Thursday, February 24, 2011


We found the decibels of loudness and different sounds. We found that anything makes sound. Even if it is an empty room, there is still a good amount of sound. We went to the weight room, it was empty and I talked into the sound level meter. It read 95 decibels and I think it was from my voice and the echoing of the empty room. The gym was 69, our stomping feet in the back hall was 79, utility room 74.5, art room 73, wood tech 77.9, vending machine 64, coir singing 70, nutrition room 66, dryer 68.6, running water 73, someone talking quietly was 65, copy machine 63, spanish room 64,h room 63 and me screaming in an empty room was 86. My scream was 86 and talking was in the 70s. Too loud in the classroom in my opinion is in the 80s because that is going to be too distracting for kids to concentrate. I feel the voices would create the sound of 80 decibels and it would be much too loud for kids. I think each classroom should be the in the mid 70s because it would be easier for everyone to concentrate but it would also be a positive learning environment for everyone to participate and hear what is being said. I thought it was interesting that even an empty room had such a high amount of decibels. I thought it would be lower because there was no one talking or making extra sounds. Loudness depends on the environment and extra sounds in the environment. I really liked learning about the sounds and decibels throughout the school.

Tuesday, February 22, 2011


We measured frequency and found the wave of sounds. The crest is the top of the wave and the trough is the bottom. We needed to zoom in on the wave so that we could have a clearer picture and discover the sound more clearly. It was hard to get a good reading every time because not every sound came out clearly and made a nice wave. Zooming in helped to see the wave and find the crest and trough more easily. You take the number of waves divided by the time and get frequency. The frequency I got for the tuning fork was 522 frequency. I got 3125 for the frequncy of the speaking voice, which is too high. I got 869.6 frequency for the singing voice. Low frequency sounds travel better. Frequency is able to be calculated but it is hard to get a good looking sound wave and to find the right frequency.

Thursday, February 17, 2011

Animals and Singers: Hearing and Singing Frequencies

All animals and humans hear and can sing different frequencies, measured in Hertz. Some animals can hear higher pitches than humans. Low frequency sounds travel better.
Humans: 20 Hz-20,000 Hz
Dogs: 40 Hz-60,000 Hz
Bats: 20 Hz-120,000 Hz
Mice: 1 kHz-70 or 90 kHz
Cat: 100 Hz- 60,000 Hz
Elephant: 1 Hz-20,000 Hz
Rat: 1,000 Hz- 90,000 Hz
Noctuid moth: 1,000 Hz- 90,000 Hz
Grasshopper: hear up to 50,000 Hz
Dolphin: hear up to 100,000 Hz
Pigeon: hear as low as .1 Hz
Mice: 40 kHz
Bottlenose dolphins: 0.25 kHz- 150 kHz
Harbour porpoise: 2 kHz- 110 kHz
Soprano: G3 (below middle C4) to F6, above C6 or higher
Altos: low c3 (below middle C4) to high C6 or up to high A6
Tenor: C (octave below middle C) up to a high C, D or above
Bass: low E (or lower) and octave below middle C to E, F, G or above middle C

Wordbank for Crossword


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.
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

Wednesday, February 9, 2011

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.

Tuesday, February 8, 2011

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.