Common swift that resemble a crescent or a boomerang. Their call is a loud scream in two different tone pitches, the higher of which issues from the female. They often form 'screaming parties' during summer evenings, when 10–20 swifts will gather in flight around their nesting area, calling out and being answered by nesting swifts. Larger "screaming parties" are formed at higher altitudes, especially late in the breeding season. The purpose of these parties is uncertain, but may include ascending to sleep on the wing, while still breeding adults tend to spend the night in the nest. Swifts may nest in former
Screaming jelly babies Screaming jelly babies "Screaming jelly babies" (en-UK), also known as "Growling gummy bears" (en-US/en-CA), is a classroom chemistry demonstration, variants of which are practised in schools around the world. It is often used at open evenings to demonstrate the more light-hearted side of secondary school science. The experiment shows the amount of energy there is in a piece of confectionery; jelly babies or gummy bears are often used for theatrics. Potassium chlorate, a strong oxidising agent, rapidly oxidises the sugar in the candy, causing it to burst into flames, producing a "screaming" sound as rapidly expanding gases are emitted from