This week I had the pleasure of whipping together an unplanned inquiry-based learning exercise with my students–and being wonderfully surprised with the participation and learning that occurred! The students had ‘pullouts’, which I don’t understand at all, but it meant that I could interact with a small subset of students without worrying about sticking to the curriculum. I had very little time to think about what to do, so I focused on teaching with balloons, since there are a bunch of discrepant events and activities that can be done with them (e.g. google “balloon party tricks”). To warm them up, I asked them what they knew about balloons. Common responses were: they can be blown up, they are stretchy, they are made from rubber, they are different colors, etc. Next, we investigated what happens if a blown-up balloon is held above a flame, either filled with air (it pops!), or filled with water (it burns but will not pop!). It was also great fun to try to put a needle through a balloon…
But, the REAL fun began when Ms. Reno brought out the balloon cars! The cars had an attachment point for a balloon which could be blown up from the back of the car with a straw. We began investigating the relationship between the size of the blown up balloon and the distance the car would travel. One groups’ hypothesis was that the larger the balloon, the farther the car would go. Another’s was that if the balloon was too large, the car wouldn’t go at all. We tested the opposing hypotheses by blowing up the balloons to different sizes (measured as circumference) and measuring the distances the cars travelled with a meter stick.
Since I have never played with these cars before, I had no expectations of what would occur. Intuitively, I thought that larger air displacement from larger balloons would push the car further. Guess what? Both sets of student hypotheses were correct!
We graphed the results of our trials and discovered that 1) As balloon circumference increased, so did the distance the car traveled–to a point, 2) once the balloon reached a critical large size, it unbalanced the car into a wheelstand, which prevented it from moving at all! Best of all, the students were able to extrapolate from their data and realize that the relationship took the form of a parabola. Way to go, Central Middle 7th graders!