Amy Lawson & Becky Heenan
Pre-Kindergarten (and upwards)

Activity: “Colour Changing Potion.” This is an easy experiment that could work with any elementary grade, even as early as pre-kindergarten. A red cabbage is soaked in hot water, and it releases a pigment (called flavin) into the water. Adding different elements to the water – some acids, some bases – will cause fun and surprising colour changes to the water. To the students, it is their own magic potion! To the science teacher, it is a great hands-on activity that works well in a learning center format, as we will be doing here.

We hope that the activity can accommodate different kinds of learners. Those who are kinaesthetic will appreciate being able to be hands-on and create the reactions themselves. Others may favour the ability to draw the results themselves, and still others could orally or textually recall the results and make predictions as to what others things could do.

Source: The Science Cafe website includes this lesson, as well as other great ideas for Halloween and other events. This particular lesson may be found at http://www.sciencecafe.org/content/article/color-changing-potions.

Curriculum link: Science. Pre-kindergarten has a fairly open design, but it lays the foundation for areas of study such as matter (changing properties) and colour.

Links to other subjects: Art (colours mixing), English Language Arts (write or explain to teacher what they observed) and Math (counting drops put into cups and measuring how much of each ingredient is needed).

Materials: Red Cabbage
Bowl
Marker
Five Clear Cups
Boiling Water
Knife
An Adult
Baking Soda
Lemon Juice
Vinegar
Antacid tablets

Activity overview:

1. Finely chop the cabbage until you have two cups.
2. Place the cabbage into a bowl and add enough boiling water to cover the cabbage.
3. Let the cabbage soak for 15 minutes until the water changes colour (it will appear red, purple or blue.)
4. Distribute the cabbage juice evenly among the five clear cups.
5. Number the cups 1-5.
6. Add baking soda to cup 1 until the colour changes.
7. Repeat with lemon juice in cup 2, vinegar in cup 3 and antacids in cup 4.
8. Leave cup 5 with just the cabbage juice.
9. Compare the colours in all five cups. What do you notice?

What will students learn best as they do the activity? Ideally, how reactions may be caused! They will see how making small additions to things may cause great changes. Why do these changes happen? Why do some things create no change at all? The important thing is to encourage them to ask questions, even if they may not always find the answers!

How will you evaluate the students? We will evaluate the students by observing them during the experiment. Do they appear to be interested? Curious? The goal is to provoke their thinking and to encourage them to explore the properties, so observation will be key. This is why the “center” format, which caters to small groups of students at a time, will be valuable. In small groups, they will all have a chance to participate. We will read any written responses they may share, and/or listen to their oral responses as well.