LABORATORY 1
Effective Physics Teaching Includes Laboratory Activities
as an Integral Part of Classroom Instruction
By Leona Marie C. Camano
Activity on Model of the Human Chest Cavity
Objectives
Materials
1. Explain how the lungs work,
2. Describe how the movement of the diaphragm helps the air go in and out of the lungs, and
3. Relate the model to human lungs
1 two-liter empty plastic bottle with cap, 3 balloons (1 big, 2 small), 2 sturdy straws, 1 pair of
scissors, and 3 rubber bands or tape
When you breathe in, a muscle under your chest called the diaphragm contracts, and your ribs
expand. This expansion of the space reduces air pressure in your lungs. Outside air will rush in.
When you exhale, your diaphragm moves upward, and your ribs return causing the air to move
out of the lungs.
Concepts
Figure 1
The model works in a similar way: When you pull on the larger balloon, the space within the
bottle expands, and the air expands. Because the pressure within the container is now lower, the
higher pressure outside pulls air in. (This is similar to breathing in.)
When you push in the larger balloon, the air within the bottle becomes compressed, which
increases the pressure. This higher pressure sends the air out of the balloon. (This is equivalent
to exhaling).
Make a Model of Your Lungs
1. Using a pair of scissors, cut the bottom out of a 2-liter empty plastic bottle.
2. Create one hole in the cap of the plastic bottle. Make sure that the hole is just big enough for
a straw to fit through.
3. Attach one straw to each other, to form like a branch.
4. Place one balloon in the end of each straw, and secure them with rubber bands or tape, as
shown in Figure 2.
Procedure
5. Stick the straw through the hole of the bottle cap, then locked it tightly on the lid. Refer to
figure 3.
6. Stretch out the larger balloon and place it over the open bottom of the bottle. Secure it with
the rubber band or tape as tightly as possible. Refer to Figure 4 of the finished lung model.
7. Pull the larger balloon down; that is, away from the bottle, to blow up the two small balloons.
8. Push the larger balloon towards the bottle to let the air out of the two small balloons.
1. What does each part of the constructed lung model represent?
Guide
questions
2.
3.
4.
5.
6.
7.
8.
9.
What happens as you pull down the balloon at the bottom of the model?
What happens as you push up the balloon?
How does the movement of the diaphragm cause the air to go in and out of the lungs?
What might happen if you prick the large balloon?
Why did the small balloons inflate when you pull down the large balloon?
Why did the small balloons deflate when you push up the large balloon?
How pressure affects the movement of air in and out of the lungs?
Relate the inflation and deflation of the small balloons to your lungs.
Criteria
Discussion
Questions
Organization
Rubric
Cooperation and
Teamwork
Presentation
5
All discussion
questions
thoroughly and
clearly explain on
the relationship of
the model to the
human lungs
Materials are
complete and
organized to
present the ideas
well.
Members are on
tasks and have
defined
responsibilities at
all times.
Presenters are
confident in the
delivery, and they
did an excellent job
of engaging the
class.
4
3
2
Only two discussion
questions are
answered.
Only one
discussion
question is
answered.
Materials are
complete and well
organized.
Some materials are
complete and
organized.
Materials are
incomplete and
not organized.
Members have
defined
responsibilities
most of the time.
Most members
know their
responsibilities but
have no defined
responsibilities.
Presenters are not
consistent with the
level of confidence/
preparedness they
showed but have
some strong
moments.
Members do not
know their task
and have no
defined
responsibilities.
All discussion
questions explain
on the relationship
of the model to the
human lungs
Presenters are
occasionally
confident with
their presentation
however the
presentation was
not engaging.
Presenters are
unconfident and
demonstrated
little evidence of
planning prior to
the presentation.
Proof of Implementation
References
Respiratory and Circulatory Systems (2020). Sci-Box (A Self-Learning Package) for JHS for Grade 9. Module 1.
Department of Education, Iloilo.
Lungs Expanding and Contracting.
https://www.google.com/url?sa=tsource=web&rct=j&url=https:///www.sfi.ie/site-files/primaryscience/media/pdfs/col/lungs_activity.pdf&ved=2ahUKEwj_cDivbb6AhWLtlYBHYW9CPkQ6sMDegQILRAB&usg=AOvVaw0TPNicdDaHsU0O2wxzVON