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Presentacion ppt publicar

  1. 1. .
  2. 2. INDEX 1.-What is Magnetism? 2.- What is a magnet? 3.- Types of magnets. 4.- the poles of a magnet.
  3. 3. 1.-What is Magnetism? Magnetism is the power of magnets to attract things. A magnet is an object that can attract metal objects made of iron, steel, nickel and some other materials. 2.-What is a magnet?
  4. 4. Magnets have been known for centuries. The Chinese and Greeks knew about the “magical” properties of magnets. The ancient Greeks used a stone called “magnetite.” They discovered that the stone always pointed in the same direction.
  5. 5. 3.- TYPES OF MAGNETS NATURAL MAGNETS ARTIFICIAL MAGNETS Are foundin nature. For example some rocks Are man-made. They are usually made of iron or steel. lodestone
  6. 6. Investigation What objects will attract to a magnet and which objects will not attract.
  7. 7. Object Material Prediction Result Was your answer correct? PENCIL PAPER CLIP COIN MARBLE SCISSORS KEYS PEN What will make a magnet move? XWOOD YES
  8. 8. Object Material Prediction Result Was your answer correct? PENCIL WOOD PAPER CLIP IRON COIN Steel covered by Copper. MARBLE GLASS SCISSORS IRON KEYS IRON PEN PLASTIC What will make a magnet move? X X
  9. 9. Paper clips attract... because they are made of iron.
  10. 10. Scissors attract. because they are made of iron.
  11. 11. Nuts and bolts attract. because they are made of iron.
  12. 12. The power of magnets.
  13. 13. 4.- The poles of a magnet. The poles are the parts of the magnet that Exert the strongest force on metal objects.
  14. 14. The blue end of a magnet is usually the south pole. The red end of a magnet is usually the north pole.
  15. 15. Investigation • What you will need :- Magnets (x2), a compass, some thread
  16. 16. 1.-Tie the thread around the middle of one of the magnets. 2.- Hold it up by the thread. 3.- Use the compass to see which is the north end of the magnet. (The north end of the magnet will point in the same direction as the north pointer in the compass). 4.- Repeat for the other magnet. Then answer the questions.
  17. 17. If you put two magnets together with different poles pointing towards one another, the magnets will pull towards each other. We say they attract each other. In this picture a north and a south pole are pulling towards each other (attracting each other).
  18. 18. If you try to put two magnets together with the same poles pointing towards one another, the magnets will push away from each other. We say they repel each other.
  19. 19. When two like poles are placed together they repel each other.
  20. 20. • So now we know that “like” poles repel each other… • and that “opposite” poles attract each other.
  21. 21. Magnets are in most electronic devices, in fact, anything that has a motor uses a magnet. They are used to slow down roller coasters and subways. More uses of magnets are found every day!
  22. 22. If you cut a magnet in half, you get 2 magnets!
  23. 23. A magnet has a ‘magnetic field’ distributed throughout the surrounding space Michael Faraday realized that ...
  24. 24. William Gilbert, an English physician, first proposed in 1600 that the Earth itself is a magnet, and he predicted that the Earth would be found to have magnetic poles.
  25. 25. The Earth is a magnet: Magnetic South Pole Magnetic North Pole It exerts magnetic forces and is surrounded by a magnetic field that is strongest near the North and South magnetic poles Geographic North Pole Geographic South Pole
  26. 26. We use the Earth’s magnetic field to find direction. The needle of a compass always points toward the magnetic south pole. We call this direction “North” (remember, opposites attract)
  27. 27. 1.- What is electricity? 2.- Types of electricity 2.1.-Static electricity 2.2.-Electrical current 3.- The movement of an electrical current. 4.- Elements of an electric circuit.
  28. 28. 9V + - Electricity is a form of energy. 1.- What is electricity? -+ Electricity give us light and heat. It also makes machines work. For example, Washing machines, computers and microwave ovens It is expressed in Volts (V)
  29. 29. 2.- Types of electricity Static electricity Electrical current
  30. 30. 2.1.-Static Electricity A stationary electrical charge that is built up on the surface of a material.
  31. 31. After being rubbed, a plastic ruler can attract paper scraps. The ruler has got static electricity. Is it magic?
  32. 32. Matter is made up of atoms. + + + – –– + – Proton (positive charge) neutron (neutral) electron (negative charge) atom nucleus No, it isn,t Explanation
  33. 33. When a ruler is rubbed with a piece of wool... – electrons are pulled from the wool to the ruler. The ruler has more electrons than usual. + + + + + – – – – – The ruler: – charged, The wool: +charged wool
  34. 34. HANDS-ON ACTIVITY • You will need: • Two balloons of two different colour per group. • Sticky tape. • A duster or wool cloth per group.
  35. 35. INVESTIGATION *Inflate the balloons (not too much) and tie a knot at the open end. Inflate both balloons to a similar size to make the test fair. Tie the string to the knots. *Rub one of the balloons with the wool cloth, but not the other. *Move your open hand near the balloon you didn’t rub, but without touching it. Then do the same with the balloon you rubbed .
  36. 36. BEFORE STARTING THE EXPERIMENT • 1.-QUESTION(WHAT DO WE WANT TO TEST)? • 2.-PROCEDURES: (HOW ARE WE GOING TO CONDUCT THE TEST.)? • 3.- PREDICTION( WHAT DO WE THINK IS GOING TO HAPPEN? • 4.-CONCLUSION: (WHAT ACTUALLY HAPPENED?)
  37. 37. USE A AN INVESTIGATION RECORD SHEET. *QUESTION: Will the two balloons behave the same way? *PROCEDURES: inflate two balloons. Rub one of the balloons with the wool cloth, but not the other. Move your open hand near the balloon. *PREDICTION: One of the balloons will move. *CONCLUSION: The balloon that was rubbed has got static electricity, that is why it moves.
  38. 38. 2.2.-Electrical Current Electricity is a flow of electrons around a circuit.
  39. 39. 9V + - 3.- The movement of an electrical current. e-1 -+ e-1 e-1 e-1 e-1 e-1 e-1 e-1 We classify objects according to whether they let in electric current pass through them in: CONDUCTORS INSULATORS.
  40. 40. Conductor Something that allows electrical energy to pass easily Metals (copper, silver) Some solutions.
  41. 41. Insulator Object that does not permit electricity to pass through it. wood glass plastic
  42. 42. Try some materials in a circuit to find out if they are CONDUCTORS OR INSULATORS. INVESTIGATION
  43. 43. Electrical charges can only flow through a closed circuit. When all the components are connected together, the circuit is closed. If the circuit is open, electrical current cannot flow. 4. Elements of electric circuits.
  44. 44. A circuit will only work if it is ___________. This means that it must make a complete __________ Otherwise the _____________ can’t flow. COMPLETE LOOP. ENERGY SUMMARY
  45. 45. conductor generator switch receptor
  46. 46. A which provides the electricity,for example, one or more batteries. like copper wires, which electricity flows through . , or loads, which transform electricity into another type of energy, for example a light, a buzzer or a motor. A to open or close the circuit The circuit also needs some components to work: generator Conductor Receptor switch (s) (s)
  47. 47. Component symbol Generator (battery) Conductor (wires) Switch open closed Receptor (light) Receptor (buzzer) Receptor (motor)
  48. 48. DRAWING A CIRCUIT
  49. 49. THE END

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