Does the color change more if you add more test material?.Try another material in the next container. Does the color of the liquid change? Have fun admiring the wild colors you can make. Mix in about a Tablespoon of one of the testing compounds into one of the containers and label it. Pour about 1/3 cup of the red cabbage juice into testing containers such as clear glasses or plastic cups. Pour the batches together in a pitcher (which can be placed in the refrigerator for use later in the day if necessary.) You can also strain the slurry through a strainer to remove the solids. Simply grind up the fresh red cabbage leaves in small batches with just enough water to allow the blender to work properly. Some recipes call for boiling the cabbage but that is smelly and unnecessary. If you are really tired of red cabbage, try the juicing beets (the root part), or berries instead.Īll you need is red cabbage from the grocery store and a blender. Using red cabbage as a pH indicator works well for an activity with mixed-age groups because each age may achieve a different level of understanding. Even if you have done it before, pull it out again and try something new with it.
If you haven’t done this, it really is fun. I know, I know, red cabbage indicator is all over the Internet and has been probably over-exposed, but that is because it is easy and works for both acids and bases. A nthocyanins- derived from red or purple fruits and berries, such as: red cabbage! Pool supply and aquarium supply stores may also carry it.Ģ. Litmus paper is available online or in science supply stores. If neither changes, the substance you are testing is neutral. If the red (pink) litmus paper turns blue, it is a base. If the blue litmus paper turns red, it is an acid. All you need to do is dip the litmus paper strip into the liquid to be tested. Litmus paper is a classic for exploring acids and bases. Litmus is a complex of dyes extracted from certain lichens. Examples of pH indicators from plants include:ġ. Label each container when you add a substance to be tested so you remember which is which.Ĭertain molecules and substances change color when exposed to specific acidic or basic conditions, and thus can be used as pH indicators. Gather small clear containers such a plastic cups or clean baby food jars to carry out the experiments in. Also, adding vinegar to baking soda is fine, but do not mix strong acids and bases. Note: Bleach doesn’t work well because it interferes with the dye molecules. Baking soda (mix with water to moisten)Īdd any other household materials you might be curious about, but only under adult supervision.Gather at least some of the following possible acids or bases to test:
Although no one knows for sure how the name pH came to be, it is acceptable to think of pH as the “power” of hydronium ions, or “how many hydronium ions are present.” (Hydrodium ions are technically H 3O + ions, but are often written as H +.) It is a logarithmic scale, which means that lower numbers, like 1 or 2, indicate a larger number of hydronium ions, and that a substance is more acidic. Note: Scientists know: never taste, drink or eat anything from a science experiment!Ĭhemists have created a scale to measure how acidic or basic a substance is, called the pH scale. People have known for centuries that acids: For this lesson we are going to look at three different classes of plant chemicals that can be used to study the pH of acids and bases. Plants contain an encyclopedia of different chemicals, which they use for growth, communication, and defense. Today we’ll look at chemicals found in plants for Chemistry Week. Each Tuesday we generally celebrate plants with “Seed of the Week” posts.
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