| time
requ.: |
10 minutes. |
|
objective: |
characteristics of materials,
test on conductivity |
| material: |
- power supply or
- battery 4,5 V
- lamp with bulb ~4,5V
|
- 2-4 crocodile clamps
- multimeter (current)
- 4 cables with banana plugs
|
| chemicals: |
- tie of magnesium
- wire of copper
- strips of different metals
- chalk
|
- piece of aluminum foil
- rusty spike of iron
- rock
- wood(en pencil)
|
|
procedure: |
Build the electrical circuit according to the sketch (power supply: position 0). Multimeter: use the highest position
for current (10 or 20A). The voltage of the power supply should not
exceed the voltage of the lamp. Test for function without test material
(resistor R).
Put the different materials
as a resistor R between the crocodile clamps and increase the voltage slowly to the
voltage of the lamp. |
|
observation: |
Insulators: rock, chalk,
wood, oxides(!)
Conductors: aluminum, copper, magnesium, all metals
Iron is a conductor, but not rust.
|
|
source: |
from Barke, H.-D. et al.: One Hundred
Chemistry-Experiments to Avoid Chalk and Talk; University of Muenster,
2004. |
