Charge, Current and Voltage | GCSE Physics | Doodle Science

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Doodle Science teaches you high school physics in a less boring way in almost no time!

Script:
There are three things to understand when we talk about electricity: Charge, Current and Voltage.

All objects and materials have charge; it's created by the net of electrons or protons. If there are more electrons, the substance will be negatively charged and if there are more protons, it will be positively charged.

When a non-conductive substance such as plastic gets a charge by having electrons transferred to it, it creates a static electric charge. Such as when you rub a balloon on your head and it sticks or when you put your hand on a Van Der Graff.

Charge is measured in Coulombs and 1 coulomb is equal to the charge of approximately 6.241x1018 electrons.

Now the movement of this charge is called current and it's best to think of it as a river. Just as we measure the amount of water passing a point every second, current is the amount of coulombs passing a point every second. To measure it, we can put an ammeter in place to tell us how many coulombs are passing that point each second. But because physicists and engineers use this measurement so much, they decided to give is a name called an ampere or Amp.

Voltage or potential difference is a bit trickier to understand. The way I like to visualize it is by thinking of a lake that is completely still and therefore has no current. If we were to tilt the lake on its side, the water would rush from the higher gravitational potential to the lower. It's the same concept with Voltage, only instead of gravitational potential difference; we give it an electrical potential difference. We do this by using a battery for example, the battery gives one side of a wire more electric potential energy than the other side, so the current travels through the wire. The more potential difference we give it, the faster the current flows. Just as a steeper waterfall causes water to fall quicker.

But why do we call it potential? Because it is the potential to do work. The unit for the potential to do work is given in Joules per Coulomb and 1 of these is the same as 1 Volt because people decided to give it a name. Lets think of a 1.5V battery connected to a light bulb. What does the 1.5V mean? Well it means if 1 coulomb were to come out of one end of the battery, it could transfer 1.5J of light and heat before it entered the other side again.

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I have watched lots of videos on this topic and this one is definitely one of the better ones. I understand this concept better now, thank you.

magpiestudent

OMG, THANK YOU!!! I was struggling with what current, voltage and charge "meant" if that makes sense and you explained it like it was nothing!!!

Adonis-fztk

I'm doing A Levels, and I just cleared more doubts in two minutes than I've done in the past 6 months

tashreeqa_ek

OMG, thank you so much! I asked my teacher again and again about P.D but didn't get it, now I do a bit more. So P.D is the driving force behind current or is it the amount of potential a current has?

TheCriz

I saw of 100 of videos to clear my doubt.
But this was the best amoung them.It cleared my all the doubts.

CR-qswd

Good video - BUT need to change one thing - current does not flow "Faster" when there is a higher voltage. There will be more charge moving per second, but this has nothing to do with the speed of the electrons, only that there are more electrons moving. It is a common misconception with students that a higher current means that charge is flowing more quickly, which is incorrect.

Also worth pointing out the "double whammy" that there are more electrons moving AND each has a higher potential energy, which is useful later when talking about electrical power, I squared R, etc.

jeremyfisk

wow thanks. after so my effort to understand potential difference now I understand it.keep up the good work

fxcosta

Important point for anyone watching this, is that, current does not flow. Only "charges flow". That statement "current flowing" is the same as saying "flow of charge flow". It might seem pedantic to pick up on this use of the language, but it is one of the major causes of confusion with students.

kevinobrien

This video is the reason I didn't fail my physics exam

LucasJay

Just what I was looking for the other day. Managed to explain it without this video but it took me about an hour. :p

iamjimgroth

I don't suppose in these coronavirus times, there is a teacher out there who has already written a worksheet or teams form quiz to accompany this lovely video? I would love to hear from you!

vanessaowen

thank you for making a 3 second intro rather than The GCSE Guide's 30 second time wasting bullshit

PribPrib

thank you i understood that very well
amazing videos keep it up!!!

joebakir

Thanks a lot!!! I couldn't grasp this simple idea for two years from my igcse textbook, but now I can understand it just within minutes through this video!!

HohBrothers

Hi, excellent series of videos. Really useful. Would it be possible to put in the unit of voltage as J/C (unit / unit) rather than J/Q (unit / symbol)? Easier said than done I'm sure!!

simoneveritt