Have you ever written something that keeps giving you enjoyment or teaching you long after you’re done? Something that you LOVE but that you just know will not provide the same level of enjoyment or knowledge to anyone else? I had one such moment yesterday as I set up my classroom for our Friday Experiment. I waited all week with excitement, tried the experiment three times at home (just to be SURE that it really works!), and was almost completely prepared by the time I got to school Friday morning…if you forgive the few minutes of panic as I raced through the hallway asking fellow teachers for balloons.
Though I knew what the experiments outcome would be, I waited with baited breath to find out what my student teams a) came up with for their hypothesis and b) how they would react to the outcome.
I set up our center ‘activity’ table (a new addition for the new year) with a box of Baking Soda, a bottle half filled (about 8 oz) of Vinegar, a balloon, a set of measuring spoons, and a funnel along the left side. On the right hand side of the table I laid out a bottle of Sprite with a little off the top, a funnel, a balloon, and a packet of Pop Rocks (strawberry, but I don’t think the flavor matters). I had students break into two teams. Each student was to draw out the ‘ingredients’ however they saw fit, then discuss with their team to come up with a timeline and hypothesis for the experiment. One team was to focus on the left side, the other on the right.
We had an astonishing (at least to me) amount of spot on, or almost so, guesses at to what I would do and what would happen. Then we had a few incredibly interesting but not very close to truth hypothesis…that make me want to try out what they suggest!
After about ten minutes of group talk and hypothesis writing, everyone turned to the center of the room and watched me perform the experiment.
1) use funnel to place a tablespoon of baking soda in a balloon, use other funnel to place pop rocks in second balloon.
2) open bottle and place mouth of balloon CAREFULLY over mouth of respective bottles.
3) raise balloon and release dry ingredient into the liquid below.
If all goes correctly, Sprite and Pop Rocks or Vinegar and Baking Soda will react together to release the gas and blow up their balloon. In the second class, a student requested a bottle of EVERYTHING (i.e. vinegar, sprite, pop rocks, and baking soda). Surprisingly, this set up yielded a pretty awesome result as well.
Sprite and Pop Rocks blew up a balloon with more length than width, and only a small amount of length (around 5 centimeters for 3/4 of the classes. Last class had a larger balloon at almost a full inch and a half in length).
Vinegar and Baking Soda has a more violent reaction that the Pop Rocks and Sprite, so that the balloon stretches in width, as well as height, and is several inches in size. According to my students, it tries to ‘boom’ but just ‘blows up’. (I love their love of creative sentence structure!)
Finally, the all in bottle creates a reaction somewhere between the other two, filling up its balloon with a beginning reaction that is violent and slows down to a delightful lava lamp effect as you watch the pop rocks jump around within the liquid. The balloon fills up to approximately 3 – 5 inches in length and 1.5 inch in width…though my last class of the day lucked out because I finally hit it just right..that balloon actually filled out to be slightly larger than the vinegar and baking soda one!
Some students wanted to measure the different sizes of the balloons. One suggested we try the experiment with every color of balloon available to us…or re-do the experiment using all the same colors of balloon…just in case. And a few wanted to drink the sprite mixture (I didn’t let them 😦 ) But amazingly enough, almost all of my 80 students could actually EXPLAIN the reaction and WHY it happens! Not only that, but they made the connection between solid (bottle), liquid (yup), and Gas all having volume and mass…and explained to me how the air displaces as we moved (CAREFULLY) the bottle and poured liquid into, and then out of, the balloon (still attached to the bottle’s mouth).
To call me a proud teacher is a bit of an understatement at this point. To top it off, my principal came in and observed the final installment of our day and got to see a class who is usually a bit slow and behind the others (due to behavior issues and a need to change my teaching style for them, ick!) excel and ask do to do more work to figure out exactly what was going on! (and I only had to get on to two students while she was there, a new record!)
Ok, you know you want to try this out so my one suggestion is that you choose something a bit more carbonated than Sprite. Coke worked well during my home tests. If you try it out with something else, let me know! I loved this so much, I think we’ll do it again next year!