Students started Orbit of Mars lab.
Many got off to a slow start since I told them they had to read the instructions (instead of me telling them what to do) so I told them they could work on the lab tomorrow in class.
Tuesday, November 30, 2010
Monday, November 29, 2010
Monday, Nov 29, 2010
Asked if there were any demos for rotational inertia.
TW brought in different diameter jars. He was going to fill them with equal masses of water and see which rolled faster down a ramp. I asked if he had tried racing them without water and he said the speeds were pretty much the same.
To test this we tried racing pennies and quarters. Didn't work well since they kept falling over. Used u-tack to stick 4 of each together and raced them. Not completely clear, but they were pretty close.
Started Hewitt video on Gravity.
Stopped for:
a. discussion of "Universal" and how it changed the world view
b. Did several examples using Newton's Law for finding the force with varying masses and distances. Showed how to do the substitution math.
c. How different dimension worlds would affect the Intensity vs distance relationship
d. Students calculated G*Me/Re^2
Postponed HW (Kepler's Law worksheet) until tomorrow.
TW brought in different diameter jars. He was going to fill them with equal masses of water and see which rolled faster down a ramp. I asked if he had tried racing them without water and he said the speeds were pretty much the same.
To test this we tried racing pennies and quarters. Didn't work well since they kept falling over. Used u-tack to stick 4 of each together and raced them. Not completely clear, but they were pretty close.
Started Hewitt video on Gravity.
Stopped for:
a. discussion of "Universal" and how it changed the world view
b. Did several examples using Newton's Law for finding the force with varying masses and distances. Showed how to do the substitution math.
c. How different dimension worlds would affect the Intensity vs distance relationship
d. Students calculated G*Me/Re^2
Postponed HW (Kepler's Law worksheet) until tomorrow.
Sunday, November 21, 2010
Wednesday, Nov 24, 2010
Competition of balancing pencil
Gave each person one pencil, 3 sheets of newspaper, and 6 inches of tape. They had to make a device that they could balance on their finger without touching the newspaper.
Had competition in groups of 4, then did winners.
Asked students to write this up in their journals.
Showed parts of Hewitt video on Rotation - especially the two examples in the introduction. Offered extra credit for best demonstration of rotational inertia for falling rods.
No homework over Thanksgiving holiday.
Gave each person one pencil, 3 sheets of newspaper, and 6 inches of tape. They had to make a device that they could balance on their finger without touching the newspaper.
Had competition in groups of 4, then did winners.
Asked students to write this up in their journals.
Showed parts of Hewitt video on Rotation - especially the two examples in the introduction. Offered extra credit for best demonstration of rotational inertia for falling rods.
No homework over Thanksgiving holiday.
Monday, Nov 22, 2010
Go over results from Circular Motion Lab
Collect Lab Reports
Derive circular motion equation from octagons
Show examples of centripetal force
Jumped ahead and introduced Newton's Law of Gravitation, showed it was a centripetal force, and did example of problems of docking spaceships in orbit about the Earth.
Collect Lab Reports
Derive circular motion equation from octagons
Show examples of centripetal force
Jumped ahead and introduced Newton's Law of Gravitation, showed it was a centripetal force, and did example of problems of docking spaceships in orbit about the Earth.
Friday, November 19, 2010
Thursday, November 18, 2010
Thursday, Nov 18, 2010
Had students cut out shapes and find the center of mass of their shape.
Showed Hewitt video on Center of Gravity.
Showed broom example.
Showed top and spinning cross from Saturday Market.
Students tried to spin pennies on coat hangers.
Showed Hewitt video on Center of Gravity.
Showed broom example.
Showed top and spinning cross from Saturday Market.
Students tried to spin pennies on coat hangers.
Wednesday, November 17, 2010
Wednesday, Nov 17, 2010
Went over RA 11.1 on torque
Many students either did not do the book problems or did not understand them.
Had students go to the board and work them.
