Part of the confusion in this lab activity is related to the names given for different values in the data table and for some missing terms in the instructions.
It will help if you review what the student is trying to determine in this exercise.
This lab activity looks at the role of nasal passageways in warming air during breathing. The student breathes in through the nose and then out through a straw that has a surface temperature probe attached to it. They then determine the change in temperature when inhaling through the nose. They then store the run and repeat the breathing activity while inhaling and exhaling through the mouth.
It will help if you try to remember that Run 1 is nose inhalation and Latest refers to mouth inhalation.
The student needs to calculate the change in temperature for Run 1 (nose inhalation) and the change in temperature for Latest (mouth inhalation).
As stated in the introduction, if we assume that the warming from the esophagus and mouth is negligible, then the change in temperature during mouth inhalation represents the warming due to just the lungs. This is referred to in the exercise as delta T (Latest).
The change in temperature during nose inhalation represents warming from the lungs and the nose. This is referred to as delta T (Run 1)
If you subtract delta T (Run 1) from delta T (Latest) you can calculate the portion of the warming that is just from the nose. This is simply referred to as delta T.
Part of the confusion comes from the teachers section. There are some typos in the Answers To Data Analysis Questions” section. These typos are corrected below.
Answer to Question 2 should state
“The difference between exhaled temperatures from nose and mouth inhalation is divided by the change in temperature for nose inhalation. Multiply this value by 100 to get values in percent. Values should range between 10-15%.
Answers to Question 3 part A and Part B have typos in the equations.
In part A, the equation is stated as delta T (Run 1) – delta T / 160 cm^2. This should be written as delta T (Run 1) – delta T (Latest) / 160 cm^2.
In part B, the equation is stated as delta T (Latest) – delta T / 1 x 10^6 cm^2. This should be written as delta T (Latest) / 1 x 10^6 cm^2.