# Solar Storms and You!

## Activity 9: A Soda Bottle Magnetometer....Data

This series of measurements was record at the Goddard Space Flight Center between January 25-29, 1999. A centimeter ruler was used, and the readings below are in centimeters. Also, the distance from the mirror to the laser spot being used in this Mark 2 magnetometer was 216 centimeters. This means that a 1 centimeter shift in the spot at this distance corresponds to 0.12 degrees or 7.7 arcminutes. The size of the laser spot is 4 centimeters, and my measurements are based on eyeballing from 2 meters, where the center of the spot is. Generally I can estimate this pretty well, but the accuracy is probably not more than 3-4 millimeters. Assuming this is my systematic measuring error, this corresponds to a roughly 0.3 x 7.7 = 2 arcminute accuracy. I will assume that all of the numbers below have a '1-sigma' uncertainty of +/- 0.3 centimeters. This means that any significant deviation needs to be at least 3 x 0.3 or about 1 centimeter in size before I will get 'excited' about it. Note, 3-sigma corresponds to a confidence level of 95 percent. In other words, a deviation as large as 3 x 0.3 or 1 centimeter should happen less than 5 percent of the time in my data if it is a statistical fluke.

The space weather conditions were identified as

```
25...Quiet
26...Quiet
27...Disturbed
28...Quiet
29...Quiet

1-25:
14:00   7.0
14:40   7.5
15:20   8.0
17:20   8.5

1-26:
10:40   7.0
15:30   4.0
16:10   4.5
17:00   6.0

1-27:
10:00   11.5
10:20   12.0
10:45   12.5
11:25   13.5
12:40   16.0
13:25   15.5
13:40   15.0
14:25   15.0
15:20   14.5
15:50   15.0
16:20   15.5
16:40   15.5
17:15   16.5

1-28
13:25   17.0
13:45   17.0
15:00   17.0
15:25   16.0
16:30   16.0
17:20   16.0

1-29
9:00     7.0       shifted 'zero' from 17.0 back to 7.0
9:45     6.0
10:35    5.0
10:55    6.0
12:15    6.0
14:40    5.5
15:00    6.0
15:35    5.5
16:35    5.5
17:20    6.5

```
Note: Sunrise is around 7:00 and sunset is around 17:00 Eastern Standard Time. Exact times can be found elsewhere. Also, on the morning of 1-29, I discovered that the magnetometer was still reading +17.0, so I decided that, based on the unusual previous days record, that some kind of odd 'settlement' had happened with the instrument, and so I physically moved the magnetometer to reset the null position at 7.0. Future data will confirm whether this was the correct diagnosis, or whether there is currently some very large amplitude magnetic shift going on locally!