POWER

Electromagnetic Spectrum

 

Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves, to very short gamma rays. 

The photon is the basic unit of electromagnetic radiation energy...the shorter the wavelength, the higher the energy. A wavelength  is the distance between crests (tops) of a wave. Wavelengths look like a squiggly line. The Frequency of a wavelength is the number of crests that pass a given point within one second. This is also called a Hertz (Hz).

 

Just like at Woodstock in 1969, the shorter the concert was,  the more energy everyone had! With a shorter period of time that the bands would be playing, the audience was allowed to release more energy while dancing and singing. It's as if the shorter the concert, the louder it was just like how if you have a shorter wavelength, you have a higher energy!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The pigments in plants (what gives the plant their color) are colored because they absorb some wavelengths more than others. Chlorophyll in plants typically absorb wavelengths of 680 nm to 700 nm, yet visible light is between 400 nm and 700 nm. As said before, the 400nm is a shorter wavelength so it will have a higher energy! 

 

A Spectrophotometer measures a pigment's ability to absorb various wavelengths. The machine sends light through pigments and measures the fraction of light transmitted at each wavelength. 

 

Chlorophyll a is the main photosynthetic pigment in plants, especially in the flowers woven through flower childrens hair. 

There are other types of photosynthetic pigments other thzn chlorophyll a, though! Chlorophyll b can be present. They broaden the spectrum used for a photo. Carotenoids are another type of photosynthetic pigment. They can absorb excessive light that has the ability to damage chlorophyll. 

 

Just like there are different types of photosynthetic pigments in plants, there are also several different types of people who attended the Woodstock concert! It was not only Flower Children, there were also Hippies, wealthy citizens, and poor citizens. Each type of person who attended the Woodstock concert brought about something different to the experience, just like Chlorophyll a, b and Carotenoids all have a different job during photosynthesis. 

 

When pigments absorb light, they go from a ground state to an excited state which is unstable just like how when drugs were taken at Woodstock by the concert goers they would go from a stable relaxed state, to a more excited and unstable state. Sun is the main source of energy across the spectrum. Mechanical waves and electromagnetic waves are two important ways energy is transported in the world, such as waves in water and sound waves. 

 

Remember, energy cannot be created or destroyed. When light is absorbed by a green plant, a small portion of that energy is converted into chemical energy in the process of photosynthesis. 

 

There are two different types of experiments that reveal what wavelengths work best for photosynthesis. The absorption spectrum is when a light is being shined through a purified pigment. The action spectrum is when a plant is illuminated with different wavelengths. The action spectrum was first demonstrated in 1883 by Theodor W. Engelmann. In his experiment, he exposed different segments of a filamentous alga to different wavelengths. Areas receiving wavelengths favorable to photosynthesis produced excess O2. He used the growth of aerobic bacteria clustered along the alga as a measure of O2 production.