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Archive – Q2  week 9 – 19-20

Week of 1/13 – 1/17
1/13 – Monday – period 2 – 
 
1.Last Ideal gas demonstration – liquid Oxygen from liquid nitrogen
 
2. Rate of reaction demonstration 
        1) Radio/voltaic cells
 
        2) Liquid O2
 
3. Discussion on the Cathode ray experiment  and Subatomic particles determination:
 
               7 Up was created by Charles Leiper Grigg, who launched his St. Louis–based company The Howdy Corporation in 1920. Grigg came up with the formula for a lemon-lime soft drink in 1929. The product, originally named “Bib-Label Lithiated Lemon-Lime Soda”, was launched two weeks before the Wall Street Crash of 1929. It contained lithium citrate, a mood-stabilizing drug, until 1948. It was one of a number of patent medicine products popular in the late-19th and early-20th centuries. Its name was later shortened to “7 Up Lithiated Lemon Soda” before being further shortened to just “7 Up” by 1936.   Source Wikipedia
Lithium citrate is used to treat and prevent episodes of mania in people with bipolar disorder (manic depressive disorder). Lithium is in a class of medications called antimanic agents, which work by decreasing abnormal activity in the brain. As citrate it is prepared as a solution and syrup with 300 mg/5 mL, equivalent to amount of lithium in lithium carbonate.  As the medical community became aware of the pharmaceutical properties of the lithium citrate, it became a FDA controlled substance and it was taken out as an ingredient of 7up.
 
lithium citrate (Li3C6H5O7):
 
 
 
                                                                             Why was this soda called 7up?
 
4. Isotopes/weighted average.
                        period 3/4 – 
 
1.Last Ideal gas demonstration – liquid Oxygen from liquid nitrogen
 
2. Rate of reaction demonstration 
        1) Radio/voltaic cells
 
        2) Liquid O2
 
3. Discussion on the Cathode ray experiment  and Subatomic particles determination:
4. Isotopes/weighted average.
 
5. Balloon Lab
Today’s Demos:
 
Oxygen is a Real Gas as is gets condensed by liquid nitrogen due to oxygen’s boiling point/condensation temperature being higher than liquid nitrogen.

 

Rate of reaction is increased with increasing amount of collisions with a higher density of O2 delivered in the liquid state than in the gaseous state (20% of air).  This is what was supposed to happen!!!
Another Rate of reaction Demo:
 
           
1/13 – Monday Homework – 
 
1.  Determination of subatomic particles from periodic table.  Please complete the following worksheet and review with the key. In the chance that you are rusty with theses skills please use the link below to review this skill.
 
Atomic Structure 2 – subatomic particles.pdf
View Download
 
Atomic Structure 2 – subatomic particles Key.pdf
View Download
 
 
 
2. The Ultraviolet Catastrophe – due Friday morning!
Complete the Ultraviolet Catastrophe Form using the media below.
 
You may need to click on this icon to see the videos to allow the scripts if in Chrome:
 
Ultraviolet Catastrophe Form:
 

Grodski Lecture: (part of lecture) 0:00 – 8:01 (video will only play selected regions)

 
 
Grodski Lecture: (part of lecture) watch 0:00 – 8:01 (for those who cannot see the video above)
 
PBS Digital Studios (part of video)  2:56 – 15:15 (video will only play selected regions)
 
PBS Digital Studios (part of video)  watch only 2:56 – 15:15 (for those who cannot see video above)

 

Figure 1:
Grodski Wave Demo:
 
 
Article for question 10:

Planck’s Solution to the Ultraviolet Catastrophe

The Ultraviolet Catastrophe

When an object such as the filament in a light globe is heated (but not burned) it glows with different colours: black, red, yellow, blue-white, as it gets hotter. To understand how radiation is emitted for all bodies and how the radiation varies with temperature, creative experiments involving the behaviour of standard objects called ‘black bodies’ were being performed in the 1890s. Physicists of the time engaged in such experiments to assist in their understanding of light. A black body is one that absorbs and re-emits all radiation that falls onto its surface. The use of black bodies was necessary because all objects behave slightly differently in terms of the radiation they absrorb and emit at different temperatures. Scientists were using standard black bodies in experiments to study the nature of radiation emitted at different temperatures.

