Question: How does a lightbulb work?

Karen Reed answered on 20 Jun 2012:

Hi Meg – the old fasioned ones have a filiment in them – small thin wire – which when you pass electric through it, it heats up and glows giving off heat and light. THe newer energy efficent light blubs don’t have the filiment but instead are filled with inert gases which glow when electrecity is passed through them. So they don’t give out as much heat maing them more efficient