Do you have children who love science? Or would you like to have children who love science? A great way to help them develop a love for this subject is by doing science experiments like this easy and fun electricity science experiment.
Science experiments are a great way to let your kids dive into something a little more dangerous than you’d normally allow—such as playing with electricity! Sonlight Science C introduces topics like conductivity and circuits in an exciting tour of Geology, Meteorology, and Mechanical Technology, designed especially for the attention span and skill levels of second through fourth graders. This particular circuit experiment has been adapted from Usborne Book of Science Experiments, Volume Three, a favorite Science C book.
Building a Simple Electrical Circuit
Before we can test whether or not various substances conduct electricity, we first have to create a working circuit.
You can collect the supplies yourself or pull them from two different Sonlight products:
- Thin plastic-coated copper wire
- Small bulb
- Bulb holder
- Three 1.5V batteries (such as AA or AAA)
- A quarter
- A penny
- A galvanized nail
- A small jar
- Other household materials as desired, to test their conductivity
Cut three sections of wire, each approximately nine inches long. Strip the plastic coating off the ends, exposing about an inch of copper wire on the end of each.
Clip two wires securely into bulb holder, as shown. You’ll use the third wire in a moment, but for now, set it aside.
Pick up one of the wires that’s clipped to the bulb holder and place the exposed end flat against the end of a battery. Tape it down securely with masking tape.
Tape two more batteries end to end, creating one long battery. (Make sure there are no gaps, or you’ll break the circuit.) Pick up the remaining wire that’s clipped into the other side of the bulb holder, and tape the end securely to the remaining end of the long column of batteries.
If everything’s touching properly, the bulb will now illuminate.
If not, stop and check all your connections. Are the wires clipped into the battery holder properly? Are the batteries lined up end to end, + to -?
Now that you have confirmed the circuit is working, unclip the wire from the left side of the bulb holder. In its place, clip in the third wire you set aside earlier. (In the photo, the wire which was in the bulb holder is now in the student’s right hand. The new wire which is now in the bulb holder is in the student’s left hand.)
To check this new circuit, touch the wires together. If the bulb lights up, you’re ready for the next step.
Testing the Electrical Conductivity of Household Items
It’s time to put the scientific method to work and make predictions about electrical conductivity! Take a moment to download the accompanying lab chart. First list the substances you plan to test. Then make predictions about whether or not they’ll work to complete the circuit. Will the materials you selected cause the light bulb to glow?
Now, get started testing! Simply touch both exposed wire ends to the material you have chosen, and watch to see what happens to the bulb. Record the results on your printable.
Hint: Since your power source relies on the ability of the masking tape adhesive to keep the batteries touching each other—and to keep the wire touching the batteries—it’s a good idea to periodically check the condition of circuit by touching the exposed wires together. You wouldn’t want to accidentally conclude a substance was non-conductive when the real problem was just a loose bit of tape!
Why Do Some Materials Conduct Electricity Better than Others?
In order for electricity to travel from the power source to the light bulb, it must not be stopped by the test material—it has to be able to pass through and continue through the wire on the other side. A successful circuit is dependent on a fairly unrestricted flow of electrons. If the electrons can find a path through relatively easily, then the material is considered a good conductor.
Did any if your test materials work to illuminate the bulb, but only result in a very dim light? In these cases, the material did allow electrons to navigate through, but not very easily. Material like this doesn’t make a very good conductor.
And if the bulb didn’t light up at all? The electrons couldn’t find a way through!
What Impact Do Variables Have on Results?
Remember, with any scientific experiment, there are always a multitude of variables to consider. As you might have experienced, several things can go awry while testing conductivity. For example, even though a penny does indeed conduct electricity, you might not have been able to illuminate the bulb for several reasons:
- The penny might not have been clean and shiny, so the electricity couldn’t travel through the dirt and residue.
- The wire sections which touch the penny might have been dirty, sticky, or corroded.
- The batteries might not have all been touching each other.
- The wire sections attaching to the bulb holder might have become disconnected.
- The bulb might have been loose, or maybe the filament itself even burned out.
That’s a lot of different variables to troubleshoot, isn’t it? Because there are so many different factors at play, you might get different results than a sibling or friend—and you might even get different results on a different day. This, of course, doesn’t change the science of electrical conductivity, but it does go to show you how precise and exact experiments need to be, doesn’t it? Scientists know they need to make sure their results are repeatable and reproducible, and much of that often comes down to identifying variables.
You can discover more exciting experiments like this circuit activity in Sonlight Science C full curriculum or in Explorations in Science C, both delightful introductions to hands-on exploration and the scientific method.
Sonlight marries the joy of reading with the excitement of hands-on projects to bring you the most complete Science program. Programs are available from kindergarten to college-level lab sciences. Click the image above or click this link to learn more!
Gina Munsey is a Mexico-born, Eastern Europe-raised missionary kid who ended up in Nashville, Tennessee. A blogger for 16+ years, editor, magazine contributor, co-op teacher, and writer who has only completed four chapters of her languishing memoir, Gina spends her days full of coffee and adventures while helping her asynchronous daughter with Chinese homework. You can find Gina at oaxacaborn.com, or in the middle of [home]school surrounded by stacks and stacks of books.