Wednesday, January 19, 2011

The worst smelling, best fun ever

I have a student that often tells me that the activities that we do are the "best ever." The day I let them go swimming in shaving cream was the "best ever," the day we spray painted snow for the first time was the "best ever," and the project I am about to tell you about was "REALLY the best ever."  At least that's what I am told.  
Inspired by an article by Bev Bos I set about preparing for a huge smelly purple cabbage juice experience.  
The inside of a cabbage is amazingly beautiful!

The first thing I did (as instructed by Bev Bos) was to chop 4 purple cabbages into medium pieces and boil it in two huge kitchen pots with water a few inches away from the brim.  

After the cabbage was floppy and the juice a very dark purple, I strained both pots into large bowls.  I combined the floppy cabbage into one of the soup pots and boiled it again.  I probably could have done this one more time before discarding the cabbage, but at this point I was up to my elbows in cabbage juice.  

I then used a funnel to transfer it to every available pitcher and jug we had in the kitchen. 

I haven't bothered to do the actual conversion to see how many gallons of cabbage juice there were exactly- but there were at least 10 (there are more jugs on the second level of the cart shown above).  The cabbage juice sat in my class overnight like this for use the next day.  To my knowledge this did not make it smell any better or worse than it did right out of the pot.  

I had over 40 plastic dixie cups set out with a tablespoon of lemon juice in each and over 40 paper dixie cups set out with a tablespoon of baking soda in each.  I also had 14 cups, (for 7 children that day), half full of cabbage juice set out.  THIS WAS NOT ENOUGH, and would have been even more insufficient if the 10 children that is normal for my class had been there.  They went through the cups of baking soda and lemon juice in about ten minutes and the cabbage juice cups in about half an hour.  It was an uphill battle from the ten minute mark on to keep the children supplied with all the baking soda and lemon juice they needed.  In addition to needing cabbage juice refills at the half hour mark, we ran out of the GALLON of lemon juice that we had and so, had to improvise with vinegar.  This was a good substitute, but vinegar, as you might imagine, is slightly more reactive with the baking soda than the lemon juice was.  It became a huge "who can make their cup overflow- competition,"  which was fine.  In the end we went through about a pound and a half of baking soda, a gallon of lemon juice, a gallon of vinegar, and hundreds of tiny cups. However, it was all worth it.  

Here are some pictures I managed to take before the shortages: 

You can see both the colors and some of the reactions from these pictures although they worked up some much more intense reactions.  As you probably could have surmised, when coming in contact with an acid the cabbage juice becomes bright pink red, with a base it become blue and then green because cabbage is an natural indicator.  The colors are really stunning.  

I had one little girl who came late, after everyone was done, and luckily I had set aside enough vinegar, baking soda, and cabbage juice for her to do the experiment.  She did this differently than any of the other children;  All of them, for the most part, spent their time dumping baking soda and vinegar/lemon juice into the cabbage juice, but she started by putting cabbage juice into the little cups that held either baking soda or vinegar.  

Hopefully you can tell, despite the poor quality of this picture, that she ended up with cups of bright pink and cups of dark green.  She then dumped them all back into the big cup and asked me to refill her little cups with vinegar and baking soda, which I did, and then dumped the now purple liquid in her cup back into each small one.  This time the vinegar cups were a magenta and the baking soda cups a dark indigo.  She repeated this procedure a few times before going the route all the other children did in the end- overflowing her cups.  

Needless to say the children were completely in love with this experiment.  They learned and observed so much.  I fully anticipate to be asked when we are doing this again for at least a month.  We will do it sometime again, but my nose needs a break from the smell of cabbage and this time I will know to have out at least a couple hundred cups of baking soda and lemon juice before starting.  

At the end of the day each child went home with a reused mini water bottle full of cabbage juice, and a note explaining to parents what this bad smelling drink was and what to do with it.  I know of at least two children who went home last night and relived the excitement of the cabbage juice with their parents and siblings in the kitchen, and hopefully more of them will tonight and tomorrow.  

If you are attempting this in the full scale project version some words of advice:

*Have a lot of materials in "unlimited quantities" prepared for them.  They fly through the supplies. 
*Double line several trash cans to have near the project site to make clean up easy
*Have a lot of towels prepared to clean up overflow
*Have as many adults as possible to help keep things running smoothly.  (We did this with two adults and really needed at least two more)
*Be prepared for your classroom to smell of cabbage juice the next day and be prepared with the appropriate equiptment


1 comment:

  1. My little one talked about this almost nonstop before dinner! You made quite an impression on her. Maybe this is the beginning of a love of science!