One of my goals with these science videos is to provide support to the homeschool community. After years of writing the Experiment of the Week, and presenting science shows for homeschool groups, I have been impressed with how strongly homeschool families are involved with hands-on science. I have also seen the need for a science curriculum that fulfills their educational needs. Starting with these videos, I hope to offer the homeschool community some of the science education support that they need, as well as a fun way to get students involved with scientific discovery.
I also try to use activities that involve common items. Most homeschoolers don't have access to test tubes, flasks, chemicals, microscopes and other scientific equipment. In the future, I hope to be able to guide them to inexpensive sources for science equipment to enrich their science curriculum.
Anyone that has ever taken a chemistry class or played with a chemistry set is familiar with litmus paper. These little strips of paper change color to indicate whether a chemical is acid or alkaline (a base.) There are other substances that also change color in the same way.
For this experiment you will need:
- the spice Turmeric. This yellow spice can be found in at your local grocery.
- isopropyl alcohol, commonly known as rubbing alcohol
- a disposable plastic cup
- a disposable paper or plastic plate
- coffee filters
- a variety of items from your kitchen. Caution: Household cleaners can be toxic! Be careful!!
Pour about half a cup of alcohol into the plastic cup. Use a disposable cup, as the turmeric will stain it yellow. Put about a teaspoon of turmeric into the alcohol and stir. Be careful not to get this on your skin or clothes, as it will stain them yellow.
Cut several coffee filters into strips about an inch wide and three inches long. Carefully dip each strip into the turmeric mixture and then place them on the disposable plate. Let them dry. They will be bright yellow. It is OK if the part that you are holding does not get have the liquid on it. The liquid is not harmful to your skin, but it will color your skin yellow for a day or so.
Once the paper strips are dry, you are ready to test some substances. Spray a little window cleaner onto one of the strips. It will turn bright red, indication that it is alkaline. Don't worry if several of the strips get sprayed and turn red. In fact, it would be a good idea to spray several of them. Again, let them dry.
Pour a little vinegar into a cup and dip one of the yellow strips into it. Nothing happens. Now dip one of the red strips. It will turn yellow again, indicating an acid. You can test all sorts of foods, to see which ones are acidic and which ones are alkaline or basic. The same strip of paper can change color back and forth many times.
A dramatic variation of this is to bring a piece of yellow turmeric paper near the top of an open bottle of ammonia. The fumes from ammonia are so strong that they change the paper red without any liquid touching the paper. This is a very impressive demonstration.
You can make similar test papers with the juice from red cabbage, blue berries, black berries and other fruits. Some work better than others. It would make an interesting science project to see which fruit papers gave the most dramatic changes.
Have a wonder-filled week.
