PhET/C3/Models-of-the-Hydrogen-Atom/English

Visual Cue	Narration
Slide Number 1 Title slide	Welcome to the spoken tutorial on Models of the hydrogen atom.
Slide Number 2 Learning objectives	In this tutorial we will, Demonstrate Models of the Hydrogen Atom, PhET simulation.
Slide Number 3 System Requirements	Here I am using- Ubuntu Linux OS v 14.04 Java v 1.7.0
Slide Number 4 Pre-requisites	To follow this tutorial, Learner should be familiar with topics in high school science.
Slide Number 5 Learning Goals	Using this simulation we will, Visualize different models of the hydrogen atom. Explain the experimental predictions of each model. Discuss limitations of each model.
Slide Number 6 Learning Goals	Explain the energy level diagram. Determine the orbital shape and orientation from n, l and m values.
	Let us start the demonstration.
Slide Number 7 Link for PhET simulation http://phet.colorado.edu	Use the given link to download the simulation. http://phet.colorado.edu
Point to Models of the Hydrogen Atom.	I have already downloaded Models of the Hydrogen Atom simulation to my Downloads folder.
To open java file, Press Ctrl+Alt+T keys. Type cd Downloads and press Enter.	To run the simulation, open the terminal. At the prompt type cd space Downloads and press Enter.
Type java hyphen jar hydrogen-atom_en.jar and press Enter. Point to the interface.	Then type, java space hyphen jar space hydrogen hyphen atom_en.jar and press Enter. Models of the Hydrogen Atom simulation opens.
Point to File and Help.	Top-left corner of the screen has a menu bar with menu items File and Help.
Point to Experiment and Prediction.	Below the menu bar, there is a grey button with two options, Experiment and Prediction.
Point to Experiment.	By default Experiment mode opens.
Point to light gun.	On the screen, we see an experimental setup with a light gun to emit beam of photons.
Point to Box of Hydrogen. Point to zoom-in box.	There is also a Box of Hydrogen. This box is filled with hydrogen atoms. The zoom-in box represents a single hydrogen atom.
Point to Turn on the gun message.	A message appears. It prompts you to click on the red button to turn on the light beam.
Point to White and Monochromatic radio buttons. Point to White radio button.	The light gun has two light controls, White and Monochromatic. By default White light is selected.
Click on Prediction button. Point to Atomic Model panel. Point to Classical and Quantum Atomic Models.	Click on Prediction option on the grey button. Atomic Model panel opens on the left-side of the screen. It has a list of Classical and Quantum Atomic Models.
Cursor on the interface.	Here we can check how the prediction of a model matches the experimental results.
Point to Legend box.	Legend box on the right-side of the screen has a list of sub-atomic particles.
Point to slider at the bottom. Point to Play/Pause and Step buttons.	At the bottom of the screen we have, Slider to control speed of animation Play/Pause and Step buttons.
Point to Billiard Ball model. Click on Billiard Ball from the list.	The first model of atom proposed is the Billiard Ball model. By default Billiard Ball is selected from the list.
Slide Number 8 Billiard Ball Model	Billiard Ball Model Billiard Ball model is also called as Dalton's atomic model. It was proposed by John Dalton. According to this model, individual atom is visualized as solid, hard spheres, like billiard balls.
Click on the red button of the light gun. Point to White light.	Click on the red button of the light gun. Select White light.
Point to photons in zoom in box.	A beam of photons having different wave lengths pass through box of hydrogen.
Point to deflected photons in the path of hydrogen atom.	Observe that, All photons in the path of hydrogen atoms are deflected.
Slide Number 9 Limitations of Billiard Ball Model Experiments showed that atoms are mostly made up of empty space. Presence of different kinds of sub-atomic particles was also established.	Limitations of Billiard Ball model. Here are the limitations of Billiard Ball model.
Slide Number 10 Limitations of Billiard Ball Model Sub-atomic particles carry positive and negative charges. Based on these observations, Plum Pudding Model was suggested.
Cursor on the interface. Click on the red button of light gun. Click on Plum Pudding model.	Back to the simulation. Turn off the light beam. Click on Plum Pudding from the Atomic Model list.
Point to model in zoom in box. Point to brown mass. Point to blue color particle.	This model was proposed by J. J. Thomson in 1898. The positive charge is uniformly distributed and electrons are embedded into it. The brown mass is the positive charge. Blue color particle in the middle is the electron.
Click on Show spectrometer check-box. Click on the red button of light gun. Select White light.	Click on Show spectrometer check-box. Turn on the light beam. Select White light.
