Lesson 3 Enrichment

Model a Repository

Purpose:

This enrichment activity provides a hands-on approach that introduces students to some of the principles involved in designing a repository to isolate nuclear waste.

Concepts:

1. Water moves through porous material by capillary action
   
   
2. Different materials with differing porosity and capability will absorb
   or transmit water.
   
   

Duration of Lesson:

One 50-minute class period

Objectives:

As a result of this lesson, the student will be able to:

1. Follow directions and work in a team atmosphere
   
   
2. Create a plan or strategy and then execute the plan
   
   
3. Design a plan to use the properties of materials to prevent water
   coming in contact with a cotton ball soaked in food coloring
   
   
4. Apply concepts to a real life situation (water coming in contact with
   waste packages in a repository)

Skills:

Critical thinking, discussing, simulation, working in groups, handling porous material, applying concepts, planning, and developing a strategy

Vocabulary:

absorb, capillary action, isolation, permeability, porosity, repository, strategy, transmit

Materials:

Provided by students:

• Half-liter or one-liter clear, plastic bottles

Provided by teacher:

• Stopwatch
  
  
• Scoops or spoons
  
  
• Plastic sheeting
  
  
• Water (approx. 20 ounces)
  
  
• Paper plates
  
  
• Small, pre-cut squares of cheesecloth (3X3-inches)
  
  
• Paper towels
  
  
• Rubber bands
  
  
• Cotton balls
  
  
• Food coloring

Material for isolation or containment:

• Styrofoam peanuts
  
  
• Potting soil
  
  
• Clay—kitty litter
  
  
• Clean sand (medium to coarse)
  
  
• Gravel or pebbles
  
  
• Plaster of paris
  
  
• Modeling clay

Activity Sheet: Water Flow in a Repository

Suggested Procedure:

The objective of this activity is to design a method of burial to prevent water from coming in contact with the cotton ball (representing nuclear waste) and from moving food coloring (representing radioactive particles) to a different location (out of the bottle).

1. Cut the bottom off the plastic bottle.
   
   
2. Cover the neck end of the bottle with cheesecloth and secure with a rubber band.
   
   
3. Invert the bottle with the large end up and fill about half way with an assortment of various earth materials (sand, potting soil, kitty litter, gravel, and pebbles) to build up layers
   
   
4. Soak a cotton ball in food color (this represents the radioactive waste).
   
   
5. Using any combination of the containment materials, allow students to design a containment system for the cotton ball in any order or arrangement they choose.
   
   
6. Fill the remainder of the bottle with layers of earth materials.
   
   
7. Hold the bottle over a paper plate and simulate precipitation by adding water to the surface (large open end) of the bottle. Start the stopwatch when adding the water.
   
   
8. Note how long it takes for the water to infiltrate to the cotton ball and start moving food coloring below the level of the cotton ball (leave stopwatch running).
   
   
9. Note how long it takes until colored water leaks out of the bottle and onto the paper plate.
   
   
10. Have students answer the questions on the activity worksheet and discuss their answers.
    
    
11. As a class, have students describe their strategies for success and lessons learned. Ask:
    
    What lessons were learned from failures?
    
    What was the root cause of the failures?
    
    What were some of the problems with equipment?
    
    What were successful operational strategies?
    
    How real was this activity?
    
    Note: You may want to set up a chart for students to record the time it took for water to reach the cotton ball and the time it took for the colored water to drip into the paper plate. Award points for the slowest times, which show the best repository design.
    

Teacher Evaluation of Student Performance:

Student participation in class discussion and completion of the activities will indicate understanding.