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Welcome to Mr. Taylor's 6th Grade Science Class! This page was created to keep both students and parents connected to the classroom. Science is now everywhere.

Monday, May 9, 2011

Unit B-Chapter 2-Lesson 1

How Does Matter Change State?

States of Matter

Matter exists in three states:
  • Solid
  • Liquid
  • Gas
A solid has a definite shape and definite volume
Example: Ice

A liquid has a definite volume, but no definite shape
Example: Water

A gas has no definite shape or volume.  It will occupy the volume of whatever container it is in.
Example:  Steam
  • In a solid, particles of matter are very close together and are held together by the attraction of the particles for one another.
  • When a solid, such as ice, is heated, its particles move faster and farther apart.  When the substance reaches its melting point, the solid changes to a liquid.
  • Eventually the particles gain enough energy to escape.  When the particles reach this point, the substance becomes a gas.
  • All three states of matter exist on earth.
Melting and Boiling
  • Although most substances normally exist on Earth in just one state, all materials can exist as solids, liquids, or gases.
On the surface of Venus, which is very hot, lead would be a liquid rather than a solid as it is on Earth.
  • The state of a substance depends on its temperature and the amount of attraction between its particles.
  • The temperature at which a substance changes from a solid to a liquid state is called its melting point. 
  • Melting occurs because particles gain heat.
  • When the particles in a liquid lose energy, they move more slowly. 
  • If the substance is cool enough, the particles slow down to the point where the liquid becomes a solid.
  • The temperature at which a liquid changes to a solid is called its freezing point.
  • In pure substances, melting and freezing occur at the same temperature.
Boiling and Evaporation

  • If a liquid is heated enough, all the particles in the liquid eventually will have enough energy to break free at the surface. (The liquid changes to gas)
  • The temperature at which this occurs is called the boiling point.
  • Different substance have different boiling points.
  • A substance can change from liquid to a gas through evaporation.
  • Evaporation is the change in state from a liquid to a gas at the surface of a liquid.
  • Evaporation can occur at any temperature because some of the particles at the surface always have sufficient energy to escape.
  • However, evaporation takes place more quickly in hotter liquids.
  • The change of state from a gas to a liquid is called condensation.

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