Hello, I was wondering if anyone could tell me of an easily available (to a primary school teacher) solid material that conducts electricity, but noticeably poorly, so that it can be demonstrated and hopefully performed by 9 year olds. To be exact, I want a solid material that can be connected to a 3v battery and bulb using crocodile clip leads so that... a. the bulb will light up. b. the bulb will be dimmer or brighter depending on the length of this semi conducting material in the circuit. I had heard that lead and aluminium were poor conductors but when I experimented with a 1m aluminium rule and a strip of lead, there really was no noticeable change in bulb brightness at all. they may be poor conductors compared to copper, but I need something observable to a 9 year old's eyes. Any ideas? Thanks.