An example of an alternative conception in public discourse:
"It's always boiling tar, isn't it? It's never kind of lukewarm tar, like it always has to be bubbling, doesn't it, the tar? I feel like tar itself is enough, but for some reason people who use tar, it's always got to be a hundred degrees, you know, boiling point."
Comedian Toussaint Douglass was talking on an episode ('Causes of the British Civil Wars: Royalists versus Parliamentarians') of the BBC programme 'You're Dead to Me', commenting on an incident when Lady Eleanor Davies (1590-1652) was arrested and sent to Bedlam for pouring tar over the altar at Lichfield Cathedral.
This was intended to be humorous, not technically correct, but not everything boils at 100˚C. Different pure substances have different boiling points (and then varying according to air pressure), and mixtures do not strictly have definite boiling points. Pure water at atmospheric pressure boils at (or very close to) 100˚c, but most tars will only be bubbling at much higher temperatures.
Read about the nature of alternative conceptions
Read about some examples of science misconceptions
Read about historical scientific conceptions
Pouring a viscous material such as tar would be a very slow process (see the photograph below) if lukewarm, so it needs to be heated to be used effectively.
