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Investigating Human Respiration (Developed by SEPUP)

kit #803S

Students explore the role of the respiratory system in the regulation of gases in the blood. Students qualitatively investigate the use of bromthymol blue (BTB) as an indicator. They then quantitatively measure the amount of carbon dioxide in their exhaled breath by using the indicator to perform a simple titration.


  • Creating models is one way to understand and communicate scientific information
  • Each system within the human body is defined by the functions that it performs
  • Lungs provide surface area for oxygen to enter and carbon dioxide wastes to leave the blood
  • An indicator can help measure changes, such as shifts in the concentration of carbon dioxide present in a solution

Content List in Investigating Human Respiration (Developed by SEPUP) is as follows:

Quantity Description
1 Teacher’s Guide with MSDS
32 Student Worksheets and Guides
24 Plastic cups
4 Bromthymol blue (BTB) Indicator, Dropper bottle
8 0.05 M sodium hydroxide, Dropper bottle
8 SEPUP trays
8 Droppers
16 Stir sticks
16 Cups, 30-mL, graduated
16 Plastic bags, 1-gallon
18 Straws
Number of students
Number of groups
Maximum 8 groups per period

To complete this kit requires one to two ~50-minute class periods.

Title Item # Price Quantity
Investigating Human Respiration (Developed by SEPUP) 803S $148.85
Investigating Human Respiration REFRESH-A-KIT 803S-RC $57.45