Sunday, May 20, 2012

PH Lab

Cooking the Cabbage Juice.
Setting up the experiment.

Baking Soda and Cabbage Juice.

Pretty cool, layer of soap on the bottom, Cabbage juice in the middle, and soap on top.
Dish washing Soap.

Lysol Kitchen Cleaner.

Toilet Bowl Cleaner

Ammonia and Cabbage Juice.

Laundry Detergent.

Vinegar turned pink.

Soy Milk- It's actually a pale green color.

Apple Juice and Cabbage Juice.

Here we have (left to right) Baking Soda, Soda Pop, Toilet Bowl Cleaner, Dishwasher Detergent, and Laundry detergent.

Then it’s Apple Juice, Vinegar, Lysol Kitchen Cleaner, Milk, and Ammonia.

Red color (Very Acidic): Apple juice (peach), Dishwashing Soap (red, purple), Vinegar (hot pink), and Soda pop (orange)
 Purplish color (neutral): Laundry Detergent (bright blue)
 Green/ Yellow (basic): Ammonia (neon yellow), milk (ivory), kitchen cleaner (green), baking soda (teal but more green than blue), and toilet bowl cleaner (light green). 
For me, the coolest part of this experiment was seeing what color the product would turn when it get's mixed with cabbage juice. 

In case you are interested in doing this experiment:
At home:
Cut up a couple of leaves of red cabbage, place in a small pot on the stove and cover with about 1.5 to 2 cups of water. Boil the cabbage for about 5-10 minutes until the solution has a dark purple color. Allow the contents to cool and then decant the liquid into another container; a glass jar would be ideal. This is your acid/base indicator
Testing the products
1. Collect 10 containers that can be used to test the household items. The containers should preferably be clear glass but could also be a small white bowls or anything that allows you to clearly observe the color. In the lab, vials will be provided.
2.    Test each product see how it changes the color of the red cabbage solution. To test a liquid, pour a few mL (about 1-2 tablespoons) in a container and along with the same amount of cabbage extract. To test a solid, dissolve a small amount of the solid in a few mL of water and then add cabbage extract.
3.    Compare the color of your mixture to the picture provided and record the pH. 4.    Repeat this procedure for all of the household items on the list. 5.    If you are doing the experiment at home, take digital pictures of yourself with
at least three of the colored solutions in which the colors are clearly visible. The pictures should include at least one very basic solution (green end of the spectrum) and one very acidic solution (red end of the spectrum). Be sure to indicate what the solutions are.
6.    Place a small amount of cabbage juice indicator in a clear glass container. (In the lab, a beaker will be provided.) Use a straw to blow bubbles through it. You may or may not see the solution change color. (Results will vary and may depend upon how concentrated your cabbage juice is as well as how acidic or basic it is to start, variables which are difficult to control.) If you do see a color change, note, in particular, whether your breath caused the solution to become more basic or more acidic.
The colors you see come primarily from a class of compounds called anthocyanins. The anthocyanins are responsible for the reds and purplish colors of autumn. They are also found in summer leaves of plants such as red cabbage, red lettuce, red plum; flowers such as, roses, geraniums, dark pansies; fruit such as, cherries, red apples, grapes, tomato, plum; roots such as, beets and radishes; bulbs such as, red onion and petioles, such as, rhubarb. These anthocyanins are water-soluble and dissolved in the cell sap. If the cell sap of a leaf is acidic then the anthocyanins show a red color. If the cell sap is less acidic then the anthocyanins appear purple.
Cabbage juice contains anthocyanins. As the cabbage juice is exposed to different pH solutions, the anthocyanins show different colors. Very acidic solutions will turn the anthocyanins to a red color. Neutral solutions will result in a purplish color. Basic solutions will appear in the green-yellow region of color. Therefore, it is possible to determine a solution 1⁄2s pH on the basis of the color it causes the anthocyanin pigments in red cabbage juice to turn.

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