Electricity (SPRK) is a weird material with changing/unknown form. It is element number 16. It is in the Electronics section. It is bright yellow with a white glow.
A single spark of electricity has the life of 4. If a material "conducts electricity", the spark will create itself into those particles. Some particles conducts electricity only under some circumstances.
When spark is born, it's ctype is the particle the spark spreaded/was created to.
When spark dies, it turns itself into it's ctype and the material's life to 4 (however, it is more in Water, around 50). Spark cannot spread to material if it's life is more than zero, so this is to avoid spark spreading into material where it has left a moment ago. It also heats up itself before dying.
All electronics need electricity. It is also used in several types of triggers and switches. Since spark is used along with Silicon to (de)activate most Powered Materials, it is used in very many different devices that implement them.