Transcript Research Experience for Teachers 2002

Research Experience for
Teachers
LIGO 2002
John R. Thacker
Covington High School
Summer in Livingston !
Gaining culture
Demonstrations
LIGO Experiences
Lesson Plan Ideas
Data Analysis
Culture: it’s surprising
where Gravity turns up…
Kokomo - The Beach Boys
“To Martinique,
that Monserrat
mystique
We'll put out to
sea
And we'll perfect
our chemistry
By and by we'll
defy a little bit of
gravity …”
Meetings . . .
Clean Rooms . . .
Laser Safety . . .
SURF Lectures . . .
Control Room . . .
Culture
PEPI Installation
Easy does it . . .
Hmmnn. . . . . . . . .
LIGO Experience
Lesson Plan Ideas
Temperature v. Distance
Incandescent source
Sensor: thermistor
Using Data Collection System
Schematic for MAX187 ADC
Switch Box Close Up
The Detector
4000
Initial Start Up
thermistor voltage (mV)
3500
3000
2500
2000
-60.000000000
1500
0.000000000
60.000000000
120.000000000
Elapsed Time (sec)
180.000000000
240.000000000
300.0000000
Thermistor Volts v. Time
4000
Thermistor Volts (mV)
3500
1.5 in. displ.
2.5 in. displ
3000
3.5 in. displ
4.5 in. displ
5.5 in. displ
6.5 in. displ
2500
7.5 in. displ
8.5 in. displ
2000
1500
0.0
100.0
200.0
300.0
Elapsed time (s)
400.0
500.0
600.0
Thermistor Voltage (mV) v. Distance from Incandescent Source
Thermistor Voltage (mV)
4000
3500
3000
2500
2000
1500
1000
500
0
0
2
4
6
8
10
Distance from Incandescent Source (in.)
12
14
So, what were the results ?
Temperature decreases by
one over the cube root of the
distance { y = 3461 X (- 0.31) }
Beyond about 8 inches
temperature data was marginal
Thermistor required about 3
minutes to stabilize
Lesson Plan Ideas
Using a Thermistor to Monitor
Power Consumed
Thermistor
Output Voltage
to ADC
Variable DC
Input ( 2 VDC
to 22 VDC )
Input
Voltage to
Thermistor 5 VDC
200 Ohm Power
Resistor with
Thermistor Attached
Resistor Voltage 10 VDC
1500
Thermistor Voltage (mV)
1480
Typical Thermistor
Voltage V. Time Curve
1460
1440
1420
1400
1380
About 6 minutes to stabilize
1360
9:14:24
9:15:50
9:17:17
9:18:43
9:20:10
9:21:36
Local Time
9:23:02
9:24:29
9:25:55
9:27:22
Resistance (kilo ohms) V. Temperature (deg C)
350
Thermistor Resistance (k ohms)
300
Curve based on
manufacturer data
supplied with
Thermistor
250
200
150
100
NTC: Negative
Thermal Constant
50
0
-60
-40
-20
0
20
40
Temperature (deg C)
60
80
100
120
So, what were the results ?
Voltage thru power resistor varied: 2 – 22 VDC
Current thru power resistor calculated : I = V/R
Power Consumed: P = I V
Graph Power Consumed v. Thermistor voltage
Power Consumed v. Thermistor Volts
2.5
Power Consumed (W)
2
1.5
1
0.5
0
0
0.2
0.4
0.6
0.8
1
Thermistor Voltage (V)
1.2
1.4
1.6
1.
Results:
For our limited range of
voltage input, the results are
essentially linear;
The results are not
expected to be linear for
larger voltage values input to
the power resistor;
Meteor Search
Look for Sudden Enhancements to Atmosphere
(SEAs) caused by meteor induced ionization trail
Meteor Scatter – uses ionization trails to reflect
radio waves
Trails are typically 80 – 100 km high
Used day or
communications
night
–
even
for
“secure”
Meteor Search – HOW ?
Tune to “empty” frequency in VHF
band (41 – 68 MHz) & wait for reception of
a distant transmitting station
Typical reflections last 1 to 10 seconds
Geometric Optics
Ionization Trail
Geometric
optics
Solar Flare Search
20 – 100 kHZ band
Look for enhanced signals
flare heavily ionizes
ionosphere down to D layer
VLF wave guide ducting
occurs – more efficient
propagati
Pinewood Derby Racetrack
Demonstrate Energy Put into the System
Positive and Negative Curvature
Connection to Gravity
Demonstrations
The first 16 ft of the 24 ft track
Prototype of Starting Block
Demonstrations
It works !
A Peak Inside . . .
Jam Nuts, Anyone ??
Simplify . . .
The Test Vehicles
Integrated Mass
Units
Don’t leave home without it . . .
Which One Wins ??
They’re Off ! !
Are the results what you expected ?
Switching lanes . . .
Just another pretty face
It doesn’t matter which lane
you choose . . .
Analyzing LIGO Data
Ext Air Temp (deg F) 7/14/02
95
90
85
deg F
80
75
70
65
60
55
50
0
120
240
360
480
600
720
840
elapsed time (min)
960
1080
1200
1320
1440
Classroom Data Analysis
31.5
31
Soil Temps 7/13 - 7/14 2002
30.5
Temp (deg C)
30
29.5
29
28.5
28
27.5
27
26.5
26
-60
40
140
240
340
440
540
640
740
Data Points
840
940
1040
1140
1240
1340
1440