Kieselguhr (diatomaceous earth) is a type of silica formed in the earth from the skeletons of tiny organisms called diatoms. It is used in making fireproof cement, as a filtering medium, in explosives - Nitro glycerin is absorbed into Kieselguhr base to form Dynamite.

Firework flames are coloured due to chemicals added.

White : Potassium, Sulphur, Arsenic, Magnesium, Sb
Red : Strontium, Lithium
Green : Barium
Yellow : Sodium
Blue : Copper

Fuzzy logic is used in expert systems {e.g. - washing machine} to provide human like performance. The digital circuit consists of truth values carry probabilities such as true, very true etc. An expert system [Software/Hardware] works like a specialist consultant with the help of a knowledge base.

Infra red rays heats the objects on which it is directed without heating the surrounding air, thus wastage of energy is avoided.