PhET-Simulations-for-Biology/C3/Radioactive-Dating-game/English-timed

Time	Narration
00:01	Welcome to this tutorial on Radioactive Dating Game, an interactive PhET simulation.
00:08	In this tutorial, we will demonstrate, Radioactive Dating Game, an interactive PhET simulation.
00:17	Here I am using, Ubuntu Linux OS version 16.04 Java version 1.8.0 Firefox Web Browser version 60.0.2
00:32	Learners should be familiar with high school physics and chemistry.
00:37	Using this simulation, we will look at Radioactive decay and half life Decay rates Measurement of radioactivity Radioactive dating
00:51	Please refer to the additional material provided with this tutorial.
00:55	Let us begin.
00:58	Use the given link to download the simulation.
01:02	I have already downloaded the Radioactive Dating Game simulation to my Downloads folder.
01:10	To open the jar file, open the terminal.
01:14	At the terminal prompt, type cd Downloads and press Enter.
01:22	Type java space hyphen jar space radioactive-dating-game underscore en dot jar, press Enter.
01:36	File opens in the browser in html format.
01:41	This is the interface for the Radioactive Dating Game simulation.
01:46	Now we will explore the interface.
01:49	The interface has four screens: Half Life Decay Rates Measurement Dating Game
02:00	We are already looking at the Half Life screen.
02:04	At the top of the screen is an Isotope versus Time graph.
02:09	Pay attention to the units of time.
02:12	On the right side of the screen, you see a Choose Isotope panel.
02:17	It has three options showing unstable nucleus decaying to stable nucleus.
02:25	In the middle is the simulation panel containing a Bucket o’ Atoms.
02:31	Note that it contains C-14 atoms as the default selection is C-14.
02:38	Attached to the bottom of the bucket is a button called “Add 10”.
02:44	Stable and Unstable Nuclei The strong nuclear force overcomes the electrostatic repulsion between protons.
02:54	The energy associated with this force is the binding energy.
03:00	The lower the binding energy, the more unstable is the nucleus.
03:06	Such an unstable nucleus is said to be radioactive.
03:12	Below the simulation panel is a Play/Pause button and a Step button next to it.
03:19	In the simulation panel is a blue Reset All Nuclei button.
03:25	It lets you return to the start but with the selected isotope.
03:30	Below the right panel is a white Reset All button.
03:35	It resets the simulation in this screen to all the default settings.
03:41	Observe the Isotope versus time graph.
03:45	There is a vertical red dashed line labeled Half Life near the 5000 year mark.
03:52	The half-life of C-14 is 5730 years.
03:58	Along the y-axis, you can see the red C-14 symbol above the blue N-14 symbol.
04:06	C-14 atoms will appear in the upper row and N-14 atoms in the lower one.
04:13	To the left of the Isotope label is a red circle.
04:17	Numbers of C-14 and N-14 atoms shown by hash symbols will appear to the left of the circle.
04:26	Radioactive Decay Radioactive Decay is the spontaneous conversion of an unstable nucleus into a stable nucleus.
04:36	It involves the release of subatomic particles and their energy as radiation.
04:43	It is of the following types: Alpha decay Beta decay Gamma decay.
04:52	Half-life is the time taken for half of the nuclei in a radioactive material to decay.
05:01	Let us get back to the simulation.
05:04	Click on Add 10 and immediately click on the Pause button.
05:10	Ten C-14 atoms have been added to the simulation panel.
05:15	Almost immediately, red C-14 has started to decay to give blue N-14.
05:22	Observe the atoms moving across the graph in the two rows.
05:28	Note how the circle changes to blue as more N-14 atoms form.
05:34	Keep clicking on Step button to the right of Pause.
05:42	The circle is half red and half blue.
05:47	Observe that there are 5 blue N-14 atoms in the graph.
05:54	There are 5 C-14 atoms and 5 N-14 atoms in the simulation panel also.
06:01	This is the definition of half-life.
06:04	If you click again on Add 10, another 10 C-14 atoms will be added to the simulation panel.
06:12	Predict the number of C-14 atoms remaining after different periods.
06:18	Perform the same simulation for the other nuclei.
06:23	Click on the Decay Rates tab to go to that screen.
06:28	The interface has a similar arrangement as the Half Life screen.
06:33	Please explore this screen in the same way.
06:37	Now, let us click on the Measurement tab to go to that screen.
