ACT Practice-English

Front

Snowflakes form from tiny water droplets, following a specific process of chemical bonding as they freeze, which results in a six-sided figure.

Back

No change

Front

The rare "triangular" snowflake, similarly, confounded scientists for years because it apparently defied the basic laws of chemistry.

Back

however,

Front

The seemingly triangular shape of those snowflakes suggests that forming through a different process of chemical bonding.

Back

that they form

Front

By re-creating snowflake formation, a discovery has revealed to scientists Kenneth Libbrecht and Hannah Arnold the cause of this apparent variation.

Back

scientists Kenneth Libbrecht and Hannah Arnold have discovered the cause of this apparent variation.

Front

Snowflakes begin to form when water in the atmosphere freezes it causes the water molecules to bond into a hexagonal shape.

Back

freezes, causing

Front

During the flake's descent from Earth's upper atmosphere, other water vapor molecules bumps into the hexagonal structure.

Back

bump

Front

In 2009, Libbrecht and Arnold's experiments revealed that triangular snowflakes begin with the same process of chemical bonding and forms a hexagonal shape.

Back

form

Front

The triangular shape is an illusion resulting from one significant addition to the process dust.

Back

process:

Front

Triangular snowflakes begin to form when a tiny dust particle or other such impurity collides with the flake as it falls, thereby pushing one edge upward. The greater the pressure from the wind, causes bonds to form quick at this edge than in the rest of the snowflake.

Back

pressure from the wind

Front

The greater the pressure from the wind, causes bonds to form quick at this edge than in the rest of the snowflake.

Back

more quickly