Home > Physics > Solids, Liquids and Gases: Ice, Water and Steam

Solids, Liquids and Gases: Ice, Water and Steam

By: Suzanne Elvidge BSc (hons), MSc - Updated: 19 Feb 2018 |
Solid Liquid Gas Sublime Water Ice Steam

Water exists in three states – solid ice, liquid water and gaseous steam. Solids have a fixed shape and size. Liquids can change in shape, but have a fixed size. Gases can change shape and size.


Water freezes at 0 degrees Centigrade and becomes ice. On a cold, dry, clear morning, have a close look at the frost outside – these are crystals of ice.

Most solids are crystalline, where the molecules are tightly bound to each other, and are arranged in specific repeating patterns.

Half fill a clear plastic tub with water and mark the level of the water. Put it in the freezer overnight – does the ice take up more or less room than the water? Drop the ice into a bowl of water – does it float or sink?

In crystalline structures, the solid form of a substance usually takes up less space than the liquid form, because the molecules are tidily arranged. However, water and ice are unusual because ice takes up more room than water. This makes it less dense than water, so it floats (see ‘Floating and Sinking: Looking at Density’).


In liquids, the molecules are connected loosely to each other. This makes water flow and pour. The water molecules at the surface link more strongly to each other, creating what is called surface tension (see ‘Surface Tension: Keeping Bubbles Round and Insects Up’. This keeps water together in drops.

Run a tap slowly, or pour water from a jug into a bowl in a very thin stream and watch how the water molecules stay together and form drops.


At sea level, water forms steam it its boiling point, 100 degrees Centigrade. Steam is the gas form of water, and is also known as ‘water vapour’.

Put water in a pan and carefully heat it on the hob. Watch the bubbles form and the steam rise from the surface (be very careful – boiling water and steam can burn). Does the steam take up the same amount of space as the water?

In gases, the molecules are not connected to each other and can move around freely. The bubbles in boiling water are bubbles of steam that from at the bottom and rise to the surface. The air pressure in the room stops the bubbles escaping until they reach a certain size. At high altitudes, for example on top of mountains, water boils at a lower temperature than 100 degrees Centigrade because the air pressure is lower, and the bubbles of steam can escape more easily.

Burning Candles

Another example of solids, liquids and gases is a burning candle. Carefully light a candle and watch the surface of the candle and the flame. The flame melts the solid wax, creating a pool of liquid wax. This creeps up the wick inside the flame and becomes a gas, which then burns in the flame. The flame melts more wax and the cycle continues.


A few compounds go from solid to gas without becoming liquid in between. Solid carbon dioxide (dry ice) becomes carbon dioxide gas without becoming a liquid, as does iodine.

In some circumstances, snow and ice can sublime – sometimes, wet washing hung outside freezes solid and then dries without melting. This is called freeze-drying and is used in food preserving and for making instant foods and drinks.

You might also like...
Share Your Story, Join the Discussion or Seek Advice..
I want to ask that why steam and ice are similar? A..they can be compressed B..they can take the shape of any container C..they consists of the same type of particles D..The particles of both has the same amount of energy
Ada - 25-Apr-16 @ 12:48 PM
I was very confused and was not able to find my answer but these answers helped me a lot
dee - 10-Apr-15 @ 10:43 AM
showthe melting point of ice on the graph.
Talco - 30-Aug-12 @ 2:19 AM
Share Your Story, Join the Discussion or Seek Advice...
(never shown)
(never shown)
(never shown)
(never shown)
Enter word:
Latest Comments
  • The Science Guy
    Re: Why Oil and Water Don't Mix
    I’m a 10th grade student and I’m hoping S.O would write a paragraph on how to properly react Al or other metals with HCl or other…
    27 December 2019
  • Sarah
    Re: Making an Emulsion
    i hate airplane food they overheat EVERYTHING
    12 December 2019
  • Delly
    Re: Why Oil and Water Don't Mix
    I’m doing a project and it’s due in two days thanks for the info. I can finally rest after a long day of researching I’m in six…
    10 December 2019
  • Allycat
    Re: Why Oil and Water Don't Mix
    I am doing a fourth grade science project on this.My question is how or do a graph for this.?
    6 December 2019
  • Potent Pickle
    Re: Making an Emulsion
    My chin is very itchy... is it the lava laamp's greatness…
    21 November 2019
  • Timmy Timmy Timmy
    Re: Making an Emulsion
    bruh... what the heck is up with airline food
    21 November 2019
  • Mosey Cook
    Re: Make Yoghurt and Grow Yeast
    This article on natural yeast and good bacteria has been the best read I’ve read on the Internet
    1 November 2019
  • Tee
    Re: Vibrations: Seeing and Feeling Sound
    I have just witnessed a fork vibrating so fast on its own on the kitchen top. It made a sound while vibrating as if the…
    24 August 2019
  • simran panaich
    Re: Soap and Detergent Chemistry
    thnx!! It helped me a lot !!! THank YOu so much
    6 June 2019
  • Mar2
    Re: Why Oil and Water Don't Mix
    I am doing this as a demo for homogeneous mixture examples. It really helps, it is interesting, and thank you so much for it!!!
    5 June 2019