Wordbank for Crossword

Rarefaction
Wavelength
CarrierMedium
Period
Interference
Octave
Vibration
Resonance
NervePulses
Frequency
Cycles
Pitch
Timbre
ToneQuality
Envelope
Rectangle
Partials
Reverberation
ModeShape
Sound

Across
2. Doubling or halving of a frequency
4. The same vibration will have different wavelengths depending on the_______________
6. Natural frequency associated with a particular pattern of vibration.
8. Sound waves have two phases: compression and ____________________
9. "Color" of the sound.
10. Two waves traveling in the opposite direction
11. Logitudinal mechanical pressure wave with particles traveling toward or away from the source of vibration.
12. How we perceive and interpret frequency.
13. Number of disturbances per second, measured in Hertz
15. Additional frequencies, not harmonic.
Down
1. Stream of continuing sound.
3. Distance between 2 compression or rarefaction cycles.
5. Timbre is ___________ of sound.
7. Shape of a sound.
14. The more _______per unit, the higher the frequency

Speakers and Microphones..How they work

A speaker is made of a magnet, wire coil, and cone shaped diaphragm. An alternating current is generated by the microphone or an amplifier, which flows through the wire coil in the speaker. The current alternates at the same frequency as the sound waves and induces an alternating magnetic field that is in the wire coil. The polarity of the magnetic field alternates and is attracted and repelled by the magnet. The coil then vibrates and causes the diaphragm to vibrate and produce the sounds of the microphone or the amplifier.
Microphones detect sound information and translates it into electric current patterns. Magneto dynamic microphones have thin metal diaphragms and are attached to wire coil. The air vibrations are intercepted by the microphone and transmitted into metal surfaces, which is turned into electrical currents. The speed and motion frequency of the diaphragm are the factors that determine how current is transmitted. These microphones are known as "velocity sensitive."
Microphone sensitivity measures the amount of electrical output produced by a sound. Sensitivity levels have to be high to capture short and low sounds. Microphone overload is when loud sounds overdrive the mic. Diaphragms may be damaged if the coil and magnetic field lose contact. Microphone distortion is when the diaphragm is not aligned correctly and the sounds produced do not come out right.
Speakers and microphones are two different devices, but they use many of the same materials and both create sound.

Speakers...and other things

We have made so many different experiments so far such as, testing batteries, lighting lightbulbs, learning about circuits, generating motors and making speakers. We have learned about parallel circuits which is electricity with multiples for the electricity to travel, and series circuits with one path for electricity to travel and it can use a switch. We also learned that there are 4 different ways to light a lightbulb. The switching of the wires between the positive and negative and then touching the battery to the foot of the lightbulb or the silver, metal ring. We made DC motors and learned about the energy, the magnet and battery that are all connected. Once the wire ring starts moving, the energy from the battery and electrons make it keep spinning. But most recently we have made speakers. We used 2 paper plates, magnets, wire, notecrads, and glue. We wrapped wire and 2 strips of paper around the magnet. We glued it all in place and then pulled the first piece of paper and the magnet out. Glue the magnet to the back of one plate and the wire coil to the back of the other plate. Then make the cards into accordions and glue them to each plate so the plates are glued together. The magnet needs to be sure to slip in and out of the wire coil to create vibrations. The wires need to stick out of the sides of the plates so they can be sanded down so the wires can connect to alligator clips and the amp that plays the music. The magnet, wire and clips all connect together to make the sound and create the speaker.

Scientists and their Influence

Electricity

This week and last week we have been learning about electricity and different circuits. We have practiced on the computer and with hands on projects. We have learned about parallel circuits and series circuits. Parallel circuits have multiple paths for electricty to travel but series circuits have only one path. Series circuits use a switch to turn the lightbulbs on and off.
Series: V=IR (current x resistance= voltage)amps
Parallel: VI=P (voltage x current= power)watts
We also learned about voltemeters which measures the amount of volts in a battery and in a ligtbulb. The total amount of volts in a lightbulb must add up to the total amount of volts in the battery. The computer helped me to understand each circuit. What it would look like and how the voltemeters worked. I also learned that the more battery, the brighter the lightbulbs are. The more lightbulbs but less battery, the lightbulbs get dimmer. We have practiced a lot already and we are still learning more.