What is the main idea of the passage?

Water’s sixfold ice structure and shared changing cloud conditions shape a snow crystal’s six similar arms. (The passage distinguishes the molecular source of six arms from the environmental source of detailed branches.)

Why do the six arms often develop similar details?

They travel together through nearly the same sequence of conditions. (Shared temperature and moisture provide similar growth opportunities at the same time.)

What does “symmetry” mean here?

a balanced pattern repeating around a center (The crystal’s molecular pattern repeats into six corresponding corners or arms.)

What may a wetter cloud layer encourage?

branching (The third paragraph says a slightly wetter layer can encourage branching.)

Why Snow Crystals Grow Six Arms: Level 2 Reading Comprehension Questions

A snow crystal begins when water vapor freezes around a tiny particle in a cloud. Water molecules join the growing ice in an orderly pattern. That pattern has sixfold symmetry, so a flat crystal often develops six corners or arms.

The arms grow through nearly the same cloud at the same time. They therefore meet similar temperature and moisture conditions. Each arm may form matching plates, needles, or branches. This is why one crystal can look carefully designed even though nobody planned it.

Conditions change as the crystal falls. A slightly wetter layer can encourage branching, while another temperature can favor flat plates. The six arms usually echo one another because they share the journey. No two crystals need follow exactly the same path, so their fine details can differ.

Sixfold structure comes from molecular arrangement; elaborate decoration comes from changing growth conditions. A snowflake records both an invisible rule inside ice and a visible history of its trip through a cloud.

Comprehension questions