Assist second-graders in learning cloud types by categorizing them into low, middle and high clouds. Low or stratus clouds, do not usually indicate rain. They cover the sky in a grayish blanket that sometimes blocks the sun or moon. Middle clouds of various types all have the prefix "alto" and may indicate the chance of rain. Alto clouds may be stratus or cumulous clouds. Cirrus clouds are high clouds that may appear in long, thin bands or many small puffs. The prefix "cirro" before a cloud type indicates it is a high cloud.
Explain cumulus clouds to second-graders by comparing their appearance to cotton balls. These are the types of clouds kids most often draw. When cumulus clouds grow to look like puffy towers of cotton balls, a storm may occur. These towers of cumulus clouds most often produce thunder, lightening, high winds and tornadoes.
Have second-graders practice adding the prefix "nimbo" or suffix "nimbus" to a cloud type. Explain that adding this prefix or suffix to any cloud name changes the meaning to indicate that the cloud is producing or will produce rain. For example, a stratonimbus cloud is a low, blanket-looking cloud that covers the sky and produces rain.
Explain that clouds look different colors because of the different amounts of water and ice in them. White, puffy clouds have water particles that are spread out and reflect light, making them appear white. Clouds that appear gray have many water or ice particles pushed next to each other. The light does not reflect and so the cloud appears gray. Gray clouds mean the cloud is full of participation that may begin to fall soon. Describe fog to second-graders as a type of cloud too. Fog is a thin, very low stratus cloud that touches the ground.