Breathing And Boyles Law

• databot

• IOS/Android Smart Device

• 1 L plastic bottle

• 2 small balloons (9”)

• 1 large balloon (12”)

• Pneumatic tubing (5 mm)

• #4 two-hole stopper (or modified
  cap)

• Rubber bands

• Electrical tape, Velcro plate/strip

Breathing happens because of changes in air pressure
inside your chest. Your lungs sit inside your chest
cavity, and a large muscle called the diaphragm helps
control breathing.

When the diaphragm tightens, it moves downward and
makes more space inside the chest. When this space
gets bigger, the air pressure inside the lungs becomes
lower than the air outside your body. Air then moves
into the lungs. This is called inhaling.

When the diaphragm relaxes, it moves back up and
the space inside the chest gets smaller. The air
pressure inside the lungs becomes higher than the air
outside. Air moves out of the lungs. This is called
exhaling.

This works because of a rule called Boyle’s Law,
discovered by Robert Boyle. Boyle’s Law states that
for a gas at a constant temperature, pressure and
volume are inversely related. This means that when
the volume of a gas increases, its pressure decreases.
When the volume decreases, its pressure increases.

This physical principle explains how breathing works.
The lungs do not actively pull air into the body.
Instead, muscle movements change the volume of the
chest cavity, which changes the air pressure. Air then
moves automatically due to these pressure
differences.

Overview

Background

What You Will Need/Prep

• Test your databot™ connection.

Have you ever wondered how air gets into your
lungs? Do we “suck” air in? Or does something else
cause air to move? Today, we will discover that
breathing is not about sucking air — it’s about
pressure differences.

• Install Vizeey™ on your
  Smart device.

• You will be prompted to select
  and connect to databot™ each
  time you launch an experiment.

• Study the background
  information and terms and
  prepare to explore!

Grades: Middle School

Time: 45 Minutes

Subject: Life Science & Physical
Science

Topics: Respiratory System, Boyle’s
Law, Air pressure, Volume changes

• Scan the QR code to load
  the experiment.

Breathing and Boyle’s Law

Learning Objectives

In this investigation you will master the following knowledge and skills:

• Visualize, collect and analyze data

• Build a functional lung model

• Measure air pressure changes during simulated breathing

• Interpret air pressure vs. time graphs

• Explain breathing using Boyle’s Law

• Connect a scientific law to a biological system

Air Pressure: The weight of the air above us pressing down. We don’t feel it normally
because it is always there, but air has weight!

Boyle’s Law: The law stating that pressure and volume of a gas are inversely proportional.

Diaphragm: A dome shaped muscle-membrane that separates your thorax from your
abdomen. It plays a major role in breathing by contracting and changing the volume in your
chest cavity which allows fresh air to rush in and deliver oxygen!

Exhale: To breathe out.

Inhale: To breathe in.

Respiratory System: your lungs, airway, and associated muscles, are responsible for
breathing – taking in oxygen and expelling carbon dioxide.

In this investigation, you will build a working lung model and measure air pressure changes
inside it using databot.

You will explore Boyle’s Law, a scientific principle that explains how pressure and volume
are connected, and see how this physical law controls every breath you take.

In order to work with the experiment, you need to launch Vizeey application and click on +
in the upper right corner.

Then select “Add experiment from QR code” and scan the QR code prepared for this
experiment. Your experiment will appear in the list.

When you start the experiment you will be
immediately offered to connect to your databot. Make
sure that databot is enabled.

• If there are two or more databot's listed, the one
  closest to your device will be highlighted.

Part 2: Hypothesis

Part 3: Experiment Procedure

Prepare:

• databot

• 1 Liter plastic bottle – 1

• 9″ Balloons – 2

• 12″ Balloon – 1

• Pneumatic tubing (5 mm)

• Rubber bands

• Electrical tape

• #4 2-hole stopper (or modified cap)

• Velcro plate/strip

Part 3: Experiment Procedure

Setup

Refer to the pictures below to assemble your lung with databot™ inside!

Attach the 9″ balloons to
the pneumatic tubing.
with rubber bands. These
are the lungs.

Slide pneumatic tubing with
balloons into the #4 2-hole
stopper. (You can use a
bottle cap by making two
holes in it for the tubes and
then sealing them securely.)

Cut the bottom of your
bottle (just above the
ridge) and measure from
the bottom up 3 1/2″ and
mark.

Attach the plate with the
velcro to the inside of the
bottle at the 3 1/2″ mark
with the ridges pointing to
the bottom of the bottle.
This is your diaphragm.

Slide databot on

the velcro plate.

Cut your 12″ balloon

2 1/2” from the top.

This is what your
balloon should look
like.

Stretch the balloon across
the bottom of the bottle.

2 1/2 ”

Use about 12″ of electrical
tape to secure the ballon
to the bottle.

Insert the stopper with
the balloons into the top
of the bottle. Lungs done!

• Turn on your databot by gently squeezing your bottle and pressing the switch through
  the plastic.

• Tap on Breathing experiment in Vizeey.

  • Hint- if there is more than one databot in use, the one closest to you will be in blue!

  • A solid blue light on databot means you are connected.

• Start your data collection using .

• Record resting pressure in the table below.

• Now gently pull on the diaphragm:

  • This will increase the volume in the “chest cavity” and the higher pressure air
    outside the chamber will push in and fill the lungs.

  • You’re simulating inhalation.

• Release diaphragm.

  • Observe balloons deflate.

  • You’re simulating exhalation.

• Record pressure every 10 seconds.

Part 3: Experiment Procedure

Data Collection Table

• Watch the lungs and the data being displayed by
  databot as your model lungs breathe.

• Experiment with the diaphragm and practice
  breathing at 15 breaths per minute, that is a breath
  every four seconds.

  • Observe repeating air pressure patterns.

Now that you have collected your data, it is time to analyze your results.

• Create a Pressure vs. Time graph.

• Identify:

  • Lowest and highest pressure. What does it correspond to?

• Describe pattern shape.

• Compare pressure values during:

  • Increased volume

  • Decreased volume

1. How does Boyle’s Law explain everyday breathing?

1. Why is understanding pressure important in medicine (e.g., ventilators)?

1. How does this demonstrate Boyle’s Law?

1. What happened to pressure when volume increased?