The video explains the piezoelectric effect, where certain crystals generate a voltage when compressed or subjected to mechanical stress. The host demonstrates this using a BBQ lighter, which uses a piezoelectric crystal to create a spark. He then delves into the molecular structure of quartz, explaining how the arrangement of silicon and oxygen atoms creates a polar bond, leading to the piezoelectric effect.
The host explains that any crystal can be piezoelectric if it meets two criteria: having polar bonds and lacking a certain type of symmetry. He also shows how the piezoelectric effect can be used as a sensor, creating a voltage when compressed, and can even be used as a microphone or speaker.
Finally, the host mentions the use of the piezoelectric effect in quartz watches, which vibrate at a precise frequency, and teases a future video on the subject. The video concludes with a promotion for CuriosityStream, a subscription streaming service featuring documentaries and non-fiction titles.
1. When you press down on the trigger of a BBQ lighter, you have to put some effort into it.
2. The effort is required to work against a stiff spring in the lighter.
3. The compressed spring stores potential energy.
4. The spring is released when the mechanism gives way.
5. The potential energy stored in the spring is turned into kinetic energy in a hammer.
6. The hammer strikes a piezoelectric crystal in the lighter.
7. The piezoelectric crystal generates a voltage across the crystal when hit.
8. The voltage produced is high enough to make electricity jump across a gap.
9. The spark produced by the electricity can ignite a flammable gas.
10. Quartz is a type of piezoelectric crystal.
11. Quartz is made of silicon dioxide.
12. The lattice structure of quartz contains polar bonds.
13. The bonds between oxygen and silicon in quartz are not even.
14. The oxygen atoms in quartz are slightly negatively charged.
15. The silicon atoms in quartz are slightly positively charged.
16. When a crystal of quartz is compressed, the negative charges shift in one direction and the positive charges shift in the other.
17. The compression of quartz creates a build-up of positive and negative charge at the faces of the crystal.
18. The build-up of charge can produce a voltage across the faces of the crystal.
19. Any crystal can be piezoelectric if it fulfills certain criteria.
20. The lattice of a piezoelectric crystal must contain polar bonds.
21. The crystal must have a certain type of symmetry or lack of symmetry.
22. Quartz does not have point symmetry.
23. The piezoelectric effect can be used as a sensor.
24. The piezoelectric effect can be used to produce sound.
25. The piezoelectric effect is reversible.
26. A piezoelectric crystal can deform when a voltage is applied across it.
27. The quartz crystal in a quartz watch vibrates 32,768 times per second.