Glass lung (Casey Hayes)
AuthorCasey Hayes-
Biology and Physiology
Principles
Anatomy & Physiology
Respiratory System
Mechanisms of Breathing
Physics of vacuums
Standards
HS-LS1-3 - Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis.
HS-LS1-4 - Develop and use a model to illustrate the hierarchical organization of interacting systems provide a specific function in an organism.
Materials needed
Bell jar apparatus (jar, glass tubing)
Balloons
Gatorade bottle
Straws
Glue
Clay
Procedure
Students will first have the ability to study the respiratory system. Lectures will be given before hand and the pathway of the air is explained. Students can see that the lung is expanding, but why is that? are we pulling air into our lungs?
Students will cut the bottom of the plastic bottle and place balloons on the top of the bottle and on the bottom.
Explanation
The cavity inside the bell jar is airtight. As the diaphragm is pulled down, the volume of the cavity increases. This causes the pressure to decrease. Air rushes in to equalize the pressure, causing the balloons to inflate. As the diaphragm returns to it's original position, the volume of the cavity decreases. This causes an increase in pressure within the bell jar, the air rushes out of the balloons causing them to deflate. This is an excellent model to use with classes studying animal respiration or health applications.
Students have trouble seeing that the release of air from the bottle is strongly due to the vacuum that happens when the muscle increase the size of the chamber with allows the air to come into the body, this is all a reason why we can't breath through a tube that is too long when under water.
Questions
What does each part of the model represent?
rubber sheeting = diaphragm
balloons = lungs
tube = glottis
bell jar = chest cavity
Move the rubber sheeting down and describe what happens. Then, move the rubber sheeting back to it's original position and describe what happens.
As the rubber sheeting is pulled down, the lungs inflate. As the rubber sheeting returns to its original position, the lungs deflate.
Repeat with the tube closed. Describe what happens.
When the tube is closed, the lungs do not inflate as the rubber sheeting is moved down.
Everyday examples of the principles illustrated
Mechanisms of Breathing
Respiratory System
Concentration gradients