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.
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One of the writing exercises that has helped me over the years is a very simple, but very powerful one. You simply pick a place and sit there, relaxed and looking around. If you sit long enough, you will start to notice things that you never really thought about before. This experiment was the result of sitting on the beach, and watching the waves on the shore. As I watched, all sorts of questions popped into my mind, but this one really stood out. Why does adding clear water to dry, white sand make it look darker?
To find out, you will need:
- a paper towel
- water
- a bright light
Lay the paper towel on the table and place a drop of water in the center. Notice how the paper darkens as the drop expands. Have we changed the paper? If you let it dry, you will see that the paper is still the same color. It is only dark while it is wet.
Next, lift the paper and hold it between you and the light. This time, the wet spot looks brighter than the rest of the paper, instead of darker. This is the clue we need to answer our question.
Understanding the Science
Lets start with the paper towel. Before it gets wet, it looks white because it is reflecting most of the light that hits it. The light hits the paper, and is reflected back to your eye. A black piece of paper looks black because it absorbs most of the light. Not much bounces back to your eye, so it looks dark.
When the paper is wet, the water fills in some of the spaces between the fibers. This water acts just like a fiber optic cable, carrying the light through the paper instead of reflecting it back to your eye. Since more of the light goes through the paper, less of the light is reflected back and the wet spot looks darker. That is also why the wet spot looks brighter when you hold the paper between you and the light. You are seeing the light which would normally be reflected back from the other side of the paper.
The same thing is true for wet sand, wet clothes, etc. That brings up another good question. Could you get a suntan or sunburn through wet clothing? Sounds like a good science fair project to me.
Have a wonder-filled week.
