Lesson 4: Boyle's law

P1V1 = P2V2

  • Hook: Discussion of pressure. “What does it mean when your blood pressure is high/low?”, “Why do our ears pop at high altitudes?”, “What does ‘putting pressure’ on something mean?” Accompanied by pictures as follows. Students should come up with the idea that pressure means a certain amount of force is acting on an area. For the purposes of this unit, gas molecules will be the objects exerting force on the inside of their containers creating pressure.
https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcTOuVOjNhc9px9tkaGIvVlYcYZvbbg9DfrGrZjEc0BLTPPqu7q_
                    • Figure F.15 - Taking blood pressure
                    • Figure F.14 - Mountaintop view
                    • Figure F.16 - Applying pressure to garlic
  • Action: Students will learn the Boyle's law formula and will perform a small activity in order to reinforce the inverse relationship between pressure and volume. The activity uses a syringe and marshmallow to demonstrate Boyle’s Law. As students push the plunger of the syringe closer to the tip, this increases the pressure inside the syringe causing the marshmallow to collapse in on itself. However, if students pull the plunger out farther from the tip, the pressure will decrease in the syringe causing the marshmallow to expand in volume.
  • Debrief: Exit slip – “Using Boyle’s Law, why DO our ears pop at high altitudes?”. Asking students this question will help give reason to what was discussed earlier when discussing pressure. Students should be able to apply what was taught in the lesson regarding pressure and volume with their knowledge on the anatomy of the ear.