This program introduced fourth-and fifth-grade students to high-altitude ballooning and provided them hands-on experience in constructing an experiment. In four sessions at each of three schools, the students investigated relevant scientific concepts, built and calibrated temperature-sensing circuits called CricketSats, and launched their CricketSats on helium-filled balloons. This project was part of UM Health Career Opportunity Program’s Science Opportunities for Kids (SOKS) project.

Session One: Introduction

           In the first session, students learned about the UM BOREALIS program and were given an overview of the experiments that have been flown on our platforms. They also were introduced to the CricketSat temperature sensors that they would be constructing in the next session. In preparation for that part of the project, Session One was spent performing a lab on lift and a lab on Ohm’s Law. In the lift activity, students attached small objects to helium-filled balloons and launched them indoors to see how the balloon’s ascent rate varied with the mass of the “payload.” In the Ohm’s Law lab, students learned the concepts of voltage, current, and resistance. They set up a circuit with one resistor and used digital multimeters to measure the current through and the voltage across the resistor. Graphing these values, they observed that V/I=R.

Session Two: Circuit Construction

           In the second session, students assembled their CricketSat kits. After learning appropriate techniques and safety precautions, they followed a circuit diagram to put together and solder their CricketSats.

Session Three: Calibration and the CricketSat Signal

           In the third session, students learned more about how their CricketSat works. They learned that the thermistor in the circuit is a temperature-sensitive resistor and that the signal emitted by the CricketSat therefore changes with temperature. In order to understand in what way the signal changes, the students learned about waves with a National Instruments LabVIEW VI created by UM BOREALIS. This VI generates and displays a waveform, allowing the user to change properties such as amplitude, frequency, and DC offset. Students used this program to learn about these wave properties and their meaning in context of the CricketSat signal.
          Also in this session, students calibrated their CricketSat circuits. They covered the thermistor in ice and read its temperature off a thermometer at the same time their partner read the signal’s frequency from the ground station. Their temperature-frequency data pairs were later graphed in Microsoft Excel to produce a calibration curve. The calibration process also gave students a chance to become familiar with the ground station equipment before the launch.

Session Four: Launch

           In the fourth session, students attached their CricketSats to parachutes and helium-filled balloons and launched them from their elementary schools. They used the ground station to observe the temperature falling as the balloon rose.

The CricketSat and Ground Station:

           The CricketSats are wireless temperature-sensing circuits containing a 555 timer and a thermistor. They produce an audio tone whose frequency changes with temperature. This signal is received by a Kenwood TH-D7 Ham Radio, which sends the signal to a PC via a National Instruments USB-6009 Multifunction Data Acquisition device.
          The signal is then processed in a LabVIEW VI created by UM BOREALIS. The VI processes the data in real-time and performs a FFT, displaying and recording the strongest frequency from the signal and converting it to temperature. The frequency-temperature conversion is performed with user-input coefficients from the calibration curve produced by the students in Session Three. Both frequency and temperature data are recorded and saved to a file.
          The National Instruments USB-6009 Multifunction Data Acquisition devices and accessories (connectors, labels, and screwdrivers) as well as LabVIEW Professional Development Systems software packages were provided by NI through a National Instruments Student Partnership grant. Each of the three participating elementary schools and the University of Montana received one USB-6009 device (with accessories) and one software package. Learn more about National Instruments educational resources and the National Instruments Equipment Grant Program.