February+Electricity+Lab

Electricity and magnetism are closely related. Electricity flowing through a coil can magnetize a steel bar or iron nail and create an **electromagnet**. The magnetic field of a wire can be made stronger if the wire is wound around in a coil. When the current is passed thought the coil, the coil behaves like a bar magnet and is called a **solenoid.** The region inside the coil is called the **core.**
 * Creating an Electromagnet Lab (Background Information)[[image:file:///C:/DOCUME%7E1/pdougla/LOCALS%7E1/Temp/msohtmlclip1/01/clip_image002.gif width="84" height="84"]]**

If the solenoid has a rod of a soft ferromagnetic material such as iron placed inside it, the rod is quickly magnetized and adds its own magnetic field to that of the solenoid. Together the solenoid and the ferromagnetic core can make an **electromagnet**.


 * Magnetism** is an invisible force that attracts some metals, especially iron and steel. Materials that create this force are said to be **magnetic** and are called **magnets.**

If you float a magnet in water or hang it from a thread tied around its middle, it will always point in a north-south direction. The part of the magnet that points north is the **north** or **north-seeking pole.** The other is the **south** or **south-seeking pole**. A north and south pole of a magnet will pull toward or **attract** each other. Two south poles or two north poles will push each other away. This is called **repulsion**.
 * Poles**

Materials that can easily be magnetized (turned into magnets) are called **ferromagnetic.** They can be described as hard or soft. Soft ferromagnetic materials such as iron will quickly lose their magnetic properties. Magnets made from these materials are called **temporary magnets.** Hard ferromagnetic materials such as steel keep their magnetic properties for much longer. These are used to make **permanent magnets**.
 * Types of Magnets**

When a chain of paper clips is picked up by a magnet, each paper clip in this chain has become magnetized by contact with the magnet. Each is a temporary magnet. If the magnet is removed, the clips will lose their magnetism.

A compass is a permanent magnet. It points to the Earth’s magnetic poles.


 * Dipoles and Domains**

A ferromagnetic material has molecules which behave like tiny magnets. They are known as **dipoles** and are grouped in **domains**, in which they all point the same way. When the material is magnetized, all domains become ordered. The material loses its magnetism if its domains become jumbled up again. Ordered dipoles collectively form a magnet, but individually, each one is trying to flip around, as its poles are attracted to the opposite poles of the whole magnet. As they turn, the magnet loses its magnetism.


 * Magnetic Fields**

The region around the magnet in which objects are affected by its magnetic force is called a **magnetic field.** The strength and direction of the magnetic field are shown by magnetic flux lines. The magnetic field is strongest where the lines are close together. The lines are closest near the poles of a bar magnet, where the field is the strongest.

The Earth itself is a magnetic field. It acts as though it has a giant bar magnet through its middle. The north pole of a compass points toward a point called **magnetic north**, its south pole points to **magnetic south**. These are different from the geographical North and South Poles.

To see magnetic flux line, sprinkle some iron filings onto a sheet of clear plastic or a piece of white paper, then hold a magnet underneath. The iron filings will move to show the pattern of the magnetic field.



Magnetic File Lines formed from a bar magnet.

These magnetic flux lines show the direction of the magnetic field around the Earth.

__ Simple Electrical Circuits- vocabulary __
 * __Circuit__** - a path that follows a curved course and finishes at the point at which it began.
 * __Electrical circuit__** - a route around which an electrical current can flow, beginning and ending at the same point.


 * __Battery-__**[[image:file:///C:/DOCUME%7E1/pdougla/LOCALS%7E1/Temp/msohtmlclip1/01/clip_image009.gif width="73" height="73"]] a number of connected electric cells that produce a direct current through the conversion of chemical energy into electrical energy.


 * __Current__** - the flow of electricity through a cable, wire or other conductor.


 * __Wire-__** a strand of metal, usually copper, that is encased in plastic or another insulating material and is used to carry an electrical current.
 * __Bulb-__**[[image:file:///C:/DOCUME%7E1/pdougla/LOCALS%7E1/Temp/msohtmlclip1/01/clip_image011.gif width="59" height="73"]] the same as a light bulb - A near –spherical glass case containing a filament that emits light when an electric current is passed through it. The filament is made from a type of strong metal, tungsten, and is surrounded by the gases argon or neon.

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