It's actually made or gas and dust that can extend hundreds of millions of kilometers away from the coma. most comets actually have two tails a plasma tell made of ionized gas and a dust tail made of small solid particles.
Using the same anchor points, he determined the freezing temperature for water to be 0 degree and the boiling temperature 100 degrees. The Celsius scale is known as a Universal System Unit. It is used throughout science and in most countries.
You can demonstrate evaporation by wetting a sponge and letting it sit out
