YOUR OWN ELECTRO-BOARD

ELECTRO-SCIENCE IS MORE THAN BATTERIES, WIRES AND BULBS. SCIENTISTS HAVE BASIC PIECES OF EQUIPMENT THEY USE MANY TIMES IN THEIR EXPERIMENTS. THE ELECTRO-BOARD IS AND IMPORTANT TOOL. IT LOOKS COMPLICATED, BUT IT IS EASY TO PUT TOGETHER. HERE'S HOW.

You need:

1 piece of soft wood, 16 cm x 7.5 cm x 2 cm
5 short screws (#6 x 3/8 self tapping)
4 Fahnestock clips
1 battery holder
1 snap connector for battery holder
an LED
1 33 ohm resistor
2 AA batteries
1 paper card 2 cm x 8 cm
20 gauge wire
a wire stripper/cutter
tape
a screwdriver
a straight pin
a black magic marker

Follow these steps. The pictures will help you.

Make 4 pairs of evenly spaced pinholes down the centre of the card. Mount the LED by pushing its wires through the first pin hole. These wires must not be touching. Use the marker to label the LED 1.
Place the card on the right end of the board
Bend the + wire out one side. Put a big + sign on the board above the card.
Bend the - wire out the other side. Put a big - sign on the board below the card.
Place one Fahnestock clip on each side.
Slide the end of a wire under each clip and use screws to attach them to the board.
Snap batteries into the holder and attach the snap connector. Tape the holder down on the end of the board.
Attach the wire at one end of the resistor and the bare end of the black wire both to the board with the same screw.
Use another screw and a Fahnestock clip to fasten the other end of the resistor down. Put them on the same side of the board as the - LED wire. Label this clip with a B.
Now, use a screw and Fahnestock clip to attach the bare end of the red wire to the + side of the board. Label this clip A.

HERE IT IS — YOUR ELECTRO-BOARD!

Finally, test it. Experiments and scientists always check out their equipment.

Cut two short wires and bare the ends. Attach one end of each to these Fahnestock clips. That connects them to the battery.
Now, place the free end of each wire into the two clips for the LED to check your circuit. It should glow as you complete its circuit. If not, make sure that the batteries are sitting properly in the holder, that everything is connected and that the LED is in the right way.

CONNECTIONS

None.

CHALLENGE

None.

FLASH FACT

None.

TEACHER'S NOTES

This project results in a handy tool that assembles and holds a collection of electrical components. The electro-board is a necessary part of most of the activities that follow. The wood block only has to hold everything in place. its size and shape are not important. The paper card is a holder for the LED. Since there will be three more, spread the pin holes down the card so that the LEDs will be evenly spaced out.

The resistor increases the life of batteries by reducing the flow of electrons to the LEDs. It also prevents heating if you accidentally create a short circuit.

The resistor must be used to reduce the flow of electrons to the LED. LEDs are easily destroyed if too many electrons are allowed to flow. Use two AA batteries only, otherwise LEDs would likely burn out. LEDs come in many shapes and sizes. If you want to try out some different ones, get assorted LEDs.

Sometimes it is difficult to tell which LED wire is "+" and which one is "-". If so, trial and error works because it lights only when it is connected correctly. Also "-" is from the battery and "+" is to the battery. Start the holes in the board with a nail to help the screws go in easier.

Students should have had the opportunity to practice with wire strippers. They need to learn how to remove the insulation without cutting through the wire. Electrons can flow either way through a resistor, so it doesn't matter which way around it is connected.

Snap connectors have colour coded wires. Red is "+". Black is "-".