Typical emitted radiation curves for black body radiation at different
temperatures.

As an example of an object used to model a black body, imagine you drilled a very small hole through the wall of an induction furnace (an efficient oven in which the temperature can be set to known values). At a temperature of 1000°C for example, the walls of such a model black body will emit all types of radiation, including visible light and infrared and ultra-violet radiation, but they will not be able to escape the furnace except through the small hole. They will be forced to bounce around in the furnace cavity until the walls of the furnace absorb them. As the walls absorb the radiation they increase in energy. As such, the walls to release radiation of a different wavelength, eventually establishing an equilibrium situation. The walls absorb all radiation applied to the black body, so the radiation leaving the hole in the side of the furnace is characteristic of the equilibrium temperature that exists in the furnace cavity. This emitted radiation is given the name black body radiation. As the graph on the right shows, the radiation emitted from a black body extends over all wavelengths of the EM spectrum. However, the relative intensity varies considerably and is characteristic of a specific temperature. Black bodies absorb all radiation that falls on them and that energy is spread throughout the object. At higher equilibrium temperatures, the emission of more intense, shorter wavelength radiation from the cavity occurs.

A comparison of the experimental results from black bodies compared
with the theoretical predictions that cause the ultraviolet catastrophe.

Physicists used a spectrometer to measure how much light of each colour, or wavelength, was emitted from the hole in the side of the black body models they constructed. The shape of the radiation versus intensity curves on the graphs that they created presented a problem for the physicists attempting to explain the intensity and wavelength variations that occurred quantitatively. The problem was how to explain the results theoretically using classical wave theory. The traditional mathematics based on thermodynamics and classical wave theory predicted that the pattern of radiation should be different to that which the physicists found occurred. The classical wave theory of light predicted that, as the wavelength of the radiation emitted becomes shorter, the energy it carries would increase. In fact, it would increase without limit. This would mean that, as the energy (that was emitted from the walls of the black body and then re-absorbed) decreased in wavelength from the visible into the ultraviolet portion of the spectrum, energy of the radiation emitted from the hole in the black body would approach infinity. This increase in energy would violate the principle of conservation of energy and could not be explained by existing theories. This effect was called the ultraviolet catastrophe. The experimental data from black body experiments indicated that the radiation intensity curve corresponding to a given temperature has a definite peak, passing through a maximum and then declining. This experimental data could not be explained using classical physics, hence the catastrophe.

Planck’s Solution to the Ultraviolet Catastrophe

Max Planck pulls a quantum rabbit out
of a hat.

In 1900, Max Planck, a German physicist, came up with a solution to the ultraviolet catastrophe which ascribed particle status to EM radiation. In the quantum equivalent of pulling a rabbit out of a hat, he showed that an accurate equation for the spectrum could be derived as long as one new assumption was added to those of classical physics. He assumed that the oscillators in the walls of the black body that emit the electromagnetic radiation can only have discrete energies. Each oscillator can have zero energy or some multiple of a fixed amount (quantum) which depends on the frequency, f, of oscillation according to the formula, E=nhf, where n is an integer such as 1, 2, 3, etc., and h is a new constant
(6.626 x 10-34 Js) now known as Planck’s constant.

How does this fix the ultraviolet catastrophe? The shorter wavelengths correspond to higher frequencies, so the oscillators responsible for radiation in this part of the spectrum need a lot more energy even to get into the first vibration state than those emitting radiation at a lower wavelength (lower frequency). Thermal energy is randomly distributed, so the chance that high-frequency oscillators will get enough energy to start vibrating (at least hf) is much less likely than for lower frequency oscillators. The result is that if energy is quantised in this way, the high frequency oscillators are ‘switched off’ and the intensity of the spectrum at high frequencies drops rapidly down to zero – exactly as observed by experiment.

