{{:electricity:electricity-banner-790x50.jpg|Electricity Banner}} ====== Q3.1 How fast does the stuff move: ====== Discover how fast electrical current moves and what is moving. === CORE CONCEPTS: === Electrical current is a motion of something. How fast does this 'something' move? ++++ Q3.1 CLICK HERE TO SEE / HIDE STUDENT FLIP RESOURCES:| When a battery driven flashlight is turned on, the thin filament-wire gets hot and makes light because there is electric current in the metal. This current is a motion of something. How fast does this "something" move? Electrons move very slowly - like the minute hand on a clock {{youtube>jbi7gJTPSXk?640x360|How Fast is an Electron & Electricity}} **Video: How Fast is an Electron & Electricity** * IF UNABLE TO ACCESS YOUTUBE VIDEO (requires Flash) TRY:[[http://viewpure.com/jbi7gJTPSXk|How Fast is an Electron & Electricity]] * [[http://hyperphysics.phy-astr.gsu.edu/hbase/electric/miccur.html#c3|On-line calculator]] and [[http://amasci.com/miscon/speed.html|explanation]] - including speed for thin vs thick wires. ++++ ++++ Q3.1 CLICK HERE FOR A SCIENTIFIC EXPLANATION:| CALCULATING THE SPEED OF AN ELECTRIC CURRENT: Since nothing visibly moves when the charge-sea flows, we cannot measure the speed of its flow by eye. Instead we do it by making some assumptions and doing a calculation (maths not required for this part of the course). For an electric current in normal lamp cord connected to bright light bulb, the rate of flow works out to be around 100 millimetre per hour: Relatively, very slow! ---- ++++ ====== Q3.3 How is energy carried to the lamp: ====== Each electron carries energy to the lamp, deposits its energy in the hot filament, and then returns to the battery where it's re-filled with energy FALSE ++++ Q3.3 CLICK HERE TO SEE / HIDE STUDENT FLIP RESOURCES:| The correct answer is that the description is false. No additional video resources available for this question as the details are covered in other sections. ---- ++++ ++++ Q3.3 CLICK HERE FOR A SCIENTIFIC EXPLANATION:| FIXME - Coming soon The correct answer is that the description is false. No additional video resources available for this question as the details are covered in other sections. ++++ ====== Q3.5 When a battery runs down (goes flat): ====== When a battery runs down (goes flat), it's because all of its electrical charges have been lost or used up: FALSE ++++ Q3.5 CLICK HERE TO SEE / HIDE STUDENT FLIP RESOURCES:| No video resource available yet - please read the SCIENTIFIC EXPLANATION below. ---- ++++ ++++ Q3.5 CLICK HERE FOR A SCIENTIFIC EXPLANATION:| CREATION AND LOSS OF ELECTRICITY: * Batteries don't make any electricity * Generators don't make any electricity * Solar cells don't make any electricity * Fuel cells don't make any electricity * Rubbing fur on plastic doesn't make any electricity * VandeGraaff machines don't make any electricity If all of the above devices don't make electricity, then what DO they do? Simple. All of them are electricity pumps. When a battery runs down, it's because its chemical fuel is exhausted, not because any charges have been lost. (A battery is just a Fuel Cell that keeps its chemical fuel on board). Batteries are charge pumps. They just force the charges that are already inside the wires to flow along. When you 'recharge' a battery, you are pumping charges through it backwards, which reverses the chemical reactions and converts the waste products back again into chemical fuel. If the above conflicts with some teaching resource you may find, remember that most K-12 textbooks define electricity very differently than scientists do (The core teaching resources used for this quiz explicitly nominate the use of the 'scientific definitions' to be taught in Australian schools). In scientific terms, 'electricity' means 'charge'. CAN WE CREATE ELECTRICITY: Electricity is a fundamental property of matter, so in order to create electricity, we have to create matter. The positive and negative charges of electricity are permanently attached to the electrons and protons in atoms. To make electricity we'd have to create protons or create electrons! There is no easy way to make electric charge out of thin air. It's not impossible though. If you have a gigantic particle accelerator at a physics laboratory then you can create new charged particles. The same thing happens naturally in radioactive materials and when cosmic rays from space strike atoms down here on earth. But other than that, and no matter what advertisements you may see to suggest the contrary, it's not possible to make any electricity. If a textbook says that electric generators make electricity, that textbook is using the word 'electricity' in an unscientific way. ---- ++++