Energy Transfer and Efficiency | GCSE Physics | Doodle Science

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

Script:
Different types of energy can be transferred from one type to another. You can see that a car engine transfers chemical energy, which is stored in the fuel, into kinetic energy in the engine and wheels so it can get you from A to B. In a lamp the electrical input is converted into light energy. However not all the energy put in is turned into useful energy, some of it is turned into energy we don't need such as heat.

Sankey diagrams summarise all the energy transfers taking place in a process. The thicker the arrow, the greater the amount of energy involved. This Sankey diagram for an electric lamp shows that most of the electrical energy is transferred as heat rather than light. This means it's very inefficient. We can calculate efficiency using this simple formula, useful energy, in this case 10J divided by the total energy input, which is 100J, which gives us an efficiency of 0.1 or 10% if you times it by 100.

[FUBARFin]

Had to watch this in 0.5 speed to fully understand it >.>

[fury]

dude...in 1 minute I just learnt more than I would in a full hour of a physics lesson...
Why the heck do I have such a bad teacher XD

[sam_maundr]

quality clips. Deserves more recognition than it gets. Really useful stuff and these videos have helped me quite a bit.

[hydros]

antimatter is the best thing for energy efficiency, 100% energy transferred

[TheGoldSwordSquad]

physics gcse revision complete! oh wait watching one video isnt enough is it oh shit

[monkeyteaches]

went straight to the point i love it not like these other videos which keep making jokes

[iusewurst]

My guy innit posting the physics. Needed this for my A levels thanks bro.

[DietPepsi]

I agree with your maths, but I didn't really know how to explain it. I used to get confused with the 100% thing myself, as e.g. 1/2=0.5 and 1/2*100%=50%, I always got confused when thinking of it in terms of "per 100". These days I don't have to use such standard rules like part/total*100% anymore and I figured out how it really worked :). (I think this started when some "teacher"started jabbering about the % button on the calculator)

[jackgraffeo]

Nice short video explaining things well!

[АндрейДынин-лт]

Hello!
what the maximum speed of energy transfer?

[DietPepsi]

0.1=10%
10% basically means 10 per 100
0.1=10/100 -> rewriting gives -> 0.1*100=10 :)

[mrsmillward]

Your Sankey Diagram is not to scale - the total width of the output arrows should be the same as the input arrow :)

[masonlee]

How do u find out how much energy is useful and the total energy input I’m confused

[gendle]

How is "0.1*100" = 10%??
Isn't "0.1" already 10%?
I'm just a little confused.
I don't get that "*100" part of this.