Mystery Science: Part IV: Testing the Contents of the Glass

We used homemade turmeric strips and some litmus paper since we had already experimented with red cabbage indicator.

The first step to using an pH indicator is to have some control strips for comparison. We used cola for our acid control, and we used a 1/2 teaspoon of baking soda mixed with water for our base control. We dipped our turmeric strips in and saw that they turned orange-red in the base and stayed yellow in the acid. There may be a slight color change due to the coloring in the soda, but it is not much of a change.

Now we testing the mystery glass contents...

and found that the contents of the glass was more of a base than an acid...and so we concluded that there was sleeping potion in the glass.

We also used litmus test strips, first in our controls...

and then in our mystery liquid, with the same results.

If the cola contained a sleeping potion, who does this indicate might be involved in the kidnapping?

Who do you think would have access to and knowledge of the sleeping potion?

Check the names off on your worksheet.

You can also make a guess in the poll. You can always change your guess.

Sources:

GEMS: Of Cabbages and Chemistry

Grades 4-8

4 Sessions

88 pages

Students explore acids and bases using the special indicator properties of red cabbage juice. The color-change game Presto Change-O helps students discover the acid-neutral-base continuum. They learn that chemicals can be grouped by behaviors, and relate acids and bases to their own daily experience. An “Acid and Aliens from Outer Space” extension activity can be presented to reinforce student learning or as an assessment. The unit is an excellent lead-in to the GEMS guide Acid Rain.