Sample Magic Fields and Poles (grades 3-4) Worksheet
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Magic Fields and Poles
By Trista L. Pollard 		  
1     When you hear the word "field", you may think of baseball, corn, or soccer. However, there are also invisible fields called magnetic fields. A magnetic field is the space around a magnet where the force of the magnet can be felt. This field of force is the reason magnets can attract steel and iron objects without touching them. Although you cannot actually see this field of force, you can tell it exists based on how iron and steel objects react to a magnet from a distance. For example, if you place a small paper clip near a magnet, it will start to move toward the magnet almost like "magic".
 
2     Magnets come in different shapes and sizes. Common shapes are bars, letters (v and u), horseshoes, and cylinders. The field of force for all magnets surrounds the entire magnet and is strongest at the poles or ends of the magnet. Magnets that are shaped like U'S, V'S, or Horseshoes are more powerful than other types of simple magnets. Since these magnets are bent, two poles are used to attract objects instead of one pole like a bar magnet. How do we know where the field of force ends? Well, the field of force around a magnet goes on for an infinite distance or beyond where the human eye can see. So, for our study we could say that a magnet's field of force ends when we are no longer able to see it attract objects like a paper clip. Now for a little magic!
 
3     Put a paper clip in the palm of your hand. Now try holding a strong magnet against the back of your hand. What do you think will happen? Well, if you said the paper clip will move, you were right. Magnetic fields of force can go through many types of materials, like your hand, without losing their power of attraction. Those materials and your hand are "transparent'' to the magnetic field's lines of force. When an object is transparent, you can see through that object. Well, for a magnet, this means that its power of attraction can go through your hand and attract an iron or steel object within its field of force. Now you understand why people can wear magnetic earrings on their earlobes. Plumbers also use this knowledge about transparency and magnetic fields to help them locate iron pipes in closed walls. Iron and steel, however, are opaque to a magnetic field's lines of force. You are not able to see through opaque objects. Therefore when a magnet touches iron or steel, the force passes to the inside of the objects and back into the magnet causing an attraction.

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