September 17 (Monday) Sonic Ranger Day 1
If you missed today: The Einstein Board
1. Hand out sketch a graph and do 2 of the 6 with class, assigning the remaining 4 for Thursday.
2. Hand out Graphs of Motion 2 worksheet and do 1 or 2 in class and read a possible story for number 3 as an example. Assign: 1-4 for Wednesday.
3. Reflexes - Trying to catch a dollar bill by pinching it as a friend drops it between your fingers. (Something to do on a date list)
4. Show some of the past Graph Your Route labs. Note all 10 Physic classes on the back bulletin board.
5. Time to work in your groups on the Measurement Lab.
We collected the sketch-a-graph homework on Friday of this week but we finished it in class today. Here is the blank sketch-a-graph and here is the sketch-a-graph key so you can grade it and fix anything you had wrong. Due on Thursday of this week.
Acceleration of Gravity is -9.8 m/s/s
To show how fast gravity was I dropped a dollar bill vertically between the open pinched fingers of a student each period. I said, "Are you ready...are you sure...?" and randomly let the dollar bill go and they tried pinching their fingers together as it dropped full length between their fingers. (Note: Add to something to do on a date or baby sitting). Then I handed out plastic 30 cm long rulers to each table and had each student try to catch the ruler falling between their pinched fingers then looking it what the ruler spot was their pinched fingers caught it at. If it was more than 15 cm, they had no change in catching the dollar bill. Some students were able to catch the bill, half the time or more than half the time (great reflexes).
The Big Pictures:
1. From the sketch-a-graph homework sheet due Thursday
a. the slope of a line on a distance time graph gives the instantaneous speed.
b. the slope of a line on a velocity time graph gives the instantaneous acceleration.
So a horizontal line on a distance/time graph means stopped whereas on a velocity/time graph means a constant velocity.
A diagonal line on a distance/time graph means constant speed whereas on a velocity/time graph means a constant acceleration.
c. The acceleration/time graphs look like a carved pumpkin with teeth. You are either acc. or not. All the stopped or constant velocities are at zero acc. and a +acc. will be a tooth of the pumpkin up and a -acc. will be a tooth down.
2. From the Graphs of Motion sheet 1-4 due Wed. and 5-6 due Thursday.
2. The acceleration of gravity will cause a dollar bill to drop so fast that you cannot react in time to pinch your fingers before it slips between them.
a. the slope of a line on a distance time graph gives the instantaneous speed.
b. the slope of a line on a velocity time graph gives the instantaneous acceleration.
So a horizontal line on a distance/time graph means stopped whereas on a velocity/time graph means a constant velocity.
A diagonal line on a distance/time graph means constant speed whereas on a velocity/time graph means a constant acceleration.
c. The acceleration/time graphs look like a carved pumpkin with teeth. You are either acc. or not. All the stopped or constant velocities are at zero acc. and a +acc. will be a tooth of the pumpkin up and a -acc. will be a tooth down.
2. From the Graphs of Motion sheet 1-4 due Wed. and 5-6 due Thursday.
2. The acceleration of gravity will cause a dollar bill to drop so fast that you cannot react in time to pinch your fingers before it slips between them.