Electrical conductor facts for kids
Imagine electricity as tiny particles moving! A conductor is a special material that lets these tiny electric particles, called charges, flow through it easily. This flow of charges is what we call electric current. Most conductors are made of metal, like the copper wires in your house. In metals, tiny negatively charged particles called electrons do most of the moving. In other materials, positive or negative ions can also carry the charge.
When electricity flows in a circuit, it's not like one electron travels all the way from the power plant to your light bulb! Instead, it's more like a line of dominoes. One electron pushes the next, and that one pushes the next, and so on. This chain reaction quickly moves energy through the wire, making your devices work. Metals are great for this because they have many free-moving electrons that can easily bump into each other and pass along the energy.
While electrons are key in metals, other conductors use different particles. For example, batteries use charged atoms called ions in a liquid called an electrolyte. On the other hand, insulators are materials that do not let electricity flow easily, like plastic or rubber. They have very few free charges.
What is an Electrical Conductor?
A conductor is a material that allows electric current to pass through it. This means that electric charges can move freely within the material. Without conductors, we couldn't send electricity from power plants to our homes or power our electronic devices.
How Electricity Flows Through Conductors
The magic of conductors lies in their ability to let charges move. In most metals, tiny particles called electrons are the main charge carriers. These electrons are not tightly held by individual atoms. Instead, they form a "sea" of electrons that can move around.
When you connect a conductor to a power source, these free electrons start to move in a general direction. They bump into each other, passing energy along the wire very quickly. This movement of electrons is what creates an electric current.
What Makes a Material a Good Conductor?
Every material resists the flow of electricity a little bit. This is called electrical resistance. Think of it like trying to run through water – some materials are like thick mud, others like clear water. A conductor's resistance depends on three main things:
- What it's made of: Some materials naturally resist electricity more than others.
- Its length: Longer wires have more resistance. It's harder for electricity to travel a long distance.
- Its thickness: Thicker wires have less resistance. Think of a wide highway compared to a narrow path; more cars (electrons) can pass through easily.
Temperature also affects how well a conductor works. Usually, when a conductor gets hotter, its resistance increases. This is because the atoms inside vibrate more, making it harder for electrons to flow smoothly.
Common Conductor Materials
Many different materials can conduct electricity. The most common are metals. Other types include liquids called electrolytes, special materials like superconductors and semiconductors, and even some non-metals like graphite.
| Material | ρ [Ω·m] at 20 °C | σ [Sm] at 20 °C |
|---|---|---|
| Silver, Ag | 1.59 × 10−8 | 6.30 × 107 |
| Copper, Cu | 1.68 × 10−8 | 5.96 × 107 |
| Aluminum, Al | 2.82 × 10−8 | 3.50 × 107 |
Copper: The Everyday Conductor
Copper is one of the best and most widely used conductors. It's excellent at letting electricity flow. You'll find copper wires inside your home, in motors, and in many cables. It's easy to connect by soldering or clamping, making it a popular choice for many electrical jobs.
Silver: The Best, But Pricey
Silver is actually even better than copper at conducting electricity! It's about 6% more efficient. However, silver is much more expensive. So, it's usually only used in very special equipment, like in satellites, where top performance is needed. During World War II, a huge amount of silver was even borrowed to make magnets because copper was scarce!
Aluminum: Great for Power Lines
Aluminum is another important conductor, especially for long-distance power lines. It's not as good as copper for its size, but it's much lighter and cheaper. This makes it perfect for carrying electricity across vast distances, like from power plants to cities.
However, aluminum has some downsides. It can form a thin layer of rust (oxide) that doesn't conduct electricity well, which can make connections get hot. It also expands and contracts more with temperature changes than other metals, which can loosen connections over time. Because of these issues, aluminum building wiring is not often used inside homes anymore, except for the main power line coming into the house.
Most organic compounds, like plastics or oils, do not conduct electricity. They don't have the free-moving charges needed. But some special organic materials, called conductive polymers, can be made to conduct.
Pure water itself is not a good conductor. But if it has even a tiny bit of salt or other impurities, it can quickly become a conductor. This is why you should always be careful with electricity near water!
How We Measure Wires
Wires come in different thicknesses. Their size is usually measured by how wide their cut end (cross-section) is. In many places, this is in square millimeters. In North America, smaller wires use a system called American wire gauge.
How Much Current Can a Wire Carry?
Every conductor has a limit to how much electricity it can safely carry. This limit is called its ampacity. A wire with lower resistance can carry more current. Thicker wires, which have less resistance, can carry more electricity than thinner ones made of the same material.
If too much current flows through a wire, it can get very hot. This heat can damage the wire's plastic coating, called insulation. If the insulation melts, it can cause a fire. That's why wires are designed with specific ampacity limits to keep them safe. For example, common household wires have insulation that can only handle temperatures up to about 60 degrees Celsius.
Images for kids
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A piece of resistive material with electrical contacts on both ends
See also
In Spanish: Conductor eléctrico para niños
- Electrical cable
- Electrical resistivity and conductivity
- Overhead line
- Stephen Gray, who first studied conductors
- Superconductivity
