Eli5 What cools faster?



What cools faster? A block of ice or chunks of ice? In a cup of water for example.

In: Chemistry

Chunks of ice cool faster, because they have more surface area in contact with the fluid (air and water) inside the cup. Gently stirring the fluid will also speed the process, allowing warmer parts of the fluid to more rapidly come in contact with the ice than through thermal circulation.

Whichever has the highest surface area, which in general will be the chunks. High surface area means more contact between the cold stuff and the not-cold stuff, which means faster absorption of heat.

Chunks of ice will cool faster : it’s all about the surface area

Heat can transfer in either conduction or conviction (also radiation but never mind that for now)

In these methods, heat travels from one place to another by physical contact. Basically, the atoms that make up all matter, collide with each other, atoms that move faster or have more energy are “hotter” and when they collide with atoms that move slower, they transfer some of their heat. When you put ice in liquid water, the atoms of the water and the atoms of the ice collide with each other, the water which is hotter has faster atoms, and when they collide with the slower atoms of the colder ice are slowed down and that water is cooled while the ice is heated (until it turns to liquid). So the more surface area, the more atoms of water can touch atoms of ice. When you break the ice into chunks, you make more surface area between the ice and the water.