Students will be able to use the equipment provided to experience and understand the relationship between magnetic and electric fields. Students will also observe basic circuitry and the difference between conductors and insulators.

Associated Standard and CORE Objectives:

• 3050-05      - Students will relate how electricity affects daily lives.
• 3050-0501 - Compare ways of generating and using electricity. Identify and describe different ways electricity is generated.
• 3050-0502 - Construct models of circuits.

• 1 - Circuit board
• 1 - Faraday's Induction Coil
• 1 - Large electric motor and adapter
• 1 - Plasma ball and neon tube
• 2 - Magnetic field tubes
• 1 - Strong (horseshoe) magnet & steel rod
• 2 - Conductor/insulator wands
• 3 - Compasses
• 6 - Bar magnets
• 2 - Hand crank flashlights/generator
• 3 - Cow magnets
• 1 - Extension cord
  
  

Strong Magnetic Fields: Student tries to put the metal rod between prongs of the strong (horseshoe) magnet without touching the sides. Students then puts the metal rod across the prongs of the magnet.

Notice it is very difficult to remove the rod perpendicularly (straight out) from the magnet. It is easier, however, to slide it out parallel (off of) to the magnet.

Magnetic field tube: Students can insert a cow magnet into the tube. Observe the filings reaction to the magnetic field. Hold magnet still.

The magnetic field is three dimensional and forms a spherical shape around the magnet much like the skin on an apple.

Bar Magnets and Compasses A compass is a very sensitive magnet. Using the bar magnets the students can see how magnets are attracted to, or repelled from each other.

They can also see how the compass needle will point toward one end of the magnet, and point the other direction when the other end is brought near the compass.

Students can also observe how the compass will point north when no other magnets are near the compass.

NOTE: Please store compasses and magnets in separate containers when putting materials away.

Faraday’s Induction coil, connected to meter: Wave a cow magnet through the center of the loop. Notice that the meter detects the magnet. The moving magnetic field will cause a current of electricity in the loop.

The direction of the electricity will change depending on the direction the magnet is going. Make sure the students realize that there is no power source.

Hand Crank Flashlights: Students can squeeze the flashlight handle and see the light bulb light up.

They can see that the faster they squeeze the handle, the brighter the light bulb will shine.

They can also observe the interaction between the magnet’s poles and the coils of wire and realize that electricity is being produced.

Large Electric Motor: Students can turn on the switch on the motor to see it move. See attached station label for description.

Students can also use one of the compasses to see that the two stationary coils become magnetized when the power is turned on.

Plasma Ball and neon tube: High voltage (30,000 volts) is distributed to the inner ball. The charge will be transmitted from this inner ball to the outer ball. The outer ball contains a gas that glows when electricity passes through it.

The plasma ball is very similar to the way storm clouds in the atmosphere become charged to a different level than the earth and eventually will transmit that charge to the earth as lightning.

In the Plasma Ball, electrical transmission will go from the inner ball to your fingers (when the glass is touched) because your body is at a lower potential than the inner ball charge. In other words, the hand is the nearest pathway that the spark can travel or discharge through to the ground. The neon tube likewise has a gas in it that glows when electricity flows through it.

If a student carefully holds the neon tube against the plasma ball, the tube will glow but only up to where the student is holding it (so if a student holds it in the middle, only half of the tube will light up).

The electricity is flowing through the tube to the student. This shows how static electricity works. Static electricity is how scientists first learned to use electricity.

The Plasma Ball is extremely fragile; please have students handle it with care. Make sure that the wires on the DC motor do not come together, it will make a spark.

Caution students to avoid placing their fingers between the strong magnet and the steel rod. Computers, pacemakers or other medical, electronic equipment can be adversely affected by the Plasma Ball and the magnets.

Career Fields:

Science, Technical

Occupations:

• Civil Engineer: Plan, design, and oversee the construction and maintenance of roads, railroads, airports, bridges, harbors, channels, dams, irrigation projects, pipelines, power plants, and water supply and sewage systems. They may work in areas of design, research, construction, or teaching.

Education: Bachelor’s Degree

• Electrical Engineer: Design, develop, test, and supervise the manufacture of electrical and electronic equipment. Electronic equipment includes power generating and transmission equipment used by electric utilities, electric motors, machinery controls, and lighting and wiring in buildings, automobiles, and aircraft. Electronic equipment includes radar, computer hardware, and communications and video equipment. Education: Bachelor’s Degree

• Electrician: Install, connect, test, and maintain electrical systems for a variety of purposes, including climate control, security, and communications. They may also install and maintain the electronic controls for machines in business and industry. Education: 4-5 year apprenticeship

• Mechanic: Inspect, maintain, and/or repair electrical systems for automobiles and light trucks with gasoline engines, such as vans and pickups. Education: Varies from on-the-job training to Associates Degree

* Taken from Occupational Outlook Handbook 1998-1999.

1. What happens when a magnet passes through Faraday’s Induction coil or any coil of conducting wire?
2. Is something similar happening when you squeeze the handle on the hand cranked flashlights?
3. What materials make good conductors? Which ones are poor conductors?
4. What affect does resistance have on electricity flowing through a circuit?
5. What happens when a built up of excess, out-of-balance positive or negative changes?