Tuesday, May 3, 2011

Solar Power

   Solar Power is the conversion of sunlight into energy. It either directly photovoltaics (PV) or indirectly using concentrated solar power (CSP). CSP uses lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. PV converts light into electric current by using the photoelectric effect.

Friday, April 1, 2011

Rainbow Glasses

How do Rainbow Glasses work?
They have special lenses that bend and separate light into the colors of the spectrum

What does it teach?
Light consists of "waves" that can be seen as color when bent or separated by a prism.

Wednesday, February 23, 2011

Loudnessss !


Sound loudness is a subjective term describing the strength of the ear's perception of a sound. It is related to sound intensity, but can't be considered identical to intensity. Sound intensity is the power per unit area.

Environmental Noise
Weakest sound heard0dB
Whisper Quiet Library30dB
Normal conversation (3-5')60-70dB
Telephone dial tone80dB
City Traffic (inside car)85dB
Train whistle at 500', Truck Traffic90dB
Subway train at 200'95dB
Level at which sustained exposure may result in hearing loss90 - 95dB
Power mower at 3'107dB
Snowmobile, Motorcycle100dB
Power saw at 3'110dB
Sandblasting, Loud Rock Concert115dB
Pain begins125dB
Pneumatic riveter at 4'125dB
Even short term exposure can cause permanent damage - Loudest recommended exposure WITHhearing protection140dB
Jet engine at 100', Gun Blast140dB
Death of hearing tissue180dB
Loudest sound possible194dB

Long time exposer to these loud decibels can cause ear and brain damage. For example, 110 Decibels Regular exposure of more than 1 minute risks permanent hearing loss.


Frequency is the number of occurrences of a repeating event per unit time. Frequency f is the reciprocal of the time T taken to complete one cycle (the period). In wave motion, it is the number of waves that pass through a given point per second.

File:Sine waves different frequencies.svg

In this picture, the red is the lowest frequency because the waves are spread farther apart while the purple is the highest frequency because the waves are closer together. 


My Singing Voice -


Tuning Fork

1.) .0097 2.) .0127 3.) .0162 4.) .0191 5.) .0221 6.) .0257 7.) .0286
7 waves/.0189 per second = 370.4

Different animals hear different frequencies than humans. Elephants can hear lower frequencies, while dolphins can hear louder. The range they hear in is called infra sound, because infra means lower. They can hear lower than human hearing.

Tuesday, February 22, 2011

Sound Crossword

3. connection from signal source
4. Pressure Level (SPL) the loudness of an acoustic wave stated in dB that is proportional to the logarithm of its intensity.
6. a unit of electrical power
8. the length of a sound wave in air
9. number of occurrences of a repeated event per unit time
11. an electrical circuit designed to increase the current or voltage of an applied signal
13. a sensation perceived by sense of hearing
16. The relative magnitude of a signal
1. The quality of a sound related to its harmonic structure.
2. a loudspeaker designed to reproduce bass frequencies
5. the part of a dynamic loudspeaker attached to the voice coil that moves and produces the sound
7. (highs) the upper end of the audio spectrum reproduced by tweeters, usually 3 - 4 kHz and up
10. a complete path that allows electrical current from one terminal of a voltage source to the other terminal
12. a loudspeaker transducer designed to reproduce low-frequency sounds
14. (E) a unit of measurement used to measure how much "pressure" is used to force electricity through a circuit
15. The low end of the audio frequency spectrum between 0Hz to about 200 Hz

Monday, January 31, 2011

Parallel and Series Circuits

   A Series Circuit has more than one resistor, or something that uses electricity. It gets its name from having only one path for the charges to move along. The resistors share the same amount of electrons, but split voltage. They equally get the same amount of voltage. If a resistor is broken then no charge will be able to go through because there is no alternative route. Old christmas lights are series circuits because if one bulb goes out, the whole string won't work. 

   A Parallel circuit differs from a Series. Unlike the series circuit, it has multiple paths for the electrons to travel along. The electrons have a choice to go through any of the paths. In a parallel circuit, electrons split up and choose the "path of least resistance". They share the same voltage. Parallel circuits are found most homes. This is so when you turn something off everything doesn't go off. 

   A current carrying conductor generates a magnetic field. When hen this is then placed in an external magnetic field, it will experience a force proportional to the current in the conductor, and to the strength of the external magnetic field. As you are well aware of from playing with magnets as a kid, opposite (North and South) polarities attract, while like polarities (North and North, South and South) repel. The internal configuration of a DC motor is designed to harness the magnetic interaction between a current-carrying conductor and an external magnetic field to generate rotational motion.