Using the CPO timer All of the items below should be in the “Little Black Box of Science”
-
Upload
gwendoline-thompson -
Category
Documents
-
view
213 -
download
0
Transcript of Using the CPO timer All of the items below should be in the “Little Black Box of Science”
Using the CPO timer
• All of the items below should be in the“Little Black Box of Science”
CPO Timer Inputs• It doesn’t make a difference what color (red or
blue) phone cord you use for input A or B.• However, the A cord/photogate should be the top
photogate.
CPO Computer
Photogateuses an invisible beam of infra-red
light to start and stop the timer.
The 5.0 cm car “wing” triggers the Photogate
The 5.0 cm wing start and stops the timer
The timer works like 3 internal stopwatchs
Time thru A
Time thru B
Time from A to B
No times shown
Using the CPO Timer
• Turn on the A light only, if you want to know how long it took the car to go through photogate A.
• Turn on the B light only, if you want to know how long it took the car to go through photogate B.
• Turn on the A & B lights, if you want to know how long it took the car to go from photogate A through photogate B.
Using the CPO Timer
• On interval mode, you never have to push the reset button. It automatically resets every time you send the car down.
• The timer “remembers” all 3 times when you send the car down the ramp. To retrieve the times, just push the corresponding A & B buttons.
Resolution
• The smallest interval that can be measured.
The timer has a resolution of (.0001 seconds)
That’s ten thousandth’s of a second
Interval Mode
Tenth Hundredth ThousandthTen Thousandth
Accuracy• Accuracy: how close a measurement is to the true
value.
The CPO Timer & Photogates are accurate to the + or - .0005 of a
second.
Precision: How close together repeated
measurements are.• Which group is more precise?
Group A (s)
Group B
(s)
.0238 .1487
.0296 .1482
.0201 .1479
.0193 .1485
.0333 .1483
“IFR”Index Finger Release
• This will make a big difference on the precision of our data!• Good “IFR” technique should give us a precision
of + or - .0005 seconds
Accuracy & Precision