Give Now

A Moment of Science

What Does The Word “Sublimate” Mean?

The three states of water are solid, liquid, and gas. But, what happens when water "sublimates?"

ice cubes

Photo: Steven DePolo (Flickr)

Frozen water can freeze as well as sublimate.

You fill the ice tray up to the rim and put it in the freezer. The ice that results will be:

a.) at the rim
b.) over the rim
c.) under the rim.

Answer? It depends.

Water Expansion

It depends on how long you wait before checking on the ice again. My guess would be that most folks chose answer b: over the rim.

That is correct, if you checked on the ice trays after only a couple hours. That’s because water expands when it turns into ice, as you know if you ever put a soda bottle in the freezer and came back to find it exploded all over the fish sticks.

Ice Untouched

But if you were to leave the ice tray untouched for a couple of months, you might find the ice to be under the rim, or lower than the water was.

Wait…

Didn’t we just say water expands when it freezes?

Initially, yes. But frozen water can do something else as well: it can sublimate.

Sublimate

To sublimate is to go from one state to another without passing through the usual intermediary state.

By adding heat, ice can be melted into liquid water, which can be evaporated. That’s three states: solid, liquid, gas. But given enough time, ice can also turn into a gas without melting first!

When your ice cubes seem to have shrunk, it’s because they are sublimating: the frozen water is slowly evaporating off the cubes, without ever actually melting.

Stay Connected

What is RSS? RSS makes it possible to subscribe to a website's updates instead of visiting it by delivering new posts to your RSS reader automatically. Choose to receive some or all of the updates from A Moment of Science:

Support for Indiana Public Media Comes From

About A Moment of Science

Search A Moment of Science