SfC Home > Physical Science >

Reader questions and feedback on physical science. Also refer to physics, chemistry, astronomy, electricity, magnetism, electromagnet, light, sound, waves, forces, work, energy, friction, heat, thermodynamics, Ron Kurtus, School for Champions. Copyright © Restrictions

Answers to Readers' Questions on Physical Science:

Pressure and States of Matter

The following 6 comments and questions have been sent in. They are listed according to date.

List of first 10 items

• How much does water expand when it turns to steam?
• What state of matter is a cloud?
• How many times does water expand?
• Process of solid changing into gas
• Which water freezes first?
• Compressing air to an extreme

Next 10

How much does water expand when it turns to steam?

Question

August 27, 2009

How many times does water expand when it turns to steam? I say 1600 a friend of mine says 1728

Dean - Canada

18219

Answer

At atmospheric pressure, the expansion ratio between liquid water and steam is about 1:1700.

Of course, it depends on at what temperature you start also, but it is a good approximation.

Back to top

What state of matter is a cloud?

Question

May 5, 2007

In what state of matter is A CLOUD on the sky
Is it liquid or gas or a mixture whatever ?
thank you

denis - GREECE [HELLAS]

13709

Answer

A cloud is typically the gaseous state of water. But often tiny water droplets can form within a cloud, especially just before it starts to rain. In same cases, solid ice particles can form in a storm cloud, resulting in hail.

So, a cloud is usually a gas, but it can be a mixture under certain circumstances.

Back to top

How many times does water expand?

Question

October 18, 2006

How many times does water expand when it turns to steam?

Yamile - USA

12195

Answer

Water expands when heated. When it turns to steam, the steam itself expands.

Back to top

Process of solid changing into gas

Question

October 11, 2006

Dear school for champions I like your site and all but I asked what is the process of solid changing into gas and didnt get an answer leaving me to continue my search so if you please add this answer to your site I would really appreciate it. Also I noticed that you didnt mension the process of evaporation heat of fusion or any of those things so I think you should also add all the things like that.

- United States Virgin Islands

12139

Answer

Sorry taking so long to answer you. We've had too many email lately.

Our lesson on Changing States of Matter shows how changing a solid to a gas is called sublimation.
See: http://www.school-for-champions.com/science/matterstates_changing.htm

In Pressure and States of Matter, the chart shows that when the pressure and temperature is low, the material will skip the liquid phase and go directly from a solid to a liquid. For example, at very high altitudes (low air pressure) ice can go directly to become steam.

We may cover evaporation heat of fusion some time soon.

Back to top

Which water freezes first?

Question

August 17, 2006

when you put cold water and hot water in an ice tray, which one freezes faster?

joanie - USA

11716

Answer

Usually the cold water freezes faster, but there are exceptions. See our lesson on the Mpemba Effect at: http://www.school-for-champions.com/science/mpemba.htm

Back to top

Compressing air to an extreme

Question

April 3, 2006

1. Is it possible to compress air till it reaches 1000kg/m3.(ie. water density).?Please justify the answer.
2.What is the maximum pressure and temperature attained before there is a phase change into water?

KALYANAKUMAR - INDIA

10739

Answer

When air is compressed and liquefied, it can reach water density. For example, liquid Nitrogen has a density of 800kg/m^3.

Back to top

Next 10

Summary

Hopefully, this reader feedback has helped provide information about Science issues.

Resources

The following are some resources on this topic.

Websites

Science Resources

Books

Top-rated books on Physical Science

Miscellaneous

What do you think?

Do you have any questions, comments, or opinions on this subject? If so, send an email with your feedback. We will try to get back to you as soon as possible.

Feel free to establish a link from your website to pages in this site.

Where can you go from here?

School for Champions

Physical Science Topics

Answers to Readers' Questions