Meeting The Mentor, part 4: The Alchemist's Guild


Using lessons in chemistry, young alchemists apply what they learn about pH and chemical reactions as well as other chemistry concepts to formulate their own potion "recipes" which they can then use to help their comrades defeat the enemy. These recipes have to named and written in Latin, too! There is so many things that can be done with this concept, that you could easily run a week-long Alchemist Guild portion of the camp.
There is no doubt that when we think of magical potions, we think of bubbling mixtures and liquids when poured together changing colors! This is what we will also do in our Alchemist Guild.

In Advance


You will need to make up some red cabbage pH indicator in advance of the camp day. It can be stored in the refrigerator until it is needed.
  1. Take about 1/3-1/2 of a small red cabbage and slice it into large shreds.
  2. Put the cabbage shreds into a blender.
  3. Add about 2 cups of boiling water.
  4. Turn on your blender and blend until you have a mush (yes, mush is a scientific term on this blog.)
  5. Put a strainer over a bowl. Pour the mush into the strainer, straining out the juice.
  6. Now you can  use this red cabbage juice as an indicator. Acids will turn the pigments in the indicator to a reddish color; bases will turn the pigments bluish or yellow-green.

You should get about a two-liter bottle of acid/base indicator liquid from a half a head of purple cabbage. You will also need a a bottle of vinegar, a bottle of lemon juice, a bottle of ammonia, a carton of milk and containers of water with baking soda mixed in and water with crushed Tums mixed in.


Introductory Activity


Tell your students that they can do whatever experimenting they want with it except they cannot eat any of these materials. I know they are all non-toxic, but they are not particular good just to drink and it sets a good precedent for the chemicals they will use later on in chemistry. Let them mix and pour and experiment, feeling like wizards.



pH Chemistry Lesson

If your students have not done experiments with pH, you will need to discuss with the students about whether each of these liquids tasted sour or not. Discuss the correlation between their taste and whether the liquid was an acid or a base. Gently guide them to see that all the ingredients that were sour also turned pink, indicating that they were acids, whereas the liquids that were slippery when you rubbed them between your fingers and turned green were bases.  You can explain how acids contain hydrogen atoms (H), and bases have a oxygen and hydrogen atom combination (OH).
If your students are ready, you can add information about pH and covalent compounds. You can also discuss precipitates and how acids and bases turn into salts and water when combined. 

You can help them conclude that the vinegar is now a known acid that ammonia is now a known base and that milk is now a known neutral liquid, so that they can have color coding to refer to as they tested other unknown liquids. 

Ask your students if when they were pouring the contents of one cup into another and whether they discovered that all of the cups will turn a purple. Guide them to the conclusion that this indicates that the liquids had neutralized and were not either base nor acid.

Advanced Chemistry Lesson



In another lesson, you can help your students in determining the endpoint of a neutralization reaction. Put a 1/2 cup of vinegar in a jar and then add 3 Tablespoons of red cabbage indicator. Have your students note the color, and all the color changes, from pink to pinkish-purple, to a purple and then to a bluish-purple and then eventually a blue-green.
Next, have your students add ammonia a tablespoon at a time, and note the color. It is hard to see the color perhaps in  this photo, but it turns a blue-green. If you note the color each time, you can chart these on a graph and see that it stays pink for a long time and then suddenly there is a color change. This is the point in which they neutralize and then you see another leap as it goes to the blue-green of base.  

If you wish, you can also perform a titration using a polyprotic acid. A polyprotic acid  has more than one point of neutralization. You can clear soda (such as Sierra Mist). Have your students add the red cabbage indicator and record the color on a graph.

Now have them slowly add tablespoons of baking soda water and recorded the colors as it changes.

 If your students look at the graph of the titration, you can see two "bumps" where there are leaps in the color change.

If you have younger students, you can have them pick out Unifix or Lego blocks of the right color and you can make the graph using the same colors on the graph.





Other Chemistry Lessons

The Hydrogen Peroxide-Yeast Experiment

BEWARE: This next one is messy. You will need to have on hand hydrogen peroxide and liquid dish soap, a packet of yeast, as well as an empty bottle such as a water bottle, some liquid food coloring and a funnel.

Pour into an empty water bottle 4 oz of hydrogen peroxide and 2oz of liquid dish soap...

and a few drops of food coloring.

In a separate container, mix one packet of active yeast with some warm water, and let sit for 5 minutes.
When you are ready, pour the yeast mixture into the soda bottle through a funnel and watch the reaction!
It is more fun than the baking soda and vinegar reaction.
The hydrogen peroxide has in it, among other things, oxygen molecules (hence the oxide part). When you add yeast to the hydrogen peroxide, it acts as a catalyst. A catalyst speeds up the reaction rate by lowering the energy level needed for the reaction. In this case, the yeast, acting as a catalyst, sped up the otherwise slow decomposition of the hydrogen peroxide, so that the peroxide molecule released its oxygen atoms faster that it otherwise would.
The dish soap is added so that the bubbles of released oxygen hold together into a foam.
For your older students, the formula is-
2H2 O2 (aq) turn into 2H2 O (l) + O2(g).
(Sorry, I can't figure out my subscripting, etc.)


Additional Activities



If you have the time and interest, you could also do the Mentos and diet cola demonstration or make some other concoctions and make peanut brittle and/or root beer floats for the snack, (scroll to the end of the post) all the while inserting some chemistry information. 

Making Spells

There is more to alchemy than the stereotypical turning items into gold, and your students can get creative with writing their own "spells" which can have a connection to chemistry. Some they may have trouble stating the chemistry behind it, since alchemy wasn't a real science and things like transmuting and polymorphing can't have an actual scientific explanation. In that case, have them explain why it couldn't actually happen and that will suffice as a test of their knowledge. If they have trouble coming up with suitable potions, you might want to suggest purifying food and drink and transmuting metal to wood might be a good place for them to start with creating useful "spells." Make sure they give a brief description in Latin in order for the "spells" to be approved for use. 

Making the "spells" on "scrolls" made from paper aged with tea bags is also a good activity.

Table Game: Quest for Arete

Q4A: Starter Set
Play Quest for Arete. As their website says, "experience the 'magic' of the Elements in this exciting Educational Game of spells and potions."
Each card represents a “Magical Element” taken from the Periodic Table of the Elements.
Players Learn Chemical Symbols and how to Read Chemical Formulae
Why is Iron’s symbol “Fe”? Why is Lead’s “Pb”? You’ll see why!
Scores are based on Electron Configuration of the Elements (Valence Electron Count)
Each Spell’s Score Uses a little Brain Power: Roman Numeral Conversion and Math

sources:
  • Exploring Creation with Chemistry, Jay Wile
  • Real Science 4 Kids, Chemistry Pre-Level 1, Level I, Level II
  • 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.

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