What / Who / How

Dear Sir/Mdm,

3 Qs to ask you:

1. What/Who created light?
2. How does glow stick work?
3. How stored energy in wind, lakes and reservoirs can be converted into electricity?

For the first query, may I clarify if you meant how light is created? If so, according to The World Book Encyclopedia, "all light comes from atoms. It is produced by atoms that have gained energy either by absorbing light from another source or by being struck by other particles". An atom with extra energy is said to be excited, and visible light is created when electrons within atoms in an excited state returns to a ground state (lower energy configuration).
However, if you meant to ask who created light, then the answer who have to be God (as made clear in the book of Genesis in the bible). Thomas Edison invented the light bulb.

Here are some books you may wish to refer to on light:

Title Light & sight / Jon Richards.
Author Richards, Jon, 1970-
Other Title Light and sight
Publisher New York : PowerKids Press, 2008
Call no.: J 535.078 RIC

Title Amazing light / Sally Hewitt.
Author Hewitt, Sally, 1949-
Publisher New York, NY : Crabtree Pub., c2008
Call no.: J 535 HEW

Title Exploring light / Carol Ballard.
Author Ballard, Carol.
Publisher New York : PowerKids Press, 2008
Call no.: J 535 BAL

Title Light, dark / by Julie Murray.
Author Murray, Julie, 1969-
Publisher Edina, Minn. : ABDO Pub. Co., c2007
Call no.: J P 535 MUR

You can check the availability of the above titles by opening your browser to this url: http://vistaweb.nlb.gov.sg.

For your second query, glow or light sticks use the same principle of light creation as mentioned in the answer to your first query, only that it makes use of chemicals to excite the atoms in a material. According to HowStuffWorks.com, the chemical reaction in a light stick usually involves several steps. A typical commercial light stick holds a hydrogen peroxide solution and a solution containing a phenyl oxalate ester and a fluorescent dye. The sequence of events when the two solutions are combined are as such:

1. The hydrogen peroxide oxidizes the phenyl oxalate ester, resulting in a chemical called phenol and an unstable peroxyacid ester.
2. The unstable peroxyacid ester decomposes, resulting in additional phenol and a cyclic peroxy compound.
3. The cyclic peroxy compound decomposes to carbon dioxide.
4. This decomposition releases energy to the dye.
5. The electrons in the dye atoms jump to a higher level, then fall back down, releasing energy in the form of light.
(source: http://science.howstuffworks.com/light-stick1.htm)

As for how the bending of the glow sticks causes the glow stick to 'glow', there is a smaller thinner vial within each glow stick that, when broken, releases the hydrogen peroxide solution it contains which then mixes with the phenyl oxalate ester and fluorescent dye. This causes a reaction which in turn causes the atoms to begin emitting light.

For your third query, you asked about wind and hydro-electric power. Windmills capture the kinetic energy in wind by making use of turbine blades. When these turbine blades start moving, they spin a shaft which leads from the hub of the rotor to a generator. The generator turns that rotational energy into electricity. The same occurs for water dams. When water is released from a dam, it flows through hydraulic turbines, producing electric power that is used in homes and industries.

In essence, generating electricity from wind and water is about transferring energy from one medium to another. The following books will provide a more in depth look into the subject:

Title Water power / Ian F. Mahaney.
Author Mahaney, Ian F.
Publisher New York, N.Y. : PowerKids Press, 2007.
Call no.: J 333.91 MAH

Title Generating wind power / written by Niki Walker.
Author Walker, Niki, 1972-
Publisher New York, NY : Crabtree Pub., 2007.
Call no.: J 621.4 WAL

Title Save energy / Kay Barnham.
Author Barnham, Kay.
Publisher New York, NY : Crabtree Pub., 2008.
Call no.: J 333.79 BAR

Title Future energy / Julie Richards.
Author Richards, Julie.
Publisher South Yarra, Vic. : Macmillan Education, 2007.
Call no.: J 333.7 RIC

Title The pros and cons of water power / Richard and Louise Spilsbury.
Author Spilsbury, Richard, 1963-
Publisher New York : Rosen Central, 2008.
Call no.: Y 333.914 SPI

Title Hydroelectric power / by Josepha Sherman ; consultant, Steve Brick.
Author Sherman, Josepha.
Publisher Mankato, Minn. : Capstone Press, c2004.
Call no.: J 333.91 SHE

We hope that the above has been useful to you. Please do not hesitate to contact us if you need further assistance.

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