According to Planck’s theory, an oscillating charge in the walls of a black body can only have a certain specific or discrete values for frequency. The energy it produces will be proportional to the frequency with which it is oscillating and, therefore, the energy it produces as a result of the oscillation will also be in discrete packets or quanta. In classical physics remember that all frequencies of oscillation would have been excited and the cumulative effect was the ultraviolet catastrophe. The quanta are not the same size for all colours. They are tiny for infrared, small for green and big for ultraviolet. Consider the furnace again with the energy traffic inside being emitted from the small hole in the side. The quantum restriction will make itself felt at the ultraviolet end of the spectrum where the quanta are big. Infrared will continue to pour out in a copious stream of tiny quanta, too tiny and too continuous to modify the traffic. Ultraviolet light must be emitted in big quanta or not at all. Blue, violet, and above all, ultraviolet will be seriously limited and the ultraviolet catastrophe averted.

Equation – Photon Energy
E = hf

E

f

f

energy carries by a photon

frequency

Planck’s constant

joules (J)

hertz (Hz)

6.626 x 10-34 Js

You should use this equation when calculating the energy carried by an individual photon.

If your head is about to explode then think of it like this. Planck suggested that radiation was emitted from the walls of a black body in discrete energy packets rather than the continuous stream of energy carried by a wave. The thermal equivalent of being blasted with tiny balls of energy from your heater rather than a continuous flow of warmth. In addition, Planck suggested that these energy packets couldn’t have any and every value for energy. The energy packets were discrete in that they could only carry energy that was a whole number integer multiple of hf or their frequency. This was the birth of quantum physics!

Planck changed the picture of radiation from a smooth stream like the wind to a grainy stream like like a sand blast. Planck and other physicists were uneasy about this new idea but there seemed to be no other way to explain the black body spectrum. The inescapable conclusion was that electromagnetic radiation is emitted in discrete energy packets or quanta rather than a smooth wave like everyone thought.

http://www.quarkology.com/12-physics/94-ideas-implementation/94B-PE-effect.html

 

From our reference tables:
 
 
 
There is just not enough energy present at fixed temperatures to elicit high frequency radiation because the oscillators (electrons and atomic nuclei) are taking in the energy in constant chunks (photons) and re-emitting these photons. The energy is not a constant flow and does not build up. 
 
The heater in the Black Body radiator makes the atoms vibrates at all different frequencies and thus a wide range of photons are released because temperature is proportional to molecular motion range.
 
 The lower energy vibrations use up the energy first, leaving very few chunks or quanta to excite  the higher energy vibrations.  The higher energy vibrations (at the smallest wavelengths) are needed to elicit higher frequency radiation and there is just not enough of these photons available.
 
With classical physics, energy is a continuous stream of energy, and oscillators in the black bodies can vibrate with ANY frequency thus have an infinite amount possible frequencies or modes. Classical physics suggests that kinetic energy that is absorbed is absorbed evenly throughout every possible mode (or frequency ). This is called the Equal Partition Theorem and this theory work very well in many cases to predict kinetic energy in many systems.  It did NOT do very well in the explanation of wavelengths emitted from black bodies. Its formulas (of equal partition called the Rayleigh Law) led us with predictions that led to the “catastrophe” because energy that was absorbed by the black body was absorbed equally by all modes of vibration. Because there are more vibrational modes that are smaller (limit to zero) these high frequency modes would gain more of the energy than the less frequent lower frequency modes. 
 

Max Plank’s new formula was able to predict the experimental results IF the frequency which is proportional to the Energy ONLY existed in discreet bundles and was not continuous! That is matter in the black bodies could not vibrate at any frequency and absorb ANY amount of energy. They could only absorb certain energy amounts AND only start vibrating or oscillating at certain frequencies!
 
Max Plank started the quantum revolution!
 
