Introduce the parts of respiratory system by making a model using straws of different sizes and Q-tips. Large size straws using straw from bubble tea, regular straw and a narrow straw, such as those for hot coffee (but don’t forget to cut it through the middle).
Start with the bubble tea straw to represent trachea, then regular straws to represent bronchi, coffee straws as bronchiols and finally the cotton end of Q-tips as alveoli (similar to the sac-like shape of alveoli). What you’ve done is a model to represent the passageway of air as you breath in and out.
Use of analogy
You can also compare this to the road system, for example…
Bronchi ≈ Exit of expressway (unlike expressway with multiple exits, there are only 2 bronchi in our body)
Bronchiole ≈Regular roads (branches off to streets and avenues, similar to branching observed in bronchiole)
Alveoli ≈ Carpark (loading and unloading taking place in carpark is similar to gaseous exchange taking place in alveoli)
2. Model of lungs
What’s the science behind it? When you pull down the knotted balloon, it increases the volume in the bottle, which lowers the pressure. As the environment has high pressure than the model, air rush in (because air moves from high to low pressure), hence inflating the balloon in the bottle. As the knotted balloon is released, volume in the bottle decreases, hence pressure increases. Hence, air moves out from the balloon and it deflates.
How similar is the model to lungs?
The knotted balloon in the model represents the diaphragm. Diaphragm is dome-shaped muscles located below the lungs. Its rhythmic contraction and relaxation results in breathing. Pulling down the knotted balloon is similar to diaphragm contracting. When the diaphragm contracts, it moves downwards, increasing volume of chest cavity.
When the knotted balloon is released, it represents relaxation of diaphragm. The diaphragm moves upwards when it relaxes, decreasing the volume of chest cavity.
4. Chest measurement
During inhalation, chest moves upwards and forward as it expands.
Grab a measuring tape to do a simple activity with your child. Lets compare the measurement of chest during inhalation and exhalation. Your child can compare the measurement and you can use this results to link to concepts of breathing. Also, let your child to do it on friends and family members too to inculcate scientific skills such measurement and communicating data.. You can use template here to record the results.
Extension (for 10 years old above)
Make it into project for your child as he/she do the measurement on friends and family members. Extend it for your child to make it into a report or poster to incorporate science skills and elements of STEAM.
Incorporation of STEAM (where applicable)
Science skills: measurement, recording results, communicating data into table/graph
Technology: Use of Powerpoint to make poster/report
Art: Design of poster/report
Math: Use of table, comparison of data
Here’s another idea for a science project. Why not compare the breathing rate for various activities?
To determine breathing rate, count for each time you breathe in for 1 minute.
Through this activity, you can introduce the concept that breathing rate increases during strenuous activity.
Science behind it
During physical activity, such as running, the muscle cells need more energy. Breathing rate increases to transport oxygen at a faster rate to cells to increase the rate of respiration, hence release more energy.