Science Class #4-Acids and Bases

The kids really enjoyed this one, it was right up there with forensics!We talked about the PH scale, what acidic and basic means and what common acids/bases are as well as what neutral is and what substances are neutral.

Common acids: Fruit juice, battery acid, vinegar, lemon juice, shampoos

Common bases: bleach, soap, hair conditioner, drain cleaner, baking soda

I also talked about how both strong acids and strong bases can be dangerous and why and how they interact with each other and with weaker acids/bases.

For activities we:

Made indicator solution from red cabbage* and tested the PH of several items-baking soda, citric acid, vinegar, lemon juice, lime juice, crushed antacid tablets, crushed vitamin C tablet, witch hazel and water. Once the kids had tested everything they decided to see what would happen when they mixed some acid indicator with some basic indicator. It went back to neutral in most cases, but if it was a strong acid it would sometimes still register acidic.

Had some fizzy fun by adding several of our proven acids (lemon juice, lime juice, vinegar) to some baking soda and seeing if a stronger acid reacted more strongly. The kids then checked some of our bases to see if anything happened (nope) and the neutrals as well (ditto).

Made bath bombs to take home and have more fizzy fun!

There weren’t many links this week but here they are:

http://sv.berkeley.edu/showcase/flash/juicebar.html

http://www.quia.com/jg/347025.html

http://www.york.ac.uk/res/sots/activities/acidtest.htm

Chemistry for Every Kid by Jan VanCleeve

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* I used the simple directions on the University of York website above (basically just adding boiling water to chopped red cabbage). I have since seen much more complicated directions for making an indicator solution. I can’t say if they work better then the one I made, but mine did work (turned red/pink for acids and blue/green for bases) and it was SUPER easy.

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