Center of Gravity demos:
1. Stand up from being seated in chair
2. Stand two footsteps back from wall, put forehead on wall, try to pick up chair.
3. Stand with toes against wall, try to stand on toes
4. Balancing hammer
5. Balancing eagle
6. Belt demo
7. Angled ramp, double cone falls up ramp
8. Block competition
Showed people who were absent how spool of science works.
Many students either did not do the book problems or did not understand them.
Had students go to the board and work them.
Center of Gravity demos:
1. Stand up from being seated in chair
2. Stand two footsteps back from wall, put forehead on wall, try to pick up chair.
3. Stand with toes against wall, try to stand on toes
4. Balancing hammer
5. Balancing eagle
6. Belt demo
7. Angled ramp, double cone falls up ramp
8. Block competition
Showed people who were absent how spool of science works.
Tuesday, November 16, 2010
Tuesday, Nov 16, 2010
Went over demos from yesterday.
Talked about effect of melting ice cap and sediment discharge from Mississippi River on length of day.
Meter stick balances at center of mass.
Torque lecture
Demo: giant spool
Did several simple torque problems on board.
Handed out RA 11.1 on torque, due tomorrow along with problems from end of chapter 11.
Talked about effect of melting ice cap and sediment discharge from Mississippi River on length of day.
Meter stick balances at center of mass.
Torque lecture
Demo: giant spool
Did several simple torque problems on board.
Handed out RA 11.1 on torque, due tomorrow along with problems from end of chapter 11.
Monday, November 15, 2010
Monday, November 15, 2010
Handed back tests and went over any questions. Numbers on test are percent out of 100 and number correct out of 43. In my gradebook I scaled the test scores and entered them out of 70
Handed back journals. The maximum score was 60 but I put them out of 50 in my gradebook. I talked about the journals. The main purpose is to have a description of the demos and how they relate to the concepts. Several students are just using the journal as a notebook and ignoring the demos all together. I asked for more focus on the demos for this quarter.
Angular equivalents to linear terms:
velocity <=> angular velocity (omega)
inertia (mass) <=> rotational inertia (I)
momentum (p=m*v) <=> angular momentum = I * omega
kinetic energy = 1/2 m * v2 <=> rotational KE = 1/2 I omega2
Day at the Races
Demos: Baseball bat and ankle weights
Race 1: Hoop vs Disc
Race 2: Plastic disks with ball bearings inside
Race 3: Shiny ball vs Go Car
Race 4: Broth vs Beans
Students voted on outcomes
Conservation of momentum <=> conservation of angular momentum
If no net external torque acts on the system (if nothing messes with the system from outside) then there is no change in the angular momentum of the system.
Demo: weights on spinning plate
Handed out RA 11.2 due tomorrow
Students will also write up demos in their journals
Finished with bicycle wheel on spinning platform and then gyroscopic bicycle wheel.
Handed back journals. The maximum score was 60 but I put them out of 50 in my gradebook. I talked about the journals. The main purpose is to have a description of the demos and how they relate to the concepts. Several students are just using the journal as a notebook and ignoring the demos all together. I asked for more focus on the demos for this quarter.
Angular equivalents to linear terms:
velocity <=> angular velocity (omega)
inertia (mass) <=> rotational inertia (I)
momentum (p=m*v) <=> angular momentum = I * omega
kinetic energy = 1/2 m * v2 <=> rotational KE = 1/2 I omega2
Day at the Races
Demos: Baseball bat and ankle weights
Race 1: Hoop vs Disc
Race 2: Plastic disks with ball bearings inside
Race 3: Shiny ball vs Go Car
Race 4: Broth vs Beans
Students voted on outcomes
Conservation of momentum <=> conservation of angular momentum
If no net external torque acts on the system (if nothing messes with the system from outside) then there is no change in the angular momentum of the system.
Demo: weights on spinning plate
Handed out RA 11.2 due tomorrow
Students will also write up demos in their journals
Finished with bicycle wheel on spinning platform and then gyroscopic bicycle wheel.
Subscribe to:
Comments (Atom)