|
Here's an experiment that you can do to get an idea of how electrical logging works. You can investigate the resistivity of dry ground and ground soaked with different liquids.
- several paper or plastic cups
- a measuring cup
- sand, soil, or fine gravel
- water
- salt
- lubricating oil or vegetable oil
- an ohmmeter
- six pieces of stiff bare copper wire, each about 10 cm (4 in.) long.
- Fill three cups with equal amounts of dry sand, gravel or soil. Label the cups A, B, and C
-
 Mix up some saltwater in the measuring cup. Use about 30g of salt to 200 ml of water.
- Pour the saltwater into cup A until the sand is saturated. If you don't have enough saltwater to thoroughly soak the sand mix up some more as you did in step 2. You should add enough water to thoroughly soak the ground, but not so much so that there is a puddle of water on the surface. If you pour too much, soak up the excess with a sponge or paper towel.
- Saturate the sand in cup B with oil.
- The sand in cup C should remain dry.
- Insert two wires into the sand in each cup. They should be about 2 or 3 cm (an inch or so) apart. They should be buried well into the sand, but with the ends sticking out above the surface.7. Touch the ohmmeter probes to the two wires sticking out of the dry sand. Record the resistance. Do the same with the salt water saturated sand and the oil-saturated sand.
Record your results on a table like the one below. Fill in the blank spaces in the second column.
|
Things To Do
Science Center
Schools
SEED People
