In class on Wednesday, we learned about the development of the Atomic Theory.
First of all, everyone must know that in the olden times, philosophers and scientists could just claim their theories and people would have to believe them. As times when on, scientific data and evidence started being used. Dalton was the first philosopher to use data to support his atomic theory.
John Dalton (Late 1700)
-The atom were tiny, indivisible, and indestructible particles
-Each atom had its own individualistic properties to determine which element it was
-Each element was different because of their different masses
At Dalton's time period, it was amazing that a scientist had used proof and data to back up their theory. Although it was not exactly the correct idea, he had made a great discovery for his times. Then, a scientist named J.J Thomson came and discovered more about the atom. Between the time of Dalton and Thomson, electricity and magnetism had been discovered.
J.J. Thomson (1897)
Through the cathode ray experiment (a vacuum tube with all air expelled from it), he created the plum-pudding model of the atom.
-There were positive charges throughout the atom.
-Electrons were floating around in the cloud of positive charge
-Particles have to balance each other out.
Here's a video explaining the cathode ray experiment.
After Thomson came Ernest Rutherford who conducted the gold foil experiment to also improve the atomic theory. Rutherford was a student of Thomson and wanted to prove his mentor's model, but then ended up discovering his own model.
Ernest Rutherford (1871-1937)
-Discovered the nucleus
-The nucleus had small dense positive charge
This is a video of how Rutherford found this model.
Through this experiment he found the nucleus, but do not confuse this with the fact that he discovered the proton and neutrons, because he did not.
Around the end of class, we learned a little bit about Waves and forms of energy. The speed of light equals wavelengths times frequency. ( λν = c, λ=wavelengths, ν=frequency, c=speed of light)
Visible colors to the naked human eye are only a small portion on the electromagnetic spectrum.
-The shorter the wavelength, the higher the frequency which is more dangerous to us humans. (towards the gamma ray end)
-The longer the wavelength, the lower the frequency. Generally, these pass right through humans and are not dangerous. (towards the radio end)
-On the frequency bar, the colorful rainbow in the middle is the place where frequencies can be seen by humans.
In class, Mr. Lieberman did an awesome demonstration with glow in the dark paper and a purple laser pointer. Unfortunately, it was too dark to tape and I don't think anyone would've appreciated flash. Plus, it might have cancelled the effect of the demo. In any case, here's a similar situation of what Mr. Lieberman did.
He did this with a red, green, and purple laser pointer. Purple worked best, though, because purple is on the end with shorter wavelengths.
Hope this all made sense to everyone. Sorry about being late on this post again.
The next scribe will be Courtney Smith. Good luck!!! ^.^
