Rainforest Deforestation and the Water Cycle

By Angie Cargill and Shawna Steward

Objective:

Students will use data and technology to develop an understanding of the relationship between deforestation of rain forests, the water cycle, and their daily lives.

Standards met in this unit:

  • Math:  4.5.1  By the end of 4th grade, students will collect, organize, represent, and interpret numerical and categorical data and clearly communicate findings.
  • Science:  4.1.1  By the end of 4th grade, students will develop an understanding of systems, order, and organization.
    -Relate how parts of a system affect a whole system. 
  • 4.1.2  By the end of 4th grade, students will develop an understanding for evidence, models, and explanation. 
  • 4.1.3  By the end of the 4th grade students will develop an understanding of change, constancy, and measurement. 
  • 4.2.1  By the end of 4th grade, students will develop the ability needed to do scientific inquiry. 
  • 4.4.3  By the end of 4th grade, students will develop an understanding of living things and environment.
  • 4.7.3  By the end of 4th grade, students will develop an understanding of environmental changes.

Prior Knowledge:

Students have a definition of a rainforest. They have explored the importance of the rainforest and its products on the economy in the areas around it.

Day 1

Engage:  (Prior to class the teacher will have prepared two large terrariums with soil and planted with a mixture of large and small plants.)  Teacher displays the two terrariums as the students enter the classroom.

Students verbally brainstorm on which of the various biomes the terrariums could represent.

This week we will be using our terrariums to represent tropical rainforests and to demonstrate the water cycle.  

The way the terrarium works.

Plants will not suffocate in a closed container because they can use the same air over and over again.  In daylight, plants take in carbon dioxide and give off oxygen.  Using carbon dioxide and light, plants produce food.  At all times plants use food and oxygen to produce energy, which turns into carbon dioxide again.  Water is also recycled in a terrarium.  This happens as plants take water from the soil and then release it through their leaves as water vapor.  In a closed container, this vapor turns into water droplets.  The water drips back into the soil to be used all over again. 

Discuss how the rain forest helps the whole Earth’s ecosystem as it continues to function as a closed environment.  Use the air in the bottle to simulate the Earth’s atmosphere. The plants change carbon dioxide into oxygen and the Amazon Rain Forest sends the fresh air out to the whole world.

Materials

  • Heat source (heat lamp or light bulb).
  • Tropical houseplants
  • Seeds: carrot (for the fluffy fern-like plants), bean seeds (to simulate vines), passion flower seeds
  • Soil
  • Plastic bottles
  • Ruler
  • Student journals (notebook)

Procedure

  1. Directions for making terrarium.
    1. Rinse out the plastic bottle.
    2. Cut the plastic bottle about midway.  You will use only the rounded clear part for this project.
    3. Pull the colored bottom away from the clear plastic.
    4. Fill the colored plastic bottom of the bottle with soil.
    5. Arrange the plants in the soil.  Drop seeds around the soil.
    6. Add about one-eighth of a cup of water to the soil.
    7. Place clear plastic rounded part tightly on colored bottom.
    8. DO NOT OPEN AGAIN.  The water cycle will be working.
  2. Have students place terrariums in various places around the room (next to window, away from the window, or near a heat source).
  3. Students will note the plant growth by taking daily measurements from the outside of the bottle.  Each student will keep a journal with the information they gather.

Day 2

Engage:  (Prior to class, place ice on top of the large classroom terrariums.)  When students have entered the classroom, have them describe what is happening in the terrariums.  On the chalkboard, write:  What is happening in our terrarium rainforests?

Students then brainstorm verbally and record on the board what processes are occurring within the terrarium. 

Explain:  Clarify the stages of the water cycle that are occurring by labeling them on the outside of the terrarium. (Can use sticky notes with labels:  precipitation, evaporation, condensation, accumulation, and transpiration) 

After some discussion of the placement of the labels, display an overhead of a water cycle.  (An illustration of a water cycle can be found on page 98 of AIMS Education Book, Primarily Earth K-3.)

This is a system within the rain forest.  It is receiving input, output, and has properties and characteristics. 

During and after discussion, students will label and define stages of the water cycle on an activity sheet resembling the overhead. 

Explore:  Try It Activity  (making a water cycle in a plastic bag)

Try It!

You can make your own water cycle:

  1. Put two teaspoons of water in a small plastic bag.
    2. Blow air in and seal the bag with a heavy rubber band.
    3. Place the bag in a sunny window.

What do you see?

The sun provides the energy to make the water cycle work.

  • Heat from the sun evaporates water from surfaces including lakes, rivers, and oceans, putting water vapor into the air.
  • As the water vapor cools, it condenses, forming tiny droplets in clouds.
  • The clouds meet cold air and the water falls down to the Earth's surface as precipitation --rain, sleet, or snow.
  • Some of the precipitation soaks into the soil. This water is either used by plants or stays as a layer of underground water called groundwater.

Day 3

Prior to class the teacher needs to remove several large plants from one terrarium and place ice on top of terrarium again. 

Engage:  Students will get into groups and list the properties and characteristics within the rainforest system, which contribute to the systems input and output.  (Examples: trees, sunlight, and the thick layer of decaying matter on the floor of the rain forest.) 

Explore/Elaborate:  Students will explain why there are differences in the terrariums, in terms of the water cycle.  List suggestions on the board.

What has occurred here is called deforestation.  

Explain:  As a group, students will generate their own definition of deforestation.  Have students write definition on a large sheet of paper and post it on the wall. 

Evaluation:  Students will predict what changes will occur as a result of deforestation in the rainforest.  A webbing activity at the chalkboard, connecting the related factors could be used. 

Day 4

Engage:  (Prior to class, empty bags of Peanut M&M’s and replace candy with plain peanuts.)  Give each student a bag of “Peanut M&M’s”.  Today we get to enjoy a product of the rain forest.  You may eat your candy.

As the students open their candy, they will discover the missing chocolate.  Is there something wrong with your candy?  

Explore:  Students working in pairs will access the Internet and find information pertaining to the effects of deforestation on the water cycle and local economies.  For younger students websites should be located or given.  Older students should be directed to certain sites, but allowed to do the exploring under supervision. 

Day 5

Students will be assigned their final evaluation.  They will be required to work in teams of 2 or 3 to compile a "project”   showing the effects of deforestation of rainforests on the water cycle and local economies.  Students may want to brainstorm ideas on how to do this.  Examples might be a Hyperstudio movie or book, poster, collage, diorama,  skits, written reports, or creating a game.  Class time for at least 2 days could be set aside for this purpose.  Students should also compile the data collected from their personal terrariums into a graph.  This information could be used in their final project as well.  A rubric would be used to evaluate the final projects created by the student teams.