- How could the red light in the signal be made to go off and the green light come on?
- Why do you think the filament glows and produces light when electricity passes through it?
- Is there any writing on your light globe? Make a note of any writing for later reference in the discussion. You may have to use a hand lens.
- What do you think is inside the glass surrounding the filament?
- There is usually a glass blob on the two wires holding up the filament. This blob may have a colour. Check several other globes and see if there is a relationship between the colour of the glass blob and the numbers written on the side or top of the light globe.