Particle-theory - Notes and activities for grade 7

Particle-theory - Notes and activities for grade 7

• 1.
  Human particle demo. •Students can be used to demo different states – best done with slides 7-9 in background to aid understanding. • Solid – eight students arranged in a rectangular block (two rows of four). Each holds firmly with two hands to the student in front and cannot let go, while maintaining shoulder-to-shoulder contact with the adjacent student. Ask them to squeeze through a small gap between stools or benches – they can’t. What would happen if you held a lit Bunsen burner to their arms – they would let go and break apart. • Liquid – similar arrangement to above but holding on by one arm only and may break shoulder-to-shoulder contact for a second or two. Allows more movement, so they can get through a small gap. They can spread out a little, though this is limited unless you break their grips by burning them with an imaginary Bunsen  • Gas – eight students free to wander. Can “fill” the room but can also be pulled together to take up less space. If squeezed into a tiny cupboard, so they had no room to move, would they still be a gas?
• 2.
  Starter A. Is itpossible to go from one state to another and back again? Give examples. Starter B. Look carefully at the diagrams above. Can you explain why heating something can cause it to change state? Particle theory.
• 3.
  Particle theory. • Allmatter is made of tiny particles. • All particles are always moving. • Forces of attraction hold particles together. solid (strong forces) liquid (fairly strong) gas (weak)
• 4.
  Can you thinkof words for A-F? More heat energy = more movement. Melt Boil Freeze Condense less heat energy = less movement. A D B C F E
• 5.
  Which step are youon? Particle theory. 5-6: describe how particles move and are spaced in solids, liquids and gases. 6: use particle diagrams to explain the properties of solids, liquids and gases. 5: recall that all substances are made of particles.
• 6.
  Describe particles ina solid. Watch the video and listen out for key differences in particle behaviour between solids, liquids and gases. https://www.youtube.com/watch?v=bMbmQzV-Ezs Ask yourself: • Can the particles move (flow)? • Is anything holding the particles in place? • Can they be squashed together (compressed)? We will then model how these substances behave.
• 7.
  Describe particles ina solid. • The particles can vibrate in place but cannot flow. • They are held in place my many forces of attraction. • They cannot be compressed (squashed).
• 8.
  Describe particles ina liquid. • The particles can move around each other (flow). • They are still held together by forces of attraction. • They cannot be easily compressed (squashed). not fixed in place
• 9.
  Describe particles ina gas. • The particles can move freely in all directions. • There are few forces of attraction between particles. • They can be compressed as there are spaces between.
• 10.
  Which step are youon? Particle theory. 5-6: describe how particles move and are spaced in solids, liquids and gases. 6: use particle diagrams to explain the properties of solids, liquids and gases. 5: recall that all substances are made of particles.
• 11.
  Particle models explainproperties.
• 12.
  What state areyou in? I feel confident. Use particle diagrams to show why steam and water – but not ice – can leak out of an open bottle. I want lots of challenge. Carbon dioxide is unusual. When cooled, the gas does not form a liquid, it becomes solid! Show this with particle diagrams, include details of forces of attraction and particle movements. I want to cover the basics. Complete a cut & stick activity to get all the details on solids, liquids and gases.
• 13.
  Backup
• 14.
  Explaining changes ofstate. More heat energy = more movement. Melt Boil Freeze Condense less heat energy = less movement.