                                                                                 E (energy) =     h     *         f
                                                                        Energy                 =  Planks   *    frequency
                                                                                                                                           Constant
 
    Planks Constant represents a proportionality constant (price per seat!) or the  smallest divisible                                         value that frequency (can have). 
 
                                       It represents the “energy chunk” = 6.63 x 10-34 J s (Joule seconds)
 
                                      Energy is absorbed in chunks of this small value x the frequency of the oscillator.
 
                                                                The oscillator of course are the atoms!!!
 
End Of Monday!

1/14 – Tuesday – period 2/3
1. Complete the Cathode Ray Form
 
2. CRT Demo
3.  Hot Air Balloon construction – Please be careful not to disturb other classes tissue paper and balloons. Please return caps on glue sticks!! I found 2 glue sticks with no caps yesterday on the floor.  You can gently place your hot air balloon over the computer monitors in the lab stations if you balloon is drying or cannot be folded up.
 
Classwork Form:
                               period 3
 
1. Complete the Cathode Ray Form
 
2. CRT Demo
 
Today’s Demo:
The CRT TV and the Magnet:
 
1/14 – Tuesday – Homework –  
 
1.  Ultraviolet Catastrophe – homework due Friday morning
 
2: Please complete the front side of on the front side of Atomic structure 2 – bohrs.pdf worksheet only.
3. Review with key or lecture below.
 
Atomic structure 2 – bohrs.pdf
View Download
 
atomic structure 2 – Bohr Key p.pdf
View Download
 
Lecture on atomic structure 2  – Bohrs worksheet – (front side):
Tonights homework equations that are in our reference tables:
End of Tuesday..

1/15 – Wednesday – period 2
 
Review Weekend Form (Mass spectrometers)
Review CRT Form (yesterday)
Cathode rays = m/charge except in the lecture it was charge to mass ratio
Cathode rays always the same no matter the gas used but the canal ray were different!
Cathode rays produces X-rays and its principle were used in the first TV’s.
The canal rays in the CRT was the first mass spectrometer.

 

In 1913, as part of his exploration into the composition of canal raysJ. J. Thomson channeled a stream of ionized neon through a magnetic and an electric field and measured its deflection by placing a photographic plate in its path. Thomson observed two patches of light on the photographic plate (see image on left), which suggested two different parabolas of deflection. Thomson concluded that the neon gas was composed of atoms of two different atomic masses (neon-20 and neon-22).

Thomson’s student Francis William Aston continued the research at the Cavendish Laboratory in Cambridge, building the first full functional mass spectrometer that was reported in 1919.[7] He was able to identify isotopes of chlorine (35 and 37), bromine (79 and 81), and krypton (78, 80, 82, 83, 84 and 86), proving that these natural occurring elements are composed of a combination of isotopes.

Wikipedia

The idea for mass spectrometer was born from the canal rays in the Cathode Ray Tube (CRT).

Mr. Grodski

1.   Continue 5 Major Experiments of subatomic particles
                   
                       G(r)eeks —-> Dalton ————–> J.J Thompson – cathode ray experiment – 
 
                             Atomos                Modern atomic Theory         Electron (corpuscle) -first subatomic particle
                                                                                                 mass to charge ratio
 
2. GAS LAW TEST RETURNED!
                                    period 3/4
 
Review Weekend Form (Mass spectrometers)
Review CRT Form (yesterday)
 CRT Demo
 
1.  Review 5 Major Experiments of subatomic particles
                   
         G(r)eeks —-> Dalton ————–> J.J Thompson – cathode ray experiment –  Millikin Oil Drop
 
            Atomos                Modern atomic Theory         Electron (corpuscle) -first subatomic particle  –    Charge of electron
                                                                                                      mass to charge ratio of electron                        Avogadro’s number
2, GAS LAW TEST GIVEN BACK 
3.  Balloon Lab
 
 
1/15 – Wednesday –Homework:
 
1. Please review your handed back Gas Law test with the linked key that will be mailed to you.
2. Please complete questions 1 , 2, 3 of the atomic structure – 1 – photoelectric effect.pdf worksheet. Do not complete any questions that uses the photoelectric effect concept. Please view the lecture below that reviews these concepts and introduces the Photoelectric Effect.
 
atomic structure – 1 – photoelectric effect.pdf
View Download
 
atomic structure – 1 – photoelectric effect KEY.pdf
View Download
3. Lecture that review first side of atomic structure – 1 – photoelectric effect worksheet.
Just questions 1,2, and 3 only!
View from 0:00 – 22:30
 
End of Wednesday!

