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This page is dedicated for proposals and ideas that may be incorporated in the Eco Sustainable Villages and across the globe. The description must not be more than 250 words giving the basic idea with the author name and time stamped. Although this method is not a substitute for patent and copy rights but may be a safe bank for your ideas and proposals.

Cost effective ideas will be appreciated especially.

For example: Note: The number of words exceeds the limit

however this example shows the economics of the device.

How to detect solar storms under $ 5.

Using a soda bottle

Materials Needed & How to Build It

For teachers, you might involve students, parents, and co-teachers in building several magnetometers at once in assembly-line fashion. There are extensive instructions available on Dr. Sten Odenwald's magnetometer pages.

What You Need

One clean, clear 2-liter soda bottle
1 to 2 pounds of small rocks or other weights
2 feet of sewing thread
One small bar magnet
One index card cut to 2x3 inches
1-inch piece of soda straw (a 2nd piece in optional)

Small rectangular mirror (1" long)
Tape
Meter Stick
Utility knife (use care)
Hot glue gun or Super Glue (use care)
Light source--adjustable desk lamp, or laser pointer with supervision (careful not to direct at eyes)

What To Do

Procedure	Click Images to Enlarge
*Step 1:* Clean and dry the soda bottle and remove the label. Do not discard the cap.
*Step 2:* Use the utility knife to cut a door in the side of the bottle. The hole should be large enough for the index card to fit through. Make sure that the card fits. You can experiment with different types of openings keeping in mind that the opening should not weaken the bottle and
*Step 3:* Fill the empty bottle with small rocks or other weights (e.g. marbles). This is to stabilize the bottle. Be careful not to get the side of the bottle dirty. Sand or other fine material may be used but such materials may cause the mirror to get dusty if the completed magnetometer is moved.
Step 4: Pierce a small hole in the cap.
Step 5: Lead one end the thread through the bottom of the cap. Fasten the short end of the thread to the top of the cap allowing the remainder of the thread to hang from the bottom. Be sure to securely fasten the thread to the top of the cap since the magnetometer's "sensor" will be hanging from that thread. To secure the thread use a knot, tape, glue, or an optional short piece of straw as seen in the picture.
Step 6: Screw the cap onto the bottle allowing the long end of thread to hang down into the bottle. In order to attach the sensor to this hanging string, reach through the hole in the side of the bottle and pull the thread out of the side.
Step 7: Glue the magnet to the center of the top edge of the card.
Step 8: Glue the 1-inch piece of straw to the top of the magnet. The thread will be tied through this straw so that the card can be suspended from the thread.
Step 9: Glue the mirror to the center of the index card. Once it is hung by the thread, the card (with the straw, magnet, and mirror attached) will act as our magnetometer's sensor.
Step 10: Lead the hanging end of the thread through the straw and tie the thread into a small triangle with 1 to 2" sides. Make sure not to leave too much thread for the card to hang from or else it will not be suspended above the weights at the bottom of the bottle.
Step 11: Place the sensor (the card, magnet, and mirror) into the bottle, allowing it to hang freely. If the sensor is hanging too low, pull up on the string at the cap and refasten it. As soon as your magnet is freely suspended, it immediately acts as a compass!
Step 12: Place the bottle on a level surface and point the light source at the mirror. You should be able to see the reflected point of light move on a distant wall or screen as the magnetometer sensor moves. For best results keep the distance between the light source and the mirror less than 1/2 meter, and the distance between the magnetometer and screen at least 1 meter, if possible.

Precautions with Magnets

When working with magnets (especially strong ones), be careful not to bring them to close to other magnetized devices, such as floppy disks, computer hard disks, video and audio tapes, or credit cards. It is also wise to keep magnets clear of electrical currents like those found in computer monitors, TV screens, and some computer equipment. To preserve the life of your magnets, avoid dropping them repeatedly, or keeping them close to other stronger magnets. Both of these actions can demagnetize magnets over time.

How to Take Measurements

How It Works

Along with the magnet, the mirror and lamp are the other important parts of the magnetometer. As you shine a light on the mirror of your magnetometer, that light is reflected off of the mirror onto some distant wall or screen. For small changes in the pointing direction of the magnet, it can be difficult to detect the subtle twisting of the magnet by looking directly at the magnet. However, by following the motion of the reflected light, even small changes in the direction of the magnet's pointing can be detected. In fact, the further away that the screen is from the magnetometer, the more noticeable the side-to-side motion of the reflected spot of light. For that reason, we recommend placing the magnetometer at least 1 meter from the screen or wall on which the reflected light is being projected. To track the horizontal position of the spot of light, attach a ruler to the screen or wall on which the light is being reflected, as in the photo below.

To take measurements with your magnetometer, simply read the location of the spot of light on your reference meter stick or ruler. Data should be recorded in centimeters (cm).

ruler.jpg (8621 bytes)
An spot of laser light reflected from a magnetometer mirror onto a wall.
The location of the spot on the meter stick represents a measurement of 23 cm.

What Is It Measuring?

The soda bottle magnetometer operates on the same principle as a "torsional pendulum" or "torsion balance". What principle is that? It is the simple principle of twisting. The word torsion means "the act of twisting or turning" according to the American Heritage Dictionary. Torsion balances have been used in science to measure very small electrical and magnetic forces. In the soda bottle magnetometer, the hanging sensor (magnet and mirror) will twist whenever a change in the direction of the magnetic field near the magnetometer changes. Any push or pull that causes a twisting of the sensor magnet is a force called a torque, which is related to the word torsion. Because of the hanging magnet's ability to turn easily, the magnetometer allows us to measure very small changes in the direction of the Earth's horizontal magnetic field.

How Can You Tell If It Is Working?

Changes in the direction of the Earth's magnetic field are known to occur gradually over the course of minutes, not rapidly over a few seconds. According to this gradual though measurable geomagnetic behavior, you should expect to see the reflected spot of light move gradually to the left or right as you make measurements, say every five minutes. If the motion of your magnetometer sensor is causing the reflected spot of light to swing back and forth from left to right at a given moment, that motion is likely unrelated to global changes in the Earth's magnetic field. Those rapid movements are more likely the result of vibrations of the building you are in, or a result of rapid local changes in the magnetic field as caused by nearby movement of metal objects (e.g. passing cars or moving elevators).

By global variations in the magnetic field we mean changes resulting from geomagnetic activity, and by local effects we mean nearby variations in the magnetic field that are unique to your local home or classroom environment. Both types of variations are interesting to study, but the global variations can only be confirmed by comparing your measurements with those from a magnetometer in another location.

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