Time

Safety

1. Students should wear protective goggles throughout the laboratory exercise.

2. Students should be aware of hydrogen peroxide's stinging on open cuts or wounds. Disposable and inexpensive “latex” or health gloves can be provided (also useful when working with liver tissue)

General Safety Guidelines

Materials and Apparatus

• Pieces of fresh (not frozen) liver, each about 6 mm in "diameter"
  
• Pieces of fresh potato
  
• 100 ml of 3% hydrogen peroxide (fresh from drug store)
  
• Manganese dioxide (MnO₂) powder
  
• Distilled water
  
• Fine sand
  
• 3 test tubes, 18 x 150 mm (preferable that they have a permanent white patch for marking with pencil)
  
• 250-ml beaker
  
• Test tube rack (or small beaker with paper towel padding on inside, bottom)
  
• Forceps
  
• Mortar and pestle
  
• Hot plate or electric "tea" kettle (for providing hot water in 500-ml beakers that groups of students can access when needed; they should not be making their own hot water) clean-up containers (old soda bottles with top cut off down to the main body of the bottle) for sand and manganese dioxide.

Advance Preparation

1. Set up hot water stations, using 500-ml beakers on hot plates; quick heating of water can be done with a “tea kettle” type hot water heater.

2. Provide vials with manganese dioxide (equivalent of 3 to 4 spatula tips full) and sand.

3. Hydrogen peroxide can be set out in 125-ml flasks on lab tables for group use. If taken from the refrigerator, make sure the liquid is at room temperature.

4. Cut liver and potato into useful sizes (6 mm in diameter)

Relevant National Science Education Standards

Unifying Concepts and Processes — The activity involves measuring the changes wrought by altering catalysts in a reaction system and drawing conclusions from evidence.

Science as Inquiry — The activity involves conducting systematic observations, interpreting and analyzing data, drawing conclusions, and communicating results.

Physical Science — The activity is concerned with chemical reactions.

Life Science — The activity has applications in understanding the cell as well as matter, energy, and the organization of living systems.

History and Nature of Science — The activity demonstrates the nature of scientific knowledge.

Relevant New Jersey State Science Education Standards

5.1	The activity involves conducting systematic observations, interpreting and analyzing data, drawing conclusions, and communicating results.
5.3	The activity is mathematically based.
5.6	The activity investigates the chemical behavior of matter.