22:11 · answer #7 · answered by Anonymous · 0 0

its the same as when water turns to ice. it hasnt undergone any chemical changes such as color change, gases or energy releses. its only changing states.

2006-06-14 20:23:13 · answer #8 · answered by ayleyha 3 · 0 0

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