color changes

While we’re hosting Science it the Parks each summer, we also spend some time looking at future activities.  Just yesterday afternoon, the staff were making sure that the bottles of soda (orange, grape, strawberry, and pineapple Fanta) were drunk as quickly as possible so that we could use the empty bottles for new sound experiments.  This is just evidence of how dedicated and professional we are as science educators.

Some of our work, play, and other activities never make it to the parks for one reason or another.  Once, we discovered that a solar hot air balloon disappears over the Wasatch mountains if someone lets go of the string.  There are some great things we can do with electric charge and thin pieces of mylar balloon, but it only works well inside.  And, just yesterday afternoon we were playing with using red cabbage juice as an indicator of how acidic or basic different liquids are:

There are good descriptions of using red cabbage as an indicator, or simply as a way to see how color can change dramatically with different chemical characteristics.  Steve Spangler describes our favorite method of getting this juice and testing it.  It’s as simple as putting it through a blender and adding hot water.  You could also order the red cabbage in a powdered form (here or here, for example), which is more expensive, but easier to have on hand when you need to do some quick science in the kitchen.

Why don’t we do this in the parks?  Mostly because this juice is best at a kitchen table, sitting down and unhurried, with an apron or other old clothes in case of spills.  Red cabbage juice makes impressive stains on clothes.  But, it’s easy to make and you have lots of things that are fun to test color changes with.  Vinegar and baking soda were what we were trying in our quick experiment, but you could also try lemon juice, detergents, and even different sources of water.

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