Current Events

  • Atmospheric CO2 Level Tops 400 ppm
    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm rep...Read more

    x

    Atmospheric CO2 Level Tops 400 ppm

    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm repeatedly. Daily levels of CO2 can vary due to weather, and there are seasonal trends as well. The level of atmospheric greenhouse gases continues to increase, now over 120 ppm since the Industrial Revolution began. For more on the Keeling Curve, see http://keelingcurve.ucsd.edu/. Find out more about greenhouse gases and warming.
  • Massive Tornado Outbreak on Tornado Alley
    The week of May 19 brings dozens of tornadoes to Tornado Alley in the states of Oklahoma, Kansas, Io...Read more

    x

    Massive Tornado Outbreak on Tornado Alley

    The week of May 19 brings dozens of tornadoes to Tornado Alley in the states of Oklahoma, Kansas, Iowa, Illinois and Missouri. On May 20th, a massive tornado struck Moore, Oklahoma, devastating communities - destroying over 100 homes and hitting two elementary schools and a hospital - with many casualties and deaths. Our thoughts are with our friends and colleagues suffering from these storms. For more on the May 20th storms, see the NOAA Storm Prediction Center Storm Report.
  • Kansas Legislator Proposes Bill to Outlaw Sustainability Education
    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of ...Read more

    x

    Kansas Legislator Proposes Bill to Outlaw Sustainability Education

    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of sustainability. Here is a link to the one-page bill: http://www.kslegislature.org/li/b2013_14/measures/documents/hb2366_00_0000.pdf. See report on Bloomberg News.
Water as a liquid, solid and gas.
Click on image for full size
L.Gardiner/Windows to the Universe

Changes of State: Solids, Liquids, and Gases

A snowman, glass of water and steam might look very different but they are made of the same stuff! Just like any substance, water can exist in three different forms, called states: solid, liquid and gas. The state will change when the substance is heated.

As a solid, a substance has a fixed volume and shape and is usually unable to flow, except in the case of glaciers. For instance, an ice cube or snowflake is the solid state of water.

When a solid is heated, it turns into a liquid. As a liquid, a substance has a fixed volume, but its shape changes to fill the shape of its container. For instance, a glass of water is the liquid state of water.

When a liquid is heated, it turns into a gas. As a gas, a substance does not have a fixed volume or shape. Gas expands to fill the shape and volume of its container. For instance, the steam that comes out of a hot teakettle, making the whistle sing, is water in the form of a gas.

Heat causes substances to change their state because, when heated, the molecules within the substance to move around faster. The faster the molecules bounce about, the weaker they are held together.

Last modified May 10, 2010 by Randy Russell.

Shop Windows to the Universe Science Store!

The Fall 2010 issue of The Earth Scientist, focuses on rocks and minerals, including articles on minerals and mining, the use of minerals in society, and rare earth minerals, and includes 3 posters!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Solid

Solid is one of the four common states of matter. The three others are gas, liquid, and plasma. There are also some other exotic states of matter that have been discovered in recent years. Unlike liquids...more

Molecules

Most things around us are made of groups of atoms bonded together into packages called molecules. The atoms in a molecule are held together because they share or exchange electrons. Molecules are made...more

Condensation

Condensation is the process by which water changes its state from a vapor or gas to a liquid. Condensation is responsible for the formation of clouds. Common examples of condensation are: dew forming on...more

Sleet and Freezing Rain

Sleet forms when a partially melted snowflake or raindrop turns back into ice as it is falling through the air. Sleet starts out in the clouds as a snowflake or a raindrop. If it starts out as a snowflake,...more

Kelvin Temperature Scale

The Kelvin scale is a temperature scale that is often used in astronomy and space science. You are probably more familiar with the Celsius (or Centigrade) scale, which is part of the metric system of measures,...more

Makemake: a Dwarf Planet

Makemake is a dwarf planet in our Solar System. Makemake was discovered in March 2005 by a team of astronomers led by Mike Brown. Makemake officially became a dwarf planet in July 2008. There were three...more

The Poles of Titan

Titan is the largest moon of Saturn. It is the second largest moon in the whole Solar System. Titan is the only moon with a thick atmosphere. Titan's poles are interesting places. Scientists have discovered...more

Shop Windows to the Universe

The Universe at Your Fingertips 2.0 DVD from the Astronomical Society of the Pacific is in our online store, filled with Earth and space science resources.

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF