Unit 9 Blog Post #2

In class today we talked talked more about unit 9. The new vocabulary we learned was reflection, refraction, and dispersion. Reflection is the bouncing waves and refraction is the bending of waves. Dispersion is when waves spread out. To show these terms in real life, Mr. Blake drew out ocean waves. He showed how waves can spread out or bend. Another term we went over is natural  frequency, which is the frequency an object wants to vibrate at. An example is when Mr. Blake drops a meter stick, it makes a sound. The sound it makes is based on its size and mass. Sound is its natural frequency. We also talked about Resonance. Resonance is the increase in amplitude of oscillation of an electric or mechanical system exposed to a periodic external force whose frequency is equal to or some multiple of the natural frequency of the system. The big new topic we talked about is sound. Sound is a mechanical wave traveling through a medium. Sound is a longitudinal wave that needs medium to travel. All frequencies of sound travels at the same speed at the same temperature. Solids travels fastest through solids, next liquids, then gases, last it doesn't travel through no medium. We also learned about sound ranges. We talked about how it goes infra sonic to ultra sonic. We can't here that because the human's ear is 20 to 20 hertz.

This is a photo of a surf spot I usually go to. This picture relates to the lesson because we talked about waves. Sometimes in the water there will be times when the waves die down and the water becomes flat. But if you wait a couple minutes, the waves come back. This is like the term dispersion because the waves in the water are spreading out having different times between each wave.