Ernest Rutherford
Vocabulary:
Alpha/positive (helium4 nucleus) beta/negative (electrons) gamma rays
Proton Daughter atom Neutron Half life
Charge-charge repulsion
Start with a “this was the way they thought of it at the time” (for example right now we don’t think anything can travel faster than the speed of light), about a uniformly charge distribution (both positive and negative) in the atom.
Then display the three button video with no sound:
http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/ruther14.swf
Students observe these results and postulate explanations for the behavior of the alpha particles.
Student Questions:
Why do some of the atoms pass directly through the gold foil?
What does the angle of deflection mean?
For a secondary tool they can visit these two sites, the first is interactive and allows them to shoot alpha particles at a nucleus and the second is a continuous stream that allows them to watch alpha particles bombard the nuclei of gold foil:
http://www.waowen.screaming.net/revision/nuclear/rsanim.htm
http://micro.magnet.fsu.edu/electromag/java/rutherford/
Alpha/positive (helium4 nucleus) beta/negative (electrons) gamma rays
Proton Daughter atom Neutron Half life
Charge-charge repulsion
Start with a “this was the way they thought of it at the time” (for example right now we don’t think anything can travel faster than the speed of light), about a uniformly charge distribution (both positive and negative) in the atom.
Then display the three button video with no sound:
http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/ruther14.swf
Students observe these results and postulate explanations for the behavior of the alpha particles.
Student Questions:
Why do some of the atoms pass directly through the gold foil?
What does the angle of deflection mean?
For a secondary tool they can visit these two sites, the first is interactive and allows them to shoot alpha particles at a nucleus and the second is a continuous stream that allows them to watch alpha particles bombard the nuclei of gold foil:
http://www.waowen.screaming.net/revision/nuclear/rsanim.htm
http://micro.magnet.fsu.edu/electromag/java/rutherford/