[Science] 3rd Grade: The Path of Electricity
Hello everyone!
It's fun to play outside on a nice day, but have you ever thought about how strange it is that the lights turn on instantly just by flipping a switch in your home?
In this chapter, we are going to learn about the secrets of electricity together, specifically: "How can we get a light bulb to turn on?"
It might feel a little difficult at first, but the rules are very simple. Don't worry, we'll take it one step at a time!
1. Let's light up a light bulb!
Imagine doing an experiment using a light bulb, a dry-cell battery, and "wires" to connect them.
To make the light turn on, there is one very important rule.
★ How to connect it so the light turns on
Batteries have a "positive (+) terminal" and a "negative (-) terminal."
To light up the bulb, electricity must flow from the positive terminal of the battery, through the light bulb, and back to the negative terminal. You need to connect everything in a "circle" (or loop).
A complete, unbroken path like this for electricity to flow is called an "electric circuit."
【Point!】
If the circuit is broken anywhere, electricity will not flow.
For example, just like a necklace with a broken string, it won't work if it's falling apart. It’s important to make a solid "loop"!
★ Common mistakes (Check these!)
・Connecting the wire only to the positive (+) terminal of the battery.
・Attaching the wire to the glass part of the light bulb.
*Electricity flows through the "metal" parts of the light bulb. If you attach it to the glass, it won't light up.
2. Things that conduct electricity and things that don't
Let's try placing different objects in the middle of a circuit to see if the light bulb turns on.
In the world, there are two types of things: those that "conduct electricity" and those that "do not conduct electricity."
★ Things that conduct electricity (the bulb lights up)
・10-yen coin (copper)
・Aluminum foil (aluminum)
・Spoon (stainless steel or silver)
・The blade of scissors (iron)
What do these have in common?
The answer is: "metal!" Things made of metal generally conduct electricity well.
★ Things that do not conduct electricity (the bulb does not light up)
・Paper
・Plastic (like a ruler)
・Rubber (like an eraser)
・Glass
・Wood
【Trivia: The secret of cans】
You know how aluminum cans have beautiful pictures and colors painted on them? Actually, if you touch a wire to that paint, electricity will not flow.
But, if you use sandpaper to scrape off the surface so the aluminum (metal) underneath is exposed... look at that! It starts to conduct electricity.
It's not about how it "looks," but what it’s actually "made of" that matters.
3. A closer look at batteries and light bulbs
Let’s learn a bit more about the structure of our tools.
★ Dry-cell battery
・The protruding end is the positive (+) terminal.
・The flat end is the negative (-) terminal.
★ Light bulb
If you look closely at a light bulb, metal is used at the bottom:
・The threaded, screw-like metal part on the side.
・The small, protruding metal point at the very bottom.
If you connect the circuit so that electricity flows through both of these two spots, a tiny wire inside called a "filament" will light up.
【Summary: Remember these!】
1. A path where electricity flows in a "loop" is called a circuit!
2. If a circuit is broken, electricity won't flow!
3. Metal conducts electricity, but materials like paper and rubber do not!
Closing
How was learning about the "path of electricity"?
Just by guessing, "Is this made of metal?" or "Will this conduct electricity?" when looking at things around you, your science skills will grow and grow.
When you use experiment kits or other tools, make sure to check, "Did I make a clean loop (circuit)?" as you go along.
I'm rooting for you!