1. Photons 8-11-2018 10 am CST Scientistmel.com Twitter.com/scientistmel
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2. Photons What are they? What do they do? Where can we find them?
How do we use them?

3. Photons What are they? Elementary Particle (also a wave)
Basic Unit of EM – radiation
Coined term by Gilbert Lewis 1926

4. Photons Move at speed of light. Electrically neutral Have no mass
Have energy (not at rest)
Can be created/destroyed
Particle interactions

5. Photons
Photons carry energy based on the distance between waves…the shorter the wavelength, the stronger the energy. This is why certain types of radiation..UV, Gamma, and xray are bad for us. The wavelengths are short and the energy increases.
Photons have no mass, but they do have energy.
Photons can also be created and destroyed. In regard to creation of photons, this happens when something emits EM waves.  In their destruction, they may be absorbed by matter and transfer energy to the atoms and molecules. Creation and destruction of photons must obey the laws of conservation…of both energy and momentum.

6. Photons MATH ALERT!!! Energy (E) = hf = hc/λ f = c/λ λ = wavelength
c = speed of light
h = Planck’s constant

7. Photons E = hf H is Planck’s constant f is the frequency
E = hf = hc/λ.  Here h = 6.626*10-34 Js is a universal constant called Planck's constant.  The energy of each photon is inversely proportional to the wavelength.  The shorter the wavelength, the more energy the photon carries, the longer the wavelength, the less energy the photon carries. Frequency is how many crests of waves that pass over a point in one second.
E = hf
H is Planck’s constant
f is the frequency

8. Photons Kangaroo Science!
If you are still confuzzled about thinking bigger waves should mean more energy…let’s look at kangaroos. Which kangaroo is exerting more energy? The top of course! More waves in a shorter period of time mean more energy.
Kangaroo Science!

9. Photons
Higher frequency = shorter wavelength

10. Photons Little –> High Energy
As we move across the electromagnetic spectrum, we increase the frequency thereby increasing energy. This translates to what we know as microwave, infrared, visible, ultraviolet, xrays, and gamma radiation. We use photon energy in just about everything we do in life as well as in many facets of science.
Little –> High Energy

11. Photons Photoelectric effect Einstein won the Nobel in 1921
Kicking out electrons with light

12. Photons Photoelectric effect EM (light waves) strike a metal
Electron is ejected

13. Photons Not every wavelength works
Velocity = frequency x wavelength
Not every wavelength works
Higher energy photons = faster electrons
Metals have free electrons on surface

14. Scientists use the photo electric effect to determine the composition of samples as well as the concentration of different compounds in a sample. When light from a certain wavelength (for example 280 nm) is shown through a tiny cuvette of a solution, the amount of protein can be determined based on how much light is absorbed by the sample. This is called the absorbance.
Another use for this type of effect is fluorescence and phosphorescence. Electrons get excited to higher energy levels when light is absorbed by a compound. It then emits light when it relaxes. The amount of light emitted can be quantified to determine how much of a compound is in a sample.
Because of the light emitted from other planets, we can also determine what their atmospheres are made of based on the wavelength.

15. Photons
We can get spectral lines through emission and/or absorption

16. Photons Emission on top Absorption on bottom
The spectral lines of a specific element or molecule at rest in a laboratory always occur at the same wavelengths. For this reason, we are able to identify which element or molecule is causing the spectral lines.
Emission on top
Absorption on bottom

17. Photons
If the emitter or absorber atom/molecule is in motion, the position of the spectral lines will be altered via Doppler shift along the spectrum. You can have a redshift or blue shift. A redshift means the lines move to longer wavelengths. Therefore an emitter/absorber moving away from the observer. The blueshift means the lines move to shorter wavelengths. This means motion towards the observer. We can also use redshift and blue shift in determining changes within a solution…for example binding between 2 compounds.

18. Photons
Certain frequencies can affect the atoms in a compound. By moving these atoms around, we can generate a response…this response is what we measure. Here are examples of the type of spectroscopy used to determine what compounds are in a mixture and how much of it is there.

19. Photons Non-ionizing = bonds intact Ionizing = breaks bonds
When we move to higher frequencies and shorter wavelengths, we can destroy compounds by breaking their bonds. This is why gamma radiation is so damaging and how it is that exposure to too many x-rays can cause cancer.
Non-ionizing = bonds intact
Ionizing = breaks bonds

20. Photons Adding size to sight Only “see” things in the visible spectrum
Our eyes are only receptive to a range of wavelengths within this spectrum. The higher frequencies can damage your eyes as they can break bonds and damage DNA. This is why we take measures to be safe in our dealings with EM radiation.
Adding size to sight
Only “see” things in the visible spectrum

21. Photons What are they? What do they do? Where can we find them?
How do we use them?

22. Genealogy Kits Sources!
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25. Photons 8-11-2018 10 am CST Scientistmel.com Twitter.com/scientistmel
Patreon.com/scientistmel
am CST