Water good conductor?
You will need:
- 2 x small beakers
- ~ 100ml water
- ~ 1 teaspoon of salt
- ~ 1 teaspoon of sugar
- ~ 1 teaspoon of vinegar
- ~ 5 teaspoons of sodium bicarbonate ( if available)
- A pencil with exposed"lead" at both ends (eg sharpened at both ends)
- A range of small objects eg paper clip, rubber,elastic band, coin, plastic spoon? - to test for conductivity
In this two part investigation we are going to make a device to help us test the electrical conductivity of different solids and some liquids.
We started with an ordinary pocket torch and adapted it so that it no longer has an on/off button but has two wires coming out of instead. The wires have crocodile clips attached. If the crocodile clips are connected to each other or if both connected to a conductor the lamp will light.
We then used the device to test a range of different solid objects.
The tekkie bit..
An electric current is a flow of tiny charged particles called electrons. Electrons are part of what makes up all atoms and electrons are responsible for all the forces of attraction which hold particles together in elements, compounds and mixtures.
Metals have( mobile) electrons which can move from atom to atom . This is why metals will conduct an electric current when solid and when molten. The electrons in non-metals cannot move through the material so easily and so most non-metals cannot conduct an electric current.
Some liquids can conduct an electric current . Some of the liquids that conduct are the solutions which are formed when certain substances dissolve in water.These solutions conduct because the substance that dissolves releases charged particles into the solvent. The charged particles can move because they are in a liquid.