Revision as of 16:33, 11 May 2008

Outcomes

Student should be able to describe and compare the Plum Pudding model and the Rutherford model of the atom.
Students should recall that like charges repel.
Using the observations from the Geiger and Marsden’s experiment they should be able to make conclusions about the structure of the atom and how they support the Rutherford model.

7.15 Describe the results of Geiger and Marsden’s experiments with gold foil and alpha particles
7.16 Describe Rutherford’s nuclear model of the atom and how it accounts for the results of Geiger and Marsden’s experiment and understand the factors (charge and speed) which affect the deflection of alpha particles by a nucleus.

Help student recall that like charges repel and unlike charges attract.
Teacher must state that the alpha particles are positively charged.
Use the 'Plum pudding model box' and the 'Rutherford model box' to simulate the experiment. Start with the ‘dilute positive sphere' in the 'Plum pudding model box', explaining that this is what they expected to see and then move onto the 'Rutherford model box'. These should be done undercover, the boxes should not be lifted. Students should only observe the results.
Emphasise the observations as a class and then split them into groups and using the observations and conclusions sheet they could try to draw a conclusion on the structure of the atom.

Write a dialogue between two people explaining the plum pudding and Rutherford models, the Geiger and Marsden’s Experiment and how their observations led to the new model of the atom.

One Ramp
Set of metal balls
One Rutherford model and one ‘dilute positive charge’ drawn on a piece of paper with two boxes to go over top. Boxes must have slits along base to allow ball to travel through.

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 ==Main Body of Lesson==
-* Use the Rutherford model to simulate the experiment.  Start with ‘dilute positive sphere’ and then add the nucleus after. This should be done undercover (in a box) Students should only observe the result.
+* Help student recall that like charges repel and unlike charges attract.
 * Teacher must state that the alpha particles are positively charged.
+* Use the 'Plum pudding model box' and the 'Rutherford model box' to simulate the experiment.  Start with the ‘dilute positive sphere' in the 'Plum pudding model box', explaining that this is what they expected to see and then move onto the 'Rutherford model box'. These should be done undercover, the boxes should not be lifted. Students should only observe the results.
 * Emphasise the observations as a class and then split them into groups and using the [[observations and conclusions sheet]] they could try to draw a conclusion on the structure of the atom.