1. Activate students’ prior knowledge about extreme weather on Earth.
Ask: What do you know about extreme weather on Earth? Encourage students to think about weather they have experienced, read about, or seen on TV or in the movies. Have students brainstorm a list of weather-related words and phrases as they “pass the marker.” Start the process by writing one weather-related word on the board. Distribute three dry-erase markers to volunteers with ideas. Have each student holding a marker approach the board and write one extreme weather word, then pass it to another student raising his or her hand. Continue until no one has ideas to add to the list. Encourage students to include words such as lightning, hail, sleet, rain, wind, gust, flood, snow, blizzard, storm, hurricane, tornado, cyclone, thunder, dust storm, and temperature.

2. View a photo gallery and video of extreme weather.
Show students images from the photo gallery Extreme Weather. Read aloud the captions as you scroll through the images. Then, show the National Geographic video “Weather 101.” Pass out the three dry-erase markers again. Have students add words related to the photos or video to the list on the board. Assist them, as needed. Then explain to students that some words from the list are weather events, and some words are part of those weather events; call the latter “ingredients.” For example, a lightning storm is a weather event. Ask: What words from our list can be part of a lightning storm? Elicit responses such as lightning, clouds, rain, wind, and thunder. 

3. Have students complete the worksheet Weather Investigation.
Distribute a copy of the worksheet Weather Investigation to each student. Read aloud the directions and go over the provided answer. Allow students to gather and organize the information they have learned about weather and conditions present for each type of weather. Have students work in pairs or as a whole class to identify other weather events and the ingredients for each from their list. Help students to find answers to any questions they have, including definitions of words that are new to them. Their answers should include the following:

• Thunderstorm: rain, clouds, lightning, thunder, wind
• Tornado: clouds, strong wind, rain, hail
• Hurricane or cyclone: strong wind, heavy rain
• Blizzard: heavy snow, ice, cold temperatures
• Dust storm: strong winds, arid conditions
• Flood: heavy rainfall
• Hail storm: cold or warm temperatures, rain, ice
• Ice storm: freezing rain

4. Discuss the ingredients of extreme weather events.
Ask: How are the ingredients for each weather event the same? How are they different? Help students to identify that many weather events have certain ingredients in common, including wind, clouds, and high or low temperatures.