One of my greatest tendencies in homeschooling is in just skipping over all those science experiments that are included in our curriculum. Let’s face it. Science experiments can take a lot of time. They can be a big mess. They don’t always produce the results that they are meant to. But most of all, I am sad to report, that science experiments are the things that kids love the most, make science become real, and create a whole lot more learning sometimes than was ever intended.
Yesterday, the boys and I experienced this very thing. We have been doing a full year of ocean studies. Our current topic is all about sharks and rays. Now that seems pretty elementary, but you would be amazed at the things we have been learning about in using Apologia’s Zoology 2 Book.
The main idea that had been presented in the book and highlighted in our experiment was a feature of sharks called the ampullae of Lorenzini. These nerve receptors detect electricity in the water which allows them to detect the location of other creatures and food sources. It is really quite amazing if you think about it.
So what did we do?
I was so thoroughly intrigued by the conversations that we entered into. The first step in our experiment was for the boys to connect a 6V battery to a lightbulb and two nails. Just in building this contraption, the boys learned about:
- Closed versus open circuits
- Metals as conductors of electricity
- The role of the insulated plastic on wiring is to prevent grounding
After getting everything connected, we then put the nails in a glass of distilled water with the nails not touching. In doing this, the lightbulb that became lit when the nails were touching out of the water would no longer come on. The boys then talked about how the circuit was no longer closed and that the electricity wouldn’t pass through the water.
The final step in the experiment was to add about 2 tablespoons of salt to the water and then to see if the lightbulb would light if the nails were placed back in the water. To their amazement, the lightbulb shown brighter than at any previous time. They noticed that the water started moving as if it were boiling. And our final observation was that the water at the top of the glass was turning a copper color.
So our little experiment to learn about the detection of electricity in the ocean by the shark’s amupllae of Lorenzini really revealed a lot more. It demonstrated to us:
- That electrical current in the water can actually produce movement in the water
- That the transformation of the water from translucent to copper color was due to the ionizing of the metal in the nails.
- That basic salt has positive and negative ions that can act as conductors of electrical current.
So the next time you are tempted to skip those time-consuming and messy science experiments, just remember that there might be more learning that goes on during this hands on application of science than reading a much larger textbook assignment. I am sure that my boys will not soon forget our afternoon together.
They asked for me to share with my readers that if you ever have a burning desire to go swimming during a thunder and lightning storm that you are safer swimming in a fresh water pond than the ocean! Their hypothesis was upheld!