Saturday, February 25, 2017

UAVSonde for NearSys Station, 25 February 2017

The pressure sensor was recalibrated this week at the Boise Airport. The National Weather Service reports the air pressure hourly and converts it to sea level pressure for aircraft. I did not make an adjustment for the local temperature, so I will need to recalibration again some time. Afterwards, I will investigate how temperature affects the readings from the pressure sensor I'm using.

UAVSonde data were collected at 11:00 AM. Here are the data.

Altitude: 2,303 feet
Temperature: 40 *F
Relative Humidity: too cold to measure
Pressure: 929.5 mb

Altitude: 2,621 feet
Temperature: 36 *F
Relative Humidity: too cold to measure
Pressure: 916.9 mb

Friday, February 24, 2017

Balloon Launch for the Earth Science Classes at the Treasure Valley Math and Science Center

Friday, February 24th was partly spent launching two weather balloons for my school's earth science class. Currently the students are in the meteorology unit and a balloon launch and UAVSonde flight were perfect activities. One launch took place in the late morning and the second one in the early afternoon. The payload for this launch was a bag of student-made paper airplanes. Students put their names on the planes they made. Contact information for the school was printed on the airplane in case it was found again. A second, smaller balloon acted as the altitude switch that would open the bag carrying the paper airplanes.

The first launch took place in clear skies. So the students watched the balloon climb for about three minutes, or when it reached an altitude of 3,600 feet AGL. The balloon was observed drifting in the southeast direction, indicating winds were from the northwest.
The morning Earth Science class getting ready to start the countdown.
The second launch took place after puffy cumulus clouds had appeared. Students observed that the weather balloon disappeared in a cloud 2 minutes 45 seconds after launch. This length of time indicated the cloud base was at an altitude of 3,300 feet AGL. Students saw the balloon again about 10 minutes after launch, or at 12,000 feet AGL. This time the balloon had moved further north and heading generally in that direction. The second observation showed students that the winds were blowing in a different direction at that altitude.

The second balloon on its way to a cumulus cloud

Following the balloon launches, I sent up a UAVSonde and collected weather data. Here are the data from those flights.

Morning UAVSonde
Altitude: 2,426 feet
Temperature: 36 *F
Relative Humidity: too cold to measure
Pressure: 916.9 mb

Morning UAVSonde
Altitude: 2,916 feet
Temperature: 29 *F
Relative Humidity: too cold to measure
Pressure: 913.1 mb

Afternoon UAVSonde
Altitude: 2,588 feet
Temperature: 43 *F
Relative Humidity: 18%
Pressure: 918 mb

Afternoon UAVSonde
Altitude: 2,818 feet
Relative Humidity: 24%
Pressure: 912.4 mb

This was a fun pair of launches and reinforced how great this would be to do for a living and not just a hobby.

Thursday, February 23, 2017

Fun with Electrostatics Class, day 2

On the second day, Students learned about the Electrophorus and Leyden Jar. The Electrophorus was popularized by Alessandro Volta and is a pertpetual source of electrostatic charge (or at least until its insulating base loses charge). The Leyden Jar was developed by several people, one of them working at the University of Leyden (Pieter Musschenbroek). The Leyden Jar is a storage device. One can add charge to it to increase the charge stored in it.

So after building both devices, Students taking the Fun with Electrostatics class used the Electrophorus to generate a charge and then added that charge into the Leyden Jar. A shock from an Electrophorus is mild, but the shock from the Leyden Jar is very strong after adding charge from the Electrophorus ten times!

That's another charge added to the Leyden Jar

Monday, February 20, 2017

The Growth and Evolution of a Cloud in Three Parts, visible, near infrared, and thermal infrared

I put together a 80 second time-lapse video of a cloud east of NearSys Station. The images were recorded using the BalloonSat Imager that I am developing. The BalloonSat was turned on its side and programmed to record images with its three cameras every few seconds.

The video is now online at my YouTube Channel at,

The resulting video shows the cloud first in visible light. That way viewers can get their bearing. The near infrared image penetrates the atmosphere so well that details in the cloud are much sharper. The final portion of the video shows the cloud during the same time frame, but in heat images.

One thing to note is how the small cumulus cloud that popped up before the cumulonimbus is cooler than the cold stratus cloud above the cumulonimbus.

Here are three screen shots to help illustrate this.

Color Image

Near Infrared Image

Thermal Infrared Image

Sunday, February 19, 2017

UAVSonde for NearSys Station, 19 February 2017

UAVSonde data were collected at 7:10 AM. Here are the data.

Altitude 2260 feet
Temperature 36 *F
Relative Humidity 100%
Pressure 1002.9 mb

Altitude 2637 feet
Temperature 40 *F
Relative Humidity 100%
Pressure 985.0 mb

Thursday, February 16, 2017

Fun with Electrostatics Class: Day 1

The first day of Fun with Electrostatics taught students the history of electrostatics (briefly), the background on the nature of electrostatic charge, and the triboelectric series. The students then did basic experiments to reinforce what they were taught. These experiments included charging objects by friction, polarization, and conduction and seeing that like charges repel each other.

Kurt levitating a plastic ring using only electrostatic charge.
It's science magic! 

Monday, February 13, 2017

Great Horned Owl

On many of my recent evening walks, I have caught the hooting call of two Great Horned Owls. I have even managed to catch sight of one of them. This evening's walk was a little different in the owl decided to stay in place as I used my cellphone camera to get a picture of him or her.

Ever get the feeling you're being watched?