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Physics, Astronomy & Cosmology / Re: Energy balls versus circuits with batteries
« on: 04/02/2015 13:16:25 »
Annie
I know this Q&A is a year old, but I came onto the forum looking for the same explanation. After reading the helpful replies, I was still not confident of being able to explain it to someone else, so I asked Dr Simon Foster, a physicist, and this was his reply:
"When you touch the ball you don’t make a circuit which connects the battery to the light bulb (i.e. you become the wire) instead you complete the circuit on a tiny touch switch which then turns on the light. When you connect these 2 sides of the touch switch together (by lots of people holding hands) then the switch will be turned on and so the bulb lights up. Turning this switch on may only require a tiny DC current hence you won’t feel it. Essentially the switch is very sensitive hence only needs a tiny current to turn it on. If you were to try and complete the circuit in a simple circuit with just a battery and bulb, with people being the wire, then the current required to light up the bulb would be very high so you’d get a shock"
I needed to fully understand this as I am producing free online CPD courses for science teachers at primary level, (www.reachoutcpd.com) and we have filmed a group of children demonstrating a circuit with a similar gadget - I think they're great!
I know this Q&A is a year old, but I came onto the forum looking for the same explanation. After reading the helpful replies, I was still not confident of being able to explain it to someone else, so I asked Dr Simon Foster, a physicist, and this was his reply:
"When you touch the ball you don’t make a circuit which connects the battery to the light bulb (i.e. you become the wire) instead you complete the circuit on a tiny touch switch which then turns on the light. When you connect these 2 sides of the touch switch together (by lots of people holding hands) then the switch will be turned on and so the bulb lights up. Turning this switch on may only require a tiny DC current hence you won’t feel it. Essentially the switch is very sensitive hence only needs a tiny current to turn it on. If you were to try and complete the circuit in a simple circuit with just a battery and bulb, with people being the wire, then the current required to light up the bulb would be very high so you’d get a shock"
I needed to fully understand this as I am producing free online CPD courses for science teachers at primary level, (www.reachoutcpd.com) and we have filmed a group of children demonstrating a circuit with a similar gadget - I think they're great!