My mum gave me a candle (unwanted present). When lit, the class holder that its in it changes colour. Might seem like a daft question but is it the candle wax that's changing colour or is it something in the glass holder that's changing colour?
Ta.
I think a strand of optical fibre alongside the wick senses the light of the flame and activates a set of colour LEDs at the candle's base. Once ignited, the candle then creates a display of continually shifting coloured light, from blues to reds... and almost every shade in between.
When it has burnt down Nails, if you dismantle the base you should find a battery and either LEDS or a colour changing LED in the base, it will either be a colour changing LED or a cluster of more than one colour, plus perhaps a tiny chip. Do tell us after it has expired.