How to Create a Conductivity Meter
- 1). Cut off an individual bulb from a strand of Christmas lights, using wire cutters. Leave 2 inches of wire on each side of the bulb. Strip about a quarter of an inch of plastic coating off each end.
- 2). Wrap electrical tape around the top edge of a 9-volt battery to insulate the battery and prevent short circuiting.
- 3). Wrap foil around one exposed wire from the light bulb and press the foil wad into the positive battery terminal. Cover it with electrical tape to secure the connection.
- 4). Roll two thin tubes out of aluminum foil to act as your testing probes.
- 5). Press one of the foil leads into the negative terminal of the battery and secure it with tape.
- 6). Wrap the wire from the remaining exposed lead of the light bulb around your second foil lead. Secure this connection with electrical tape.
- 7). Test your conductivity meter by touching the two aluminum leads together. The bulb should light. If it does not, check that all of your wire and battery terminal connections are secure.
- 8). Test the conductivity of a liquid by inserting the two probes into a container filled with the liquid. Make sure the leads do not touch. If the light shines brightly, the liquid is very conductive. Dim or no light indicates a poorly conductive liquid.