You will find here all the frequently asked questions concerning "Solar Balloon - micro:bit version"
How much time should we anticipate for balloon construction?
With students divided up into different building stations (construction of the balloon’s envelope, the balloon’s basket, and connecting and test the on-board electronics,) the construction of the balloon itself takes about 4 hours The most ideal is to take time to explain all the points of the program using the kit, so it’s best to count on a little more time. The project is very adaptable, for example, for the electronic component, you can give it to the students already assembled, let them make the connections, or let them modify the board’s code with fill-in-the-blank code.
What does the kit contain?
The kit contains all the necessary components to build a solar balloon measuring 4 meters in diameter as well as the electronic mini-weather station that will be placed in the balloon’s basket.
How much time should one anticipate to fly the balloon and take measurements?
The flight is highly dependant on the weather (see next question). If there are good conditions, the balloon will take off quickly and an hour will be adequate to inflate the balloon, fly it, and recover its data. Another session should be anticipated to extract the data and graph it in Excel.
What weather conditions are needed to fly the balloon? What seasons?
The flight requires a sunny day without wind. When it is lit directly by the sun, the balloon will take off quickly (within about 5 minutes). A slightly cloudy sky can also work if you wait for a “sun hole”. On the other hand, wind is a real problem because the balloon can be torn from gusts of wind greater than 10km\h. Wind is generally weakest in the morning because so-called “thermal winds” are not high, thereby making ideal flight time between 9am and 12pm. The variable that matters is the difference in temperature between the inside and the outside of the balloon. The ambient temperature does not make a big different, so the season does not matter. You will find a flight condition predictor here.
How high can the balloon go, is specific authorization needed?
The balloon must be held in place by two 50m ropes (included in the kit), which allow the balloon to fly up to 50m. Regulation authorises captive flights up to 50m without specific authorisation. To answer the question: \"What happens if we let go of the ropes?\", we tried a free flight (without ropes) from Paris. The balloon reached an altitude of 8500m and took what we suppose must have been a breathtaking video, but unfortunately we couldn’t retrieve the balloon and camera because the GPS tracker didn’t function correctly. We’re going to try the experiment again soon so you can show the video, along with the pressure, temperature, and pollution levels in relation to altitude to your students.
What is the lifespan of the balloon? Number of potential uses? Fragility?
Once the balloon is constructed, it be flown an indefinite number of times. It cannot, though, be deconstructed, then constructed again. It is fragile, but quite easy to repair with tape. Once deflated, it can go in a student’s backpack, so transporting it is not a problem. The best to use one kit per class so students can see all the steps of construction and learn from the experience.
Can one quickly learn the electronic software? About how long does it take?
The electronic component is based on Arduino technology, that was created with simplicity in mind. The instruction manual we wrote contains step-be-step instructions. Someone completely unfamiliar with this type of electronics would take about 2 hours (including connections).
What are the measured parameters? Do they vary during the course of the flight?
The electronic component measures pollution, temperature, pressure, and altitude. We can clearly see changes in the pressure and altitude, while the lowering of temperature is less significant. Pollution (CO2 level) varies according to where the flight is launched from, which also can be interesting to see. In any case, it is interesting to see class variations (when one blows on the sensors, one can clearly see variations in temperature and CO2 levels.
What can we do with the acquired data?
The data can be used to show the physical properties of the atmosphere (pressure and temperature variation in relation to altitude), the detection of pollutants (CO2 by blowing on it, butane with a lighter…). It can also initiate students to computer coding as well as other educational opportunities that we haven’t thought of yet.
What is the electronic component’s level of autonomy?
The sensors make regular recordings during a desired period of time, the only limit is its battery, which has a lifespan of about 10 hours.
A complete kit to construct a solar balloon and two mini-weather stations in order to make comparative measurements.