Science teacher told that switching sockets off saves electricity

[Zontiki]

There are switches on the electric sockets.
Science teacher in DD's school said that if it is not switched off and even if nothing is plugged into the socket, it still consumes electricity.
Now the girls in the school walk through corridors and switch empty sockets off.
What do you think about it?

yes, that's because an appliance is plugged in! if no appliance, the circuit isn't complete, so no current through it.
Clearly this isn't a specialist science teacher, but what strikes me is that this is very basic common sense science, one wonders if they even have a GCSE themselves.
As PPs have said, do take it up with the school. We had a situation where DD was basically not being taught anything - I won't give details as outing- but HoD took it v seriously and things changed.

Oddboots transformers do- they are warm to the touch, even when not in use- but charger plugs don't- they are cold when no current is flowing through them.

I suspect that the pupil listening to the teacher misunderstood what was meant.

Normally the concept is that if nothing is plugged into that socket then no current can flow but being a real smartarse as its an AC current the metalwork in the plug,after the switch that is, will form a capacitor of very low value, picofards, ie sq'rt of sod all! but as its AC albeit a very low frequency a current would flow!

I suppose i could nip into the works and put one on a LCR measurment set and then work it out but can't be arsed as it'd be so low i wouldnt bother anyone about it;!

Well according to the Scottish governments fire safety department switching off and unplugging at the wall does save electricity and money (see below).

No electricity will be used if nothing is plugged in.

Shit I read the OP really badly. I guess I just filtered out the bit about 'empty sockets'; I thought we were talking things that were plugged in but not in use.

Well that KS3 curriculum helpfully provided by @LolaSmiles clearly shows that pupils these days are expected to spend their science lessons coming up with ideas, evaluating their own results and questioning everything rather than learning actual facts.

Oh dear. No wonder so many kids leave school knowing fuck all.

That isn’t the entirety of the science curriculum though. It’s the preamble to the science curriculum.

rafals
It says that:
The principal focus of science teaching in key stage 3 is to develop a deeper understanding of a range of scientific ideas in the subject disciplines of biology, chemistry and physics. Pupils should begin to see the connections between these subject areas and become aware of some of the big ideas underpinning scientific knowledge and understanding
The bullet points underneath clarify what's commented on in the curriculum statement in terms of skills and topics.

www.gov.uk/government/publications/national-curriculum-in-england-science-programmes-of-study/national-curriculum-in-england-science-programmes-of-study#key-stage-3

But as others have said the majority of secondary schools don't have to follow it.

The KS3 curriculum documents for most subjects are a broad overview, and schools don't even have to follow it. The English one for example, contains list of language knowledge but it's non-staturory, so it's statutory knowledge at year 3-6, but then is entirely optional at y7-9.

National curriculum documents at secondary are very often not really worth the paper they're written on as school will plan backwards from GCSE.

gostiwooz
It does say that they have to have:
The principal focus of science teaching in key stage 3 is to develop a deeper understanding of a range of scientific ideas in the subject disciplines of biology, chemistry and physics

But a lot comes down to the fact that most schools can do what they like.
If they're an academy school then you could get a school like mine that has a really strong curriculum, lots of content etc, or you could get a social issues approach to science like the OP's school.

Well according to the Scottish governments fire safety department switching off and unplugging at the wall does save electricity and money (see below).

Reading the screen shot, it is referring to the appliances themselves, not the plug sockets. Yes, even on standby etc, some appliances still consume electricity so might be an idea to unplug when not in use.

I understand that it’s not worth the paper it’s written on because most schools don’t have to follow it but IMO your post was misleading.

I don’t think that poster is the only person that would be led to believe that what you posted was the whole of the ks3 science curriculum given the two sentences preceding it.

It wasn't intended to be misleading, which is why I posted the link and clarified with the poster who said they don't know anything that it does talk about knowledge in the 3 areas

But when you read through the bullet points, it doesn't really add anything to the overview, just a list of topics to flesh out the "knowledge of key ideas".

Just checked with my DH who tends to know about these things he says

• if there is an LED light showing on/off then it will consume
• if there is also a USB socket then may consume
• otherwise if nothing plugged in then it won't consume
• if there is something plugged in then it may consume even if not on
• some things consume more off than on as a red LED needs more power than a green one

Actually it can save electricity. If you are on AC (which we all are) the wires leading to the socket can act like a capacitor and consume a small amount of electricity even though there is no connection. There are videos on YouTube of the effect that this produces (and one of a light bulb in an incomplete circuit). If the wires are set up in a different way the electromagnetic fields won’t interact in a way to have this effect but often they do.

However, the energy consumption is negligible

@Parsimon, if you turn off or on the switch on the socket with no appliance connected to it, the wires leading to the socket will still be exactly the same and the effect described by you will not change, right? So I don't understand your point.

Actually @Zontiki you are completely correct and my argument only holds if the switch is elsewhere in the circuit where it would have an influence on the capacitive effect.

Actually it can save electricity. If you are on AC

AC is rather lossy to transmit over long distances so sometimes very high voltage DC is used, they convert back to AC at the other end!..