Unit 1 – Why Is The Rain Forest Wet?
Activity 2 – Why Does it Rain in the Rain Forest
Download Teacher Pages PDFActivity (Teacher Verison) PDF Download
Download Student Pages PDFActivity PDF Download
Materials & Setup
Class Period One
• “Maui Map Pack” acetates (masters, pp. 21-26)
• Overhead projector and screen
For each group of 3 or 4 students
• Student Page “Maui Map Pack” (pp. 28-30)
For each student
• Student Page “Why Does It Rain on the Rain Forest?” (pp. 31-34)
Class Period Two
• Three shiny metal cans
• Room temperature water to fill each can half full
• A tray of ice cubes
• Two thermometers (Celsius)
• A stirring tool
• “Condensation Demonstration Data Table” posted on the board or overhead (master, p. 27)
• “Condensation Demonstration Relative Humidity Table” posted on board or overhead, or handed out (master, p. 27)
Class Period One:
1) Draw a simple diagram on the board or overhead showing the ocean and Haleakalā. Ask students to predict what the average annual rainfall is over the open ocean. Then ask them to predict the highest annual rainfall ever measured at 1650 meters (5412 feet) in the Haleakalā rain forest. After gathering student ideas, share the actual data. Over the open ocean near Maui, an average of 56 to 71 centimeters (22-28 inches) of rain falls each year. In 1994, a rain gauge placed at 1650 meters in the Haleakalā rain forest measured more than 14 meters (46 feet or 551 inches) of rainfall in one year.
2) Ask students to hypothesize why there is such a huge difference in rainfall between the open ocean and the rain forest. Each student should write down a hypothesis. This activity will help students determine whether their hypotheses are correct.
3) Divide students into groups of three or four. Give each group a copy of the Student Page “Maui Map Pack.” Have them look at these maps and answer the questions on the student page.
4) Bring the class back together and discuss the questions on the student page. Use the acetates as visual aids, and work from the teacher’s notes to guide the discussion. (These are the same maps students received, along with a map of the location and extent of rain forests on Maui.)
5) Assign the Student Page “Why Does It Rain on the Rain Forest?” as homework.
Class Period Two:
1) Ask students to discuss the factors that affect the rainfall pattern on the windward slopes of Haleakalā, where the East Maui rain forest is. (The factors include the interplay among topography, the prevailing wind patterns, and how water behaves at different temperatures.)
2) Ask students to discuss how condensation plays into the cycle of rainfall on the Haleakalā rain forest. (They should be able to link condensation to the formation of clouds and discuss the lifting condensation level.)
3) With the class, brainstorm a list of examples of condensation from daily life.
4) So that students may see the condensation of water in action, do the “Condensation Demonstration” following the instructions (pp. 16-17).
5) After the demonstration, go through the discussion questions in the teacher background (p. 18) with the class.
6) Discuss student responses to the questions in the Student Page “Why Does It Rain on the Rain Forest?” If you need more information to help students understand the atmospheric forces that form the trade winds and trade wind inversion see Marie Sanderson (ed.), Prevailing Trade Winds, University of Hawaiʻi Press, Honolulu, 1993, or Alpine/Aeolian Unit 2 of this curriculum.
• What did you learn during this activity that confirms or refutes your original hypothesis about what explains the difference in rainfall between the open ocean and the Haleakalā rain forest?
• Have you ever been in the clouds or fog? What does it feel like compared to being in the rain?
• Participation in class discussion
• Student Page “Maui Map Pack” (teacher version, pp. 13-15)
• Student Page “Why Does It Rain on the Rain Forest?” (teacher version, pp. 19-20)
• Journal entries