1/16 Thursday – period  2/3
*Handed back atomic experiment Form for students to add notes to..
1. Continue Atomic Experiments, Millikin’s Oil Drop—>Rutherford (started)—->Moseley—->Chadwick
 
2.  Beginning of Quantum mechanics – Ultraviolet Catastrophe – Max Plank
      Birth of the wavelength/frequency/Energy equations
 
3. Balloon Lab
 
                              period 4 – 
 
*Handed back atomic experiment Form for students to add notes to..
 
1. Complete Atomic Experiments, Millikin’s Oil Drop—> (started)Rutherford—->Moseley—->Chadwick
1/16 Thursday – Homework:
1. Complete the Ultraviolet Catastrophe form that is due tomorrow! It was posted Monday procrastinators!
End of Thursday..

1/17 Friday – period 2
 
(started yesterday)Rutherford—->Moseley—->Chadwick
 
Avogadros Number from Milikins..
 
1.   – Beginning of Quantum mechanics – Ultraviolet Catastrophe – Max Plank
      Birth of the wavelength/frequency/Energy equations
2.  Photoelectric Effect
                         period 3/4
 
(started yesterday)Rutherford—->Moseley—->Chadwick
 
Complete – Radioactive particles of Rutherford.
Avogadros Number from Milikins..
 
1.   – Beginning of Quantum mechanics – Ultraviolet Catastrophe – Max Plank
      Birth of the wavelength/frequency/Energy equations
2.  Photoelectric Effect
 
3. Balloon Lab
 
Atomic Structure 1 – Presentation

Atomic Structure 2 – Presentation

1/17 Friday night homework: THIS IS THE UPDATED HOMEWORK!
1.  Complete the photoelectric effect worksheet (side 1 and 2) and review with the key or use the videos posted below to review.  If you need a review of the concept of the photoelectric effect, there is a lecture posted below for your viewing pleasure. I know that I originally said that I would not have you do the Photoelectric effect homework but I changed my mind!
 
I will review Ultraviolet Catastrophe and the Photoelectric Effect in class Tuesday!
 
2. Clash of the TITANS – movie note taking – (instructions below)
You already have these worksheet as you completed question 1,2,3 this week!
atomic structure – 1 – photoelectric effect.pdf
View Download
 
atomic structure – 1 – photoelectric effect KEY.pdf
View Download
Lecture that review first side of atomic structure – 1 – photoelectric effect worksheet.
 
 
Lecture that reviews second side (questions 5 and 6):
Lecture on the Photoelectric effect concepts:

Clash of the Titans:

 Timeline activity – from 00:00 – 27:35 only this weekend!
 
1: Please make a timeline of important events that lead to the 
   development of quantum mechanics (our current model of the atom).
   
Time line activity – Trace the important moments in the development of the atom.
Scientists – dates – places – accomplishments – anecdotes – 
This will be collected once it is completed and YOU ARE ONLY STARTING it!
 
I am asking that you start your timeline from 00:00 to 27:35 of the Clash of the TITANS movie below.
 
I will be collecting this once we complete the entire timeline next week!
 
I have an example posted below which you should model the rest of your Timeline from.
 
Clash of the Titans
Sorry but this one will have Spanish subtitles..
 
or
https://www.youtube.com/watch?v=Y-AiqCp7Vlc
NO subtitles!!!
 
My Example:
 

 

End of week 8!