Overview
Let’s take a break from all of the “book learning” and explore the world around you. For these assignments, your writing will be focused on Everyday Physics which will help you connect your Readings to things that have happened in the world around you.
In this module, you will look for an article or news story/video that relates to one or more of the following topics:
Special relativity
Photons
These are pretty broad topics, but a few ideas should spring readily to mind.
Create a thread with a post including one or more of the topics listed above, an active hyperlink to your resource (this resource cannot be used by another student), a summary of the resource itself, a summary of the material you are learning in this module as it relates to your resource (cite portions of the textbook), and an explanation of how the topic or resource ties to your everyday life.
Then provide a substantive reply to at least two of your classmates’ posts before the end of the module. Don’t forget to reply to the comments your classmates leave about your original post, too.
The History of Our Understanding of Light and the Photoelectric Effect
https://www.symmetrymagazine.org/article/what-is-a-photon?language_content_entity=undLinks to an external site.
https://unacademy.com/content/neet-ug/study-material/physics/the-uses-and-effects-of-photoelectric-effect/#:~:text=Ans.-,The%20photoelectric%20effect%20occurs%20due%20to%20the%20striking%20of%20light,solar%20panels%20to%20generate%20electricity.Links to an external site.
Light is a fundamental part of our universe. As far as we know, it is vital to life but despite this, it was a long and interesting journey to understand what light actually is. Really, what we "know" now isn't a fact as all science is theory-based and can neither be proven nor disproven, but you get my point.
Since Isaac Newton performed his glass prism experiment, light was believed to behave as a particle. There was still significant debate about whether this particle model of light worked best or not to define light, as shining light through a small hole/ slit would cause the light to spread out like a wave. Around the same time, Christiaan Huygens published a paper that declared light as a wave. The consensus for the next 200 years flipped back and forth between people "proving" that light behaved as a wave to that of a particle. It wasn't until the early 1900s when our boy, Albert Einstein, put his foot down and used the photoelectric effect to posthumously award both of the scientific pioneers as being correct. That is, light behaves as both a particle and a wave. The photoelectric effect is essentially when lightwaves above a certain frequency pry electrons from metal it is shone on. If light behaved only as a wave, any frequency of light would pry an electron off eventually as it would build up over time and reach the required energy to bonk the electron off. Since only light above a certain frequency actually dislodged the electrons, though, this is proof that light travels in particles as well, named photons. Today, the photoelectric effect is used most commonly in solar panels to generate electricity.
Second post
The Photoelectric Effect and UV sensors
Hello class, this week I will be covering the photoelectric effect applied to ultraviolet sensors. Before we apply the photoelectric effect to our daily lives, we need to define it first. Our textbook on page 1228 explains that the photoelectric effect occurs when "you direct a beam of light of short enough wavelength onto a clean metal surface, the light will cause electrons to leave that surface (the light will eject the electrons from the surface).
Ultraviolet sensors also known as ultraviolet photosensitive tubes take advantage of the photoelectric effect. Ultraviolet sensors can be used to detect UV rays that may be undetectable to the human body and human senses. Ultraviolet sensors are commonly used to assist with detecting flames and flameout protection. Also, UV sensors can be also used in smoke detectors. Photoelectric smoke detectors aim a beam of light into a chamber. When smoke enters the chamber light reflects back onto the sensor. When light is reflected back onto the sensor an alarm inside of the smoke detector is triggered. The photoelectric effect can be used to prevent excess harm to people by helping to alert people at the start of an emergency. UV photoelectric sensors are also reliable and may last up to a decade or even longer if they are installed properly. UV photoelectric sensors can become an expensive piece of kit depending on the application. Lastly, there are many different other applications of the photoelectric effect, which include solar panels, cameras, and photocopiers.