Using Speakers and Making Sounds

In 1876 an engineer named Bell obtained a patent for a device that could transmit understandable voice sounds over a wire.  Bell was one of many scientists, technologists, engineers and  mathematicians who develop the speakers we use today.

Speakers come in a variety of physical sizes and shapes.  The power of the speaker is measured in watts ( Unit W ).  One watt is calculated as an electrical source of 1 volt supplying 1 amp of electrical current.  It is called a  "derived" unit, since you calculate it by measuring voltage and amperage.

Please read this week's Tasks and Activities.

  • Here is picture of two different speakers used in the class
  • The wattage of the speaker does not always measure their "loudness".
  • Hi fidelity ( Hifi ) speakers may cost $100
  • The speakers shown here cost less than $1
  • The black stranded wire connects to the negative terminal of the battery
  • OR the white strand is connected to th +ve terminal
  • Making sounds, such as music, pulls the cone of the speaker backwards and forwards.
  • We hear the sound with movement of the air between the speaker and our ears.
  • This image shows how a project will require an amplifier module attached to speakers.
  • The amplifier should match the power rating of the speakers.
  • The loudness of the speakers may be changed by software or hardware controls.

 

Tasks and Activities

  1. Go to one of the work stations set up around the room. Touch the negative wire of the speaker to the negative terminal of the battery.  What do you notice?
  2. How can you tell that the speakers in the classroom contain magnets?
  3. How is the wattage of a speaker "derived"?
  4. Does your project require sound?  Will you need to attach an amplifier to make the sound louder?
  5. Why are some speakers more expensive than others?

 

  

Don't forget to email your choices/answers to Mr. Widmer by the end of this week.  Keep a copy of that email in your Google Docs folder.