Question

how to make working model of lungs

Answer 1

$\:\:\:\:\:\:\:{ \underline{ \bigstar\boxed {\bold {Aim : }}}} \:$

To make a model of the lungs in order to study how they work

$\:\:\:\:\:{ \underline{ \bigstar\boxed {\bold {Materials \: Required : }}}} \:$

Balloon, bell jar, rubber sheet, glass tube or straw, one-holed cork, thread

$\:\:\:\:\:\:{ \underline{ \bigstar\boxed {\bold {Method : }}}} \:$

Assemble a model of the lungs as shown in the diagram. Make sure that the cavity inside the bell jar is airtight. Now, pull the rubber sheet down carefully. What do you see? Let the rubber sheet go back to its original position. What do you see now?

$\:\:\:\:\:{ \underline{ \bigstar\boxed {\bold {Observations \: and \: conclusions : }}}}$

When you pull the rubber sheet down, the volume of the cavity increases. This decreases the pressure inside the bell jar. Air rushes in through the glass tube to equalise the pressure, causing the balloon to inflate. When you let the rubber sheet go back to its original position the volume in the bell jar decreases. This increases the pressure inside the bell jar. Air rushes out causing the balloon to deflate. This model mimics the action of the lungs.