Point to electron and deflected photons. Point to spectrum.	When photons strikes electron, the electron moves and photons deflected. Notice that, spectrum consists of only emitted uv photons.
Click on red button of the spectrometer.	Turn off the light beam.
Slide Number 11 Limitations of Plum Pudding model Gold foil scattering experiments by Rutherford showed that, Positive charge is not spread evenly over the entire atom.	Limitations of Plum Pudding model This model failed because of the following reasons.
Point to Classical solar system model of atom.	Based on the above observations, Rutherford proposed the Classical solar system model of atom.
Slide Number 12 Solar System Model	Solar System Model Rutherford nuclear model of an atom is like a small scale solar system. Nucleus plays the role of sun and the electrons that of revolving planets.
Slide Number 13 Solar System Model	The very small positive charge portion of the atom was called nucleus. Electrons move around the nucleus. They move with very high speed in circular paths called orbits.
Cursor on the interface. Click on Pause button. Click on Classical Solar System.	Back to the simulation. Pause the simulation. Click on Classical Solar System from the list.
Point to Show electron energy level diagram. Click on the check box. Point to Electron energy level diagram.	Screen has Show electron energy level diagram check-box at the top-right corner. Click on the check box. It shows the energy of the electron.
Cursor on the interface.	If this model were true, it should take an electron only a fraction of a second to spiral into the nucleus.
Click on the red button of light gun.	Turn on the light beam.
Drag the speed slider to slow.	Drag the speed slider to slow.
Click on Pause button>>> click Step button.	Click on Step button to view the energy of the electron. Energy of the electron goes from highest to lowest in a fraction of a second.
Cursor on the interface. Click on the red button of light gun.	We know that this does not happen. Atom is known to be stable. Turn off the light beam.
Slide Number 14 Limitations of Solar System model	Limitations of Solar System model Rutherford model cannot explain, The stability of an atom and also, The distribution of electrons and their energies.
Cursor on the interface. Click on Bohr model. Cursor on the interface.	Back to the simulation. From the Atomic Model list, click on Bohr. Neils Bohr proposed a model of hydrogen atom to improve upon Rutherford's model.
Point to electron and orbits in the zoom in box. Point to orbits in the zoom in box. Point to n=1,2,3,4 in the Electron energy level diagram.	According to this model, The electron moves around the nucleus in an orbit of fixed radius and energy. The energy of an electron in the orbit does not change with time. These orbits are called energy levels. These orbits are represented by n=1,2,3,4 etc in the Electron energy level diagram.
Click on the red button of light gun. Click on Play button.	Turn on the light beam. Click on Play button.
Point to electron in the first orbit of atom. Point electron at n =1 in energy level diagram.	Initially there is an electron in the 1st orbit of an atom. Electron energy level diagram shows electron at n =1st level.
Point to Electron energy level diagram. Point to Electron energy level diagram.	Observe the electronic transition in Electron energy level diagram. Electron absorbs photon and gets excited to higher level. Energy is emitted when electron moves from higher level to lower level.
Point to electron in 1st level.	This electron returns back to 1st level.
Point to spectrometer. Point to emitted photons in the spectrometer.	Observe the spectrometer. Spectrometer shows emitted photons.
Click on Monochromatic radiobutton.	Under Light controls, click on Monochromatic radio button.
Check Show absorption wavelengths checkbox.	Then check Show absorption wavelengths checkbox.
Point to four vertical spectral lines.	You will see four vertical spectral lines. These lines represent the wavelengths of absorption.
Point to highlighted slider. Point to 94 nm wavelength in text box.	The slider is highlighted on the first line. Wavelength, 94 nm as shown in the text box.
Point to Electron energy level diagram.	As the photon strikes the electron, observe the electronic transition at 94 nm in Electron energy level diagram.
Point to electron at n= 6 level. Point to electron at n=1 level.	The electron moves to n= 6th level. After a while it moves to lower level by emitting photon.
Click on the red button of light gun.	Turn off the light beam.
Slide Number 15 Assignment	As an assignment, Select Bohr Atomic model. Change the light beam to Monochromatic. Observe the electronic transitions at 103nm, 112nm, and 122 nm absorption wave lengths.
Slide Number 16 Assignment	Observe the energy level diagram and the spectrometer results. Note the observation and give an explanation.
Slide Number 17 Limitations of Bohr’s model The spectrum of atoms other than hydrogen. Finer details of the hydrogen atom spectrum. Ability of atoms to form molecules by chemical bonds. Splitting of spectral lines in the presence of, a Magnetic field (Zeeman effect) or an Electric field (Stark effect).	Limitations of Bohr’s model Bohr's model was unable to explain the following phenomena.
