Each group needs:

• 4 paper cups
• 4 wooden stirrers
• clear, flexible tubing (3/4-inch diameter X 5/8-inch interior diameter X 4-inch length)
• rubber stopper, a size that temporarily fits and blocks the tubing
• white glue, 60 ml
• 1 cup (~237 ml) of 4% borax solution (50 ml)
• graduated cylinder (50 ml)
• water
• marker, for labeling the paper cups
• 1 cup (~237 ml) of 1 M HCl (hydrochloric acid), such as a 1 liter bottle for $9.75 at http://Carolina.com/
• 1 cup (~237 ml) of 1 M NaOH (sodium hydroxide), such as a 1 liter bottle for $12 at http//Carolina.com/; alternatively, see note below
• 1 cup (~237 ml) of enzyme solution, such as item #15666 for $36 at Valley Vet (4-ounce Zymox Otic with 1% hydrocortisone enzymatic solution that contains three active enzymes); alternatively, see note below
• 1 cup (~237 ml) of NaCl solution (make in bulk for the class by adding 1 cup table salt to 1 gallon water and stirring rapidly until the salt is dissolved)
• 1 cup (~237 ml) of glucose solution (make in bulk for the class by adding 1 cup granulated sugar to 1 gallon water and stirring rapidly until the sugar is dissolved)
• 1 cup (~237 ml) liquid dish or laundry detergent
• 6 test tubes
• 6 droppers or pipettes
• safety goggles, one per student
• lab apron, one per student
• gloves, one pair per student
• Let the Blood Flow Student Handout, one per student

Note: The enzyme solution and the sodium hydroxide solutions could be replaced with less expensive alternatives. Only the hydrochloric acid (HCl) solution is a viable solution in this activity, thus, the other solutions (sodium hydroxide, enzyme solution, NaCl solution, glucose solution, liquid detergent) are provided so students have testing options for experimentation, ultimately discovering that they do not work. For example, for the purposes of this activity, since the enzyme solution is so expensive, replace it with any other inexpensive, readily accessible and unidentifiable liquid, perhaps an unfamiliar juice (cabbage juice?) or even Windex, and call it the enzyme solution.

To share with the entire class:

• hazardous waste bin, to collect polymer waste material
• bucket, to collect any spilled liquid during testing
• dish soap, for cleaning test tubes