Applied Science - Technology (4B) Pre Lab
 OBJECTIVES: Comparing magnetism and electricity. Investigating electromagnetism. VOCABULARY: electricity electromagnetism magnetic field magnetism MATERIALS: worksheet magnet (demonstration) Students use a worksheet to explore magnetism and electricity.
 BACKGROUND: How are electricity and magnetism related? This was a problem that many researchers in the early 1800's were trying to discover. Michael Faraday discovered how to convert magnetism into electricity in 1831. This bookbinder learned to read the books he was binding and became fascinated with chemistry and physics. Sir Humphry Davy of the England Royal Institute was impressed when Faraday presented Davy with a book of notes that Faraday made of Davy’s lectures. Faraday later succeeded Day as Director of the Royal Institute. Faraday coined the words electrode, anode, cathode, electrolyte, and ions which are used to this day. Faraday developed a continuous mechanical motion produced by electrical current (a motor) in 1821. He also developed the first electric generator, and realized that light is an electromagnetic in nature because it can be deflected by polarized light with a magnet. PROCEDURE: This exercise illustrates Faraday's Law which states that "the induced voltage in a coil is numerically equal to the product of the number of loops and the rate at which the magnetic field changes within those loops". This can be used to demonstrate the practical side of multiplication.    When electricity flows through a wire, the electricity produces a magnetic field. By inserting a core of iron or steel, the magnetism is intensified. The wire coil wound around a core is called an electromagnet when it completes a circuit. Electromagnets are temporary, but used in transistor radios, doorbells and electric motors. Students will be making an electromagnet in lab. The worksheet will help them to understand why you need to increase the number of coils around a wire.    Use the worksheet to go through the process of increasing the strength. An electric current can also be made to flow in a wire by simply moving a magnet in or out of a coil of wire. This is called "electromagnetic induction". You could illustrate this with your students with a similar set up as the worksheet, but it is sometimes difficult to see if you do not have the correct meter.    ANSWERS: 1.  one 2.  two 3.  three