Monday, March 5, 2012

SMMART Science:
St.Patrick's Day
Green Cabbage Juice

Cabbage isn't just nice with a helping of Corned Beef!  Use purple cabbage juice as a pH indicator to tell you if a substance is acidic or basic.  Purple cabbage, tumeric, and beetroot are just a few natural plants that contain anthocyanins.   Anthocyanins are members of the flavonoid group. In an acidic solution there are lots of hydrogen ions and the addition of hydrogen ions to the anthocyanins alters the wavelength of light that is reflected by the molecules. (
You can easily test the pH (amount of Hydrogen ions) in substances around your house.
-Cut a head of purple cabbage in half. 
-Chop up the cabbage half into about 2 cups of chopped cabbage and put it into a large bowl (lid optional). 
-Pour boiling water over the cabbage until the cabbage is covered.  If you like, you can cover the bowl to keep the water nice and hot. 
-Let the cabbage seep for 10 minutes.  The water will turn a nice purple color. 
-Remove the cabbage and keep the purple liquid.
-Pour a little purple cabbage juice into several little bowls.
-Slowly add a substance to the cabbage juice in a little bowl and observe the color change!
Purple color= Neutral= pH7
Red color= Acidic
Green/blue color= Basic

The pH scale goes from 2(highly acidic) to 14(highly basic), with 7 in the middle being neutral

Try testing lemon juice, vinegar, soda, milk, laundry detergent, and household bleach.
Freshly squeezed lemon juice2.5
Freshly squeezed orange juice3.0
Tomato Juice
Bottled Lemon Juice
4.0 to 4.5
Black Coffee5.0
Water7.0 (neutral)
Baking soda9.0
Milk of Magnesia10.7
Domestic Bleach 11.0
Chocolate, honey, molasses, sour cream, buttermilk, brown sugar, natural cocoa powder, etc.mild

Add a little baking soda to the red (acidic) cabbage juice and watch the baking soda neutralize the acid to a purple.
Is Soda Good for your bones?

Test your favorite it acidic?  Soda can cause your body to pull Calcium from your bones to neutralize the acid.  This may contribute to osteoporosis.  Some experts suggest that if a person has a healthy diet, this really isn't a problem.  Others say that some people fill up on soda throughout the day and don't have a healthy diet.  These are the people who may be more at risk of osteoporosis from drinking carbonated beverages.


Johanna said...

I saw you this morning on GTU. This is such a great idea, I am going to try it with my cub scouts. They will love it.

SMMART ideas said...

Hey Johanna,

Thanks for the comment! I LOVE this fun, easy and really engaging science activity! Good luck with the cub scouts and let me know how they liked it!


Marissa Maxfield said...

Hey cutie!! This is so fun and I am doing it with my kids today! Also, thank you for the books-they were great! :)

SMMART ideas said...

I bet Sydnie LOVED watching the colors my girls did. I'm still trying to think of what else we could try around the house to see if it's more acidic or basic...


Related Posts with Thumbnails