Cursor on the interface. Point to deBroglie Model.	Back to the simulation. Another model based on dual behavior of electrons was proposed.
Click on deBroglie model. Point to wave in zoom in box.	Click on de Broglie from the Atomic Model list. Notice the wave which represents electron in zoom-in box.
Slide Number 18 deBroglie Atomic Model	deBroglie Atomic Model The French physicist, de Broglie in 1924 proposed dual behavior of electrons. Like radiation, matter should also exhibit both particle and wavelike properties. Electrons should also have momentum as well as wavelength.
Click on the red button of light gun.	Turn on the light beam.
Point to electron>>Point to electron at higher energy level orbit. Point to electron at lower energy level orbit. Point to energy level diagram.	Notice that the electron absorbs photon and moves to higher energy level orbit. Electron at higher energy level emits energy. It returns to the lower energy level orbit. Observe the electronic transitions in energy level diagram.
Point to radial view drop-down box. Click on drop-down arrow. Scroll to 3D view>>click on 3D view.	Top-left corner of the view box has radial view drop-down box. Click on drop-down arrow. Scroll to 3D view and click on it.
Point to wave nature of electron in 3D view. Click on the red button of light gun.	Now observe the wave nature of electron in 3D view. Turn off the light beam.
Cursor on the interface.	In order to explain the spectrum of hydrogen atom, theory of quantum mechanics came into existence.
Slide number 19 Schrödinger Model	Schrödinger Model Erwin Schrödinger proposed the quantum mechanical model of the atom. Schrödinger used mathematical equations to describe the probability of finding an electron.
Slide Number 20 Quantum Numbers	Quantum Numbers The three coordinates that come from Schrodinger's wave equations are quantum numbers, Principal (n), Angular (l), and Magnetic (m). Quantum numbers describe size, shape and orientation of the orbitals.
Cursor on the interface. Click on Schrödinger model. Point to atom in the zoom in box.	Back to simulation. Click on Schrödinger from the list. In the zoom in box, atom is shown with nucleus surrounded by electron cloud.
Click on the White radio button.	Switch back to White light.
Click on the red button of light gun.	Turn on the light beam.
Point to electron in zoom in box.	Observe that electron absorbs photon and moves to different orbital.
Point to shapes of orbitals.	Observe the shapes of orbitals as the electron moves.
Point to Electron energy level diagram. Point to n, l, m in energy level diagram.	Notice the electronic transitions in Electron energy level diagram. In addition to value of n, energy level diagram has values for l and m also.
Point to n, l, m value at the bottom right corner of the view box. Point to n, l, m value.	Note n, l, m values at the bottom right corner of the view box. Note the change in n, l, m values as the photons strike the electrons.
Cursor on the interface.	All these models compare how the experimental results match with the prediction.
Slide Number 21 Assignment	As an assignment, For the Schrodinger's atomic model, select Monochromatic light beam. Note n,l,m values for the electron at four absorption wavelengths. Note the orbital shape and possible orientations for each wavelength.
Slide Number 22 Summary	Let us summarise. In this tutorial we have demonstrated, How to use Models of the Hydrogen Atom, PhET simulation.
Slide Number 23 Summary	Using this simulation we have, Visualized different models of the hydrogen atom. Explained the experimental predictions of each model. Discussed limitations of each model.
Slide Number 24 Summary	Determined the orbital shape and orientation from n, l and m values. Explained the energy level diagram.
Slide Number 25 About Spoken Tutorial project	The video at the following link summarizes the Spoken Tutorial project. Please download and watch it.
Slide Number 26 Spoken Tutorial workshops	The Spoken Tutorial Project team: conducts workshops using spoken tutorials and gives certificates on passing online tests. For more details, please write to us.
Slide Number 27 Forum for specific questions: Do you have questions in THIS Spoken Tutorial? Please visit this site Choose the minute and second where you have the question. Explain your question briefly Someone from our team will answer them.	Please post your timed queries in this forum.
Slide Number 28 Acknowledgements	This project is partially funded by Pandit Madan Mohan Malaviya National Mission on Teachers and Teaching.
Slide Number 29 Acknowledgement	Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India. More information on this mission is available at this link.
	This is Meenal Ghoderao from IIT Bombay. Thank you for joining.

Contributors and Content Editors

Karwanjehimanshi95, Meenalghoderao, Snehalathak