| This article teaches kids about chemistry and is an | | | | gloves (latex or similar) and eye protection (safety |
| excellent introduction to the totally fun activities in | | | | goggles), and if you're not sure about an experiment or |
| homeschool chemistry (including exothermic reactions, | | | | chemical, just don't do it. (Skip the peroxide and cold |
| phase shifts, and acid indicators). It's also good for boy | | | | pack if you have small kids.) |
| scouts working on a badge, or for any kids that love | | | | What about the red cabbage? Red cabbage juice has |
| science experiments. These experiments are part of a | | | | anthocyanin, which makes it an excellent indicator for |
| homeschool science program that I teach, and I | | | | these experiments. Anthocyanin is what gives leaves, |
| promise your kids will love it. | | | | stems, fruits, and flowers their colors. Did you know |
| Chemistry is an exciting subject for kids of any age, | | | | that certain flowers like hydrangeas turn blue in acidic |
| especially if you set up a natural discovery | | | | soil and turn pink when transplanted to a basic soil? |
| environment for them to safely explore in. Let's find out | | | | This next step of the experiment will help you |
| how to do this with your own homeschool science | | | | understand why. You'll need to get the anthocyanin out |
| learning environment. At a university, one of the first | | | | of the cabbage and into a more useful form, as a liquid |
| things you will learn about in your chemistry class is the | | | | "indicator". |
| difference between physical and chemical changes. | | | | Prepare the indicator by coarsely chopping the head |
| An example of a physical change happens when you | | | | of red cabbage and boiling the pieces for five minutes |
| change the shape of an object, like wadding up a | | | | on the stove in a pot full of water. Carefully strain out |
| piece of paper. If you light the paper wad on fire, you | | | | all the pieces (use a fine mesh strainer) and the |
| now have a chemical change. You are rearranging the | | | | reserved liquid is your indicator (it should be purple). |
| atoms that used to be the molecules that made up the | | | | When you add this indicator to different substances, |
| paper into other molecules, such as carbon monoxide, | | | | you will see a color range: hot pink, tangerine orange, |
| carbon dioxide, ash, and so forth. How can you tell the | | | | sunshine yellow, emerald green, ocean blue, velvet |
| difference between physical and chemical changes? | | | | purple, and everything in between. Test out the |
| There's an easy way to tell if you have a chemical | | | | indicator by adding drops of cabbage juice to |
| change: if something changes color, gives off light (like | | | | something acidic, such as lemon juice and see how |
| the light sticks used around Halloween), heat is | | | | different the color is when you add indicator to a base, |
| absorbed (gets cold) or produces heat (gets warm). | | | | like baking soda mixed with water. |
| Some quick examples of physical changes include | | | | Have your indicator in a bottle by itself. Old soy sauce |
| tearing cloth, rolling dough, stretching rubber bands, | | | | bottles or other bottles with a built-in regulator that |
| eating a banana, or blowing bubbles. Shopping List: ? | | | | keeps the pouring to a drip is perfect. You can also |
| Rubbing alcohol (largest bottle) ? Hydrogen peroxide | | | | use a bowl with a bulb syringe, but cross-contamination |
| (largest bottle) ? Baking soda (largest box you can | | | | is a problem. Or not - depending if you want kids to |
| find) ? Distilled white vinegar (largest size) ? Washing | | | | see the effects of cross-contamination during their |
| soda (near the laundry soap) ? Citric acid (optional, but | | | | experiments. (The indicator bowl will continually turn |
| nice to have) ? One head of red cabbage ? Clear | | | | different colors throughout the experiment.) |
| ivory dish soap (small bottle) ? Alum (check the spice | | | | Your mission: To find the reactions that generate the |
| section) ? Single-use cold pack (not the gel kind) ? | | | | most heat (exothermic), absorb the most heat |
| Plastic zipper bags and old water bottles ? Muffin cup | | | | (endothermic), and which are the most impressive in |
| baking tray (12 cups or more) | | | | their reaction (the ohhhh-ahhhhh factor). |
| Let's mix up chemicals that bubble, ooze, freeze, and | | | | The Experiment: Start mixing it up! When I personally |
| change colors. Before we start, you'll need to get | | | | teach this class, let them have at all the chemicals at |
| these items together: a muffin cup baking tray, water, | | | | once (even the indicator), and of course, this leads to a |
| vinegar (acetic acid), baking soda (sodium bicarbonate), | | | | chaotic mix of everything. When the chaos settles |
| washing soda (sodium carbonate), rubbing alcohol, | | | | down, and they start asking good questions, I reveal a |
| hydrogen peroxide, citric acid, ammonium chloride (don't | | | | second batch of chemicals they can use. (I have two |
| activate the cold pack, but instead cut open and | | | | identical sets of chemicals, knowing that the first set |
| empty the contents into a plastic bag and discard the | | | | will get used up very quickly.) |
| water pouch inside), aluminum sulfate ("alum" in the | | | | Tip for Testing Chemical Reactions: Periodically hold |
| spice section of the grocery store or drug store), a | | | | your hand under the muffin cups to test the |
| head of red cabbage and a clear liquid dish soap such | | | | temperature. |
| as Ivory. | | | | After the initial burst of enthusiasm, your homschool |
| Cover your kitchen table with a plastic tablecloth (if | | | | science students will intrinsically start asking better |
| you have small kids, put another tablecloth on the floor | | | | questions. They will want to know why their green goo |
| to catch the spills). Place your chemicals on the table. | | | | is creeping onto the floor while someone else just |
| A set of muffin cups make for an excellent chemistry | | | | bubbled up hot pink, seemingly mixed from the same |
| experiment lab. (Alternatively, you can use empty | | | | stuff. Give them the change to figure out a more |
| plastic ice cube trays.) You will mix in these cups. | | | | systematic approach, and ask if they need help before |
| Leave enough space in the cups for your chemicals to | | | | you jump in to assist. |
| mix and bubble up - don't fill them all the way when | | | | Homeschool Science Teaching Tips: You can make |
| you do your experiments! | | | | this lab more advanced by adding a postage scale (to |
| Set out your liquid chemicals in easy-to-pour containers, | | | | measure the solids in exact measurements), small |
| such as water bottles (be sure to label them, as they | | | | beakers and pipettes for the liquid measurements, and |
| all will look the same): alcohol, hydrogen peroxide, | | | | data sheets to record temperature, reactivity, and acid |
| water, acetic acid, and dish soap (mixed with water). | | | | base indicator levels. Hint - make the data sheet like a |
| Set out small bowls (or zipper bags if you're doing this | | | | matrix, to be sure you get all the possible combinations. |
| with a crowd) of the powders with "scoopers" made | | | | Use the indicator both before and after you mix up |
| of the tops of your water bottles. The small | | | | chemicals, and you will be surprised and dazzled by |
| "scoopers" regulate the amounts you need for a | | | | the results! |
| muffin-sized reaction. Label the powders, as they all | | | | ________________________ As a teacher, |
| look the same. | | | | homeschool science teacher, engineer and university |
| Although these chemicals are not harmful to your skin, | | | | instructor Aurora Lipper has been helping kids learn |
| they can cause your skin to dry out and itch. Wear | | | | science for over a decade. |