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Particle Theory

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Self Assessment

Requirements from ITT Primary Science National Curriculum

Self Assessment

1. Can you use particle theory to explain
   • why solids dissolve faster when
     • the liquid is hot ?
     • lumps are broken up?

     • the mixture is stirred?

   • ii. why clothes dry faster
     • on a hot day than a cold day?
     • when it is windy compared to when it is still?
       
       
2. Which of the following do you think are physical and which are chemical changes ?
• ice cream softening when removed from freezer
• bread cooking
• bleaching hair
• burning wood
• fat in bird cake going solid when cooled
  
  
3. How would you respond to a colleague who told you
• that when water boils it changes into oxygen and hydrogen as this is what it is made from
• dissolving is when one substance reacts with another to make one of them disappear
• in dissolving a solid disappears into the liquid
• melts when sugar is added to water and becomes liquid too
  
  
4. How would you answer the following questions from colleagues ?
• Do all solids melt?
• Does a solution always contain water?
• If something dissolves does it combine chemically with whatever it dissolves in?
• f a solution is saturated at room temperature will it still be saturated if you heat it up?
• If you smell something is it because there are molecules of it in the air?
• If orange juice is evaporated where does the colour go?
  
  
5. How would you try to explore with the following ideas given by children?
   • when a solid melted it gets lighter
   • when salt is mixed with water it disappears
     

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Requirements from ITT Primary Science National Curriculum

Particle theory and the conservation of mass:

• finely divided substances still contain many atoms and molecules;
• The movement of particles explains the properties of solids, liquids and changes such as dissolving, melting and evaporating;
• during chemical changes bonds joining atoms together are broken and new bonds are formed;
• mass is conserved in physical and chemical changes.
  

to support the teaching of KS1 and KS2 Programmes of Study, for example:

• to understand that gases are material even when they are invisible;
• to understand that matter is not lost during physical changes;
• to understand and explain the changes of the water cycle;
• to recognise that during chemical changes new materials are formed and matter does not just disappear.

Website maintainer: R. Jones Updated: November 13, 2000