These questions are guidelines for your exposé. Feel free to use them in whatever order you want.

  Give the names of the metals used as electrodes.

  Which one of the electrodes is the positive one and which one is the negative one.

  What apparatus has been used to check that there is a potential difference between the electrodes ?

  Give the value of the potential difference.

  What LED means ?

  How do you recognise the negative terminal of the LED ?

  Is one lemon battery enough to light the LED ? If not what can you do to light the LED ?

  What is the minimum amount of batteries needed to light the LED ?

  How must you proceed to light a 12 V light bulb ?