The eye is one of the many marvels of the human body. The colored iris of the eye, surrounding the pupil, acts as a diaphragm to keep the amount of light entering the eye fairly constant. If you walk out the door of your house to a sunny yard, the iris opening gets smaller letting less light into your eye. If you enter a dark room after watching your favorite television program, the iris gets larger to allow more light to enter your eye. This is a protective reflex, as too much light could damage the retina, which is where the image forms in the eye, similar to the film of a traditional
This lesson is motivated by a respiration study using a FLIR ONE™ thermal camera in conjunction with the Vernier Thermal Analysis Plus app. Using Voyager and the PocketLab Temperature Probe, however, allows students to investigate respiration at a fraction of the cost of a thermal camera. The response time for the Temperature Probe is rapid enough to observe temperature differences in the air inhaled and exhaled through the mouth during the process of respiration.
A spirometer is an apparatus often used in the medical field to find the cause of shortness of breath. A spirometer can rule out lung diseases like asthma, bronchitis, and emphysema. A spirometer can measure forced vital capacity. Forced vital capacity is the amount of air exhaled during a forced breath. Explore what factors affect forced vital capacity.