Physics Revision

• What are the 4 magnetic materials?

  Iron, Nickel, cobalt, some alloys of rare earth metals.
• Some uses for magnets?

  Compass
• Is aluminium magnetic?

  No
• How does a compass work?

  Earth has 2 poles- north and south. Lines of magnetic force connect these poles. the needle in a compass always arrange itself Along these lines.
• How to magnetise a piece of iron?

  Rub a magnet in the same direction a lot of times.
• How to demagnetise iron?

  Drop it, bang it against the table.
• Why is steel better than iron to be a magnet?

  Because steel doesn’t become demagnetised as easily as iron.
• How can an electro magnet be turned on and off?

  You disconnect it from electricity.
• how can you increase the strength of an electromagnet?

  Increase the current, increase the number of coils.
• State some uses for electromagnets.


  Bell, speaker
• State some types of energy.

  Heat,chemical,Nuclear,Magnetic.
• Why is energy important?

  we need it for our bodies to function properly.
• What’s the difference between heat and temperature?

  Heat is a form of energy, temperature is a measure Of that energy.
• What is thermal conduction?

  If something is a conductor, it means it lets heat through easily.
• What Is an insulator? 


  It’s a material which does not easily allow heat or electricity to pass through it.
• What is a conductor?

  A material that allows electric currents to pass through it.
• What is an independent variable?

  The variable that is changed
• What is a dependent variable?

  The variable that you measure.
• What is a control variable?

  the variable that is kept the same.
• What is a convection current?

  The way that heat is transferred throughout a fluid.
• Describe how global warming is caused.

  greenhouse gases in the atmosphere absorb energy, slowing or preventing the loss of heat to space. They act like a blanket, making the earth warmer, trapping the heat in.
• Remember

  
• What is an electromagnet?

  An electric current produces a magnetic field. This is called an electromagnet.
• The earths magnetic field.

  
• 1. Electric currents produce magnetic fields. 
  2. To increase the strength of an electromagnet you can increase the number of coils
  3. Another way to increase the strength is to increase the current, or use an iron core.
  4. The mini-magnets inside magnets are called domains.
  5. The earths magnetic field is useful because it allows people/animals to navigate.
• Heat can move by travelling as..?

  Invisible heat radiation.
• What colour is best at absorbing heat radiation?

  Black
• Which colour is best at emitting heat radiation?

  Black.
• In convection, particles that become warmer rise because they become less dense.
• What quantity is measured in Joules?

  Energy
• What is conduction?


  When particles in a solid vibrate and pass their energy to their neighbour.