06:42	In the right panel, under Choose an Object, we will stay with Tree, the default selection.
06:50	In the top left, under Probe Type, we will retain the default selections, Carbon-14 and Objects.
06:59	In the bottom right corner, click on Plant Tree button.
07:04	Immediately click on the Pause button.
07:07	Observe 100% appear above Probe Type in the upper left corner.
07:14	Keep clicking on the Step button to the right of Pause to move the simulation along.
07:23	Above the graph, % of C-14 is the default selection.
07:29	The white box below the graph shows the number of years since the tree was planted.
07:35	The red line shows % of C-14 remaining in the tree.
07:41	Click on the second C-14 to C-12 ratio radio button above the graph.
07:48	Now the red line shows the C-14 to C-12 ratio in the tree.
07:53	Click again on the % of C-14 radio button above the graph.
07:58	Keep track of the % in the top left, the tree and the number of years below the graph.
08:09	Note down the number of years and % of C-14 when the tree Loses its green color Loses all its leaves Falls over.
08:20	Click on the Play or Step buttons to get approximately 50% in the top left window.
08:35	Note the number of years after which you see 50% of C-14 in the tree.
08:42	Click on Rock and Uranium-238 radio buttons.
08:50	Click on Erupt Volcano and Cool rock buttons.
08:58	Measure U-238 levels in the cooled volcanic rock.
09:04	Click on the Air radio button to compare isotope levels in objects to air levels.
09:12	Let us click on the last Dating Game tab to go to that screen.
09:17	We can measure levels of C-14, U-238 or other custom nuclei in this screen.
09:25	We see objects on and below the ground on which we can place the probe to measure these levels.
09:34	Radioactive Dating Carbon has two isotopes: C-12 and C-14.
09:41	Both are converted to carbon dioxide and are taken in by living organisms.
09:47	When an organism dies, it no longer takes in any carbon. So levels of C-14 and ratio of C-14 to C-12 fall.
09:57	Radioactive Dating-Continued Radioactive dating compares C-14 C-12 ratio of samples to recently dead specimens.
10:06	It estimates how long the organism has been dead.
10:10	Uranium-lead dating is used for rocks, archaeological artefacts etc.
10:17	On the top, we see the graph like the ones in the previous screens.
10:22	Let us keep the following default selections: Under Probe Type, Carbon-14 Objects % of C-14
10:33	We will drag the probe and place it on the animal skull on the ground, to the left.
10:40	Observe a pop-up box that appears next to the skull.
10:45	We see the text, “Estimate age of Animal Skull” and “years” next to the empty box below.
10:53	Below this is a Check Estimate button.
10:57	Observe that in the top left side, above Probe Type, we see 98.2%.
11:04	Let us drag the double-headed green arrow above the graph.
11:09	In the white box above the arrow, % of C-14 should be approximately 98.2%.
11:18	Observe that t equals 123 yrs appears in the white box above the graph.
11:26	Type 123 in the empty box below Estimate age of Animal Skull.
11:33	Click Check Estimate button.
11:36	The Estimate pop-up box disappears.
11:40	A green text-box with 123 years appears in its place with a green smiley face next to it.
11:48	We have successfully dated the animal skull by measuring the % of C-14 remaining in it.
11:56	As an assignment, Estimate ages of all the objects in the Dating Game screen.
12:03	Correlate age in years with percentage of unstable nucleus.
12:08	Correlate age in years with the depth at which the object is found.
12:13	Remember to use C-14 for animal remains and U-238 for rocks and other objects.
12:20	Let us summarize.
12:22	In this tutorial, we have demonstrated how to use the Radioactive Dating Game PhET simulation.
12:31	Using this simulation, we looked at: Radioactive decay and half life Decay rates Measurement of radioactivity Radioactive dating
12:46	The video at the following link summarizes the Spoken Tutorial project.
12:52	Please download and watch it.
12:55	The Spoken Tutorial Project team conducts workshops using spoken tutorials and gives certificates on passing online tests.
13:04	For more details, please write to us.
13:08	Please post your timed queries in this forum.
13:12	This project is partially funded by Pandit Madan Mohan Malaviya National Mission on Teachers and Teaching.
13:20	Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.
13:28	More information on this mission is available at this link.
13:33	This is Vidhya Iyer from IIT Bombay, signing off.
13:37	Thank you for joining.

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