3. Testing for Life - Logistics

Time
10-20 min introduction (depending on how deeply you want to talk about the biochemistry)
35-50 min to conduct tests (10-15 min per station)
20-30 min to discuss results

Grouping
Teams of 3 students

Materials
General materials for students and test stations:

• Copy of the lab handout for each student
• Copy of test station directions at each test station
• Biuret solution (see Sources section for ordering information)
• Benedict’s solution (see Sources)
• Iodine tincture
• 3 beakers or cups for every group of students
• 4 test tubes for every group of students
• 1 test tube rack for every group of students
• Permanent markers and labeling tape for the beakers and test tubes
• 30-45 eye droppers
• 6-9 trays or bins to keep the materials for each test station
• 6-9 small 100 ml beakers or squeeze bottles to contain test reagents
• Optional: 6-9 large squeeze bottles of water (500 ml disposable plastic water bottles are fine) for rinsing test tubes at test stations rather than going to a sink
• 6-9 large beakers or cups to dump waste materials
• hot plate or source of boiling water
• 2-3 insulated containers such as a thermos or Styrofoam cup for creating a hot water bath
• Optional: 2-3 thermometers to monitor the temperature in the hot water bath
• disposable latex gloves

A variety of solutions to test:

• cornstarch (mixed with water)
• milk
• glucose solution or glucose tablets (see Sources)
• chicken broth
• wheat flour (mixed with water)
• orange juice
• water
• rubbing alcohol
• diluted dish soap
• vinegar
• fish tank water or pond water
• unsweetened powdered lemonade (mixed with water)
• other substances that give interesting results include: honey (diluted in water), egg whites, potato juice, onion juice, table sugar (dissolved in water), salt water, lemon-line soda, hair conditioner, Cool Whip (mixed with water)… Be sure to choose solutions that are light in color so that you can see color changes that occur as the result of testing.

Setting
Classroom