Kitchen Science: Discovering Acids and Bases Using Cabbage Juice.
Science is super fun with kids. Everything seems like magic. My little dude loves to do experiments so I am teaching him the whole scientific process little by little.
My little dude is in full time school. He goes to a good school and learns a tonne but he is such a little sponge he seems to need a lot more educational exposure. So at home we do a cross between homeschooling (workbooks to teach specific academic skills) and unschooling (experiential learning selected by him that teach him practical skills, for example, focusing on fractions as we learn to bake or using a compass when going for a hike).
He likes the unschooling better than the homeschooling but we do both. We spend very little money on either using mostly free web based resources and a few workbooks. ABCMouse has a cost but it's been worth it so far. I have not been thrilled with the home school science resources available. A lot of home school resources approach science inaccurately so I am putting together my own activities. My kiddo insisted on trying it after finding it in a book at the library. I just added enhancements to the activity here and there to optimize his learning.
This activity was great for learning the beginnings of how to document an experiment. I will attach a printable at the end that will streamline the process.
1. To introduce the concept of an acid and a base.
2. To introduce the idea of documenting an experiment.
3. To get hands on experience pouring solutions.
4. To compare before and after
5. To introduce safety equipment and why we use it.
Preparing for the Experiment
1. In a notebook or the printable under the heading Materials, write down all the materials you will need for the experiment (or have the child write them down if old enough). My son read each one out to me and I wrote it in the book.
2. Read over the procedure so you are clear in what you have to do. Under the Procedures heading in point form summarize the procedure to the experiment.
Conducting the Experiment
Collect the following materials:
6 leaves of red cabbage
Transparent cups or jars
A spoonful of baking soda in a little water
Optional: Labels and pen
1. Put on your safety gear if you have it. This was mostly for fun and learning about eye protection. My son wore a lab coat and chemistry googles but long sleeves and sunglasses would do. This is not a dangerous experiment as long as you are mindful of the hot water.
2. Cut the cabbage leafs into pieces or strips. This is done most easily by rolling the leaves and cutting the roll. My son rolled and I did most of the cutting. Place the cut leaves in the large bowl and pour boiling water slowly over them (obviously don't pour near children).
3. Leave the cabbage for 10 minutes. The liquid will turn purple. Carefully strain the liquid into a jug. Discard the cabbage or put it in soup or something.
4. Pour a little bit of cabbage juice into 6 clear cups. You want enough to see the colour of the liquid clearly.
5. Pause for observations. Every time my little guy made an observation, we jotted it down in the book. We took observations at the beginning, during and at the end of the experiment.
6. Label one jar "control" and set aside.
7. Have the child add a bit of lemon juice to one jar, vinegar to another, water to the 3rd, liquid soap to the 4th and baking soda water to the 5th. This is the fun part, they all change colour.
8. Compare the new colours to the control. Compare the acids (lemon juice and vinegar) to the bases (baking soda and soap). Speculate why the water didn't change the colour.
9. We drew a diagram of our results.
Bonus: Try mixing one of the acid jars with one of the base jars. The colour may go back to its original colour (the control) if the acid and base neutralizes correctly.
Here is a template to fill in as the experiment progresses. A notebook works just as well though this version is more colourful and kid friendly.