BATTERY - POWERED MINI FAN

OBJECTIVE:

Four-Hers and youth will learn the concepts of open and closed circuits and storage and usage of dry cell power through the construction of a hand held mini fan.

SKILLS LEARNED:

Soldering electrical connections.
Use of a hot glue gun to attach wire or other materials to larger objects.
Understanding of basic electric circuits and the direction of electron flow.

TIME:     One and one half to two hours for a group of twenty youth.

INSTRUCTOR NEEDS:

One project leader and three or four adult or teen leaders

PARTS LIST:
1 plastic battery clip
1 electric motor
1 roll of copper wire
1 plastic propeller
1 foot per youth of clear plastic tubing cut into three inch long pieces

COST:     $2.00

TOOLS & SUPPLIES:
6 to 8 soldering irons
6 to 8 hot glue guns
2 to 4 electrical power strips 2 extension cords
1 roll rosin core solder
1 package of hot glue sticks
3 pieces of copper wire: two 2 1/4 inch strip and one 1 1/4 inch strip
1 knife sharp enough to cut through plastic tubing
Burn spray

ASSEMBLY PROCEDURE:

Divide youth into 2 to 3 people at each station. (One station consists of a soldering iron and a hot glue gun.) Start assembly as shown below.

A. WIRE AND MOTOR ASSEMBLY

1. Take one 2 1/4 inch wire and slip it through the hole in one of the motor's tabs (figure A1) and  make a hook (figure A2), then close the hook (figure A3).
   
   
2. Now do the same thing with the 1 1/4 inch wire through the other tab.
   
   

B. BATTERY CLIP AND WIRE ASSEMBLY

1. Take the 2 1/4 inch wire that you have left and slip it through the large hole in the middle of the  unspringed end of the battery clip (figure C1). Again, you will want the wire through the hole just  far enough to make a hook (figure C2).
   
   
2. Wrap the long end of the hook around the short end one time (figure C3).
   
   
3. Bend the short piece back (if possible) and pull the long end up the back of the clip as far as  possible (figure C4).
   
   
4. Take hold of the hot glue gun and squeeze a dab of hot glue half way up the wire. Wait 15 to 20 seconds for the glue to cool, then press the end of the wire to the clip so the wire will be firmly attached (figure C5).
   
   

C. BATTERY CLIP AND MOTOR ASSEMBLY

1. With the battery clip in hand, pull back through the spring the short wire (soldered to the motor) through the big hole in the springed end and out through the first and second spring (figure D1). 
   
   
2. Bend the short wire over the top and off to the side (figure D2a). Pick up the hot glue gun and squeeze a dab of hot glue at the point where the wire and spring touch each other (figure D2b).
   
   
3. If it is not already, the long wire attached to the motor needs to be positioned on the back of the battery clip. This can be done by slowly twisting the motor until the two long wires are aligned (figure D3)
   
   

D. FORMATTING THE CIRCUIT

1. Make a small, L - shaped bend (or as close as possible) in the long wire attached to the motor (figure E1). Now bend the wire away from the clip (figure E2).
   
   
2. Hot glue this wire to the clip, just as you did with the other long wire. Do not, however, put glue anywhere near the area where the two wires touch each other (figure E1).
   
   
3. You have now created a switch that will turn your fan off and on. When the two wires are pressed together, a closed circuit is formed and electricity flows from the battery to the motor, which then rotates the propeller. When you release the wires from one another, an open circuit is formed and the fan will stop. (If it does not increase the angle between the "L" and the clip (figure E2).
   
   

F. TEST FAN

1. Insert an AA battery into the clip and press the wires together. If the fan is sucking in air instead of blowing it out, take your battery out and flip it over. The battery clip is not polarity sensiffve, so there can be a negative to positive flow of electricity regardless of how the battery is put in.
   
   
2. Take the propeller off and cautiously slip the fan assembly inside the plastic tubing up to the point where the motor reaches the tube. Then gently hug the motor inside the tube about 1/4 of the way. Any more than this, and you risk not being able to get your fan assembly out of the tube to replace the battery (figure F1).
   
   
3. You can complete the circuit by pressing on the tube over the area where the two wires touch.

BASIC ELECTRICAL CONCEPTS:

Circuits and electron flow.

AC/DC current

Different types of energy: Chemical and electrical (battery), mechanical (motor), and wind (propeller)