{"id":4951,"date":"2016-09-22T19:38:16","date_gmt":"2016-09-22T18:38:16","guid":{"rendered":"http:\/\/mrsphysics.co.uk\/n5\/?p=191"},"modified":"2025-11-26T18:39:57","modified_gmt":"2025-11-26T18:39:57","slug":"voltage","status":"publish","type":"post","link":"https:\/\/mrsphysics.co.uk\/index.php\/2016\/09\/22\/voltage\/","title":{"rendered":"Voltage"},"content":{"rendered":"

\"gills-book\"<\/p>\n

Many teachers think that voltage is too difficult a concept for S1 students to understand.\u00a0By the time students get to AH we expect\u00a0them to be fully\u00a0knowledgeable about\u00a0voltage,\u00a0but we don’t\u00a0clearly explain it to them\u00a0as we go along. I\u00a0am as guilty as the next person of\u00a0doing this so…\u00a0. My new mission is to teach voltage as best and as fully\u00a0as I can to S1 and build on the concept each year so that by AH they will feel confident about this work.<\/p>\n

Having met Gill Arbuthnott at the Edinburgh International Book Festival (see post in Blog) I was really impressed with the way she tries to explain difficult concepts early on. She has given me permission to reproduce her page 16 on The Volt here.<\/p>\n

The Volt<\/p>\n

This was named after Alessandro Volta It is a unit of measurement in electricity. It tells us how much energy an electric charge has. You sometimes hear people saying things like, \u201cThe number of volts running through the circuit is…\u201d.\u009d This doesn\u2019t actually make sense! It\u2019s like saying, \u201cThe height running through the mountain is 1000 metres.\u201d Heights don\u2019t run, and neither do volts. There is no Usain Volt!<\/p>\n

What is a volt?<\/p>\n

So what is a volt? Imagine you are in a building with stairs and a lift. You carry a tennis ball up one floor in the lift, and let it roll back to ground level down the stairs. A battery is like the lift \u2013 it\u2019s a way of giving energy to something. In the building this is the ball \u2013 in electrical terms it\u2019s an electron.<\/p>\n

The ball rolling down the stairs is losing energy. In our circuit the equivalent is the electrons losing their energy to power a bulb. The voltage is equivalent to the height you take the ball up in the lift – more height is equivalent to greater voltage. And the distance the ball goes up in the lift must be the same as the distance it comes down by the stairs.<\/p><\/blockquote>\n

There are plenty of pictures in the book, but I didn’t think it was as easy to reproduce them. The book is full of more really interesting stuff, and even\u00a0material about coins\u00a0that Mr Chemistry opposite Mrs Physics didn’t know about (but then he’s far too young!)<\/p>\n

http:\/\/www.bloomsbury.com\/uk\/a-beginners-guide-to-electricity-and-magnetism-9781472915740\/<\/a><\/p>\n

Definition<\/strong>: <\/strong>Potential difference is the amount of work done to move an electric charge from one point to another.<\/strong><\/p>\n

or<\/strong><\/p>\n

Definition<\/strong>: <\/strong>The definition of voltage is the electromotive force or the electrical potential difference between two points in a circuit expressed in volts.<\/strong><\/p>\n

Voltage is a <\/strong>scalar quantity<\/strong><\/a>. The <\/strong>SI unit<\/strong><\/a> of voltage is the volt, such that 1 volt = 1 joule\/coulomb.<\/strong><\/p>\n

The easiest way to understand voltage is to use a water analogy. Using a hose as an example, think of voltage as the amount of pressure forcing water through a garden hose<\/em><\/strong>. The higher the pressure in the pipe the more water is forced through the pipe each second. <\/em>The greater the voltage, the greater the flow of electrical <\/em>current<\/em><\/a> (that is, the quantity of charge carriers that pass a fixed point per unit of time Q=It) through a conducting or semiconducting medium for a given resistance to the flow. <\/em><\/p>\n

One volt will drive one <\/em>coulomb<\/em><\/a> (6.24 \u00d7 10 18<\/sup> ) charge carriers, <\/em>electrons,<\/em><\/a> through a <\/em>resistance<\/em><\/a> of one <\/em>ohm<\/em><\/a> in one <\/em>second<\/em><\/a>.<\/em><\/p>\n

Voltage can be direct or alternating. A direct voltage maintains the same polarity<\/a> at all times. So charges always flow in one direction.<\/strong> In an alternating voltage, the polarity reverses direction periodically<\/strong>. The number of complete cycles per second is the frequency<\/a>, which is measured in hertz<\/a> (one cycle per second). An example of direct voltage is the potential difference between the terminals of a cell. Alternating voltage exists between the mains positive and negative.<\/p>\n

 <\/p>\n

\"Signature\"<\/p>\n

\n","protected":false},"excerpt":{"rendered":"

Many teachers think that voltage is too difficult a concept for S1 students to understand.\u00a0By the time students get to AH we expect\u00a0them to be fully\u00a0knowledgeable about\u00a0voltage,\u00a0but we don’t\u00a0clearly explain it to them\u00a0as we go along. I\u00a0am as guilty as the next person of\u00a0doing this so…\u00a0. My new mission is to teach voltage as best…<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1284],"tags":[],"ppma_author":[1267],"class_list":["post-4951","post","type-post","status-publish","format-standard","hentry","category-electricityn5","vs-blog blog-single wow fadeInUp"],"acf":[],"authors":[{"term_id":1267,"user_id":3,"is_guest":0,"slug":"n5","display_name":"Mrs Physics","avatar_url":"https:\/\/mrsphysics.co.uk\/wp-content\/uploads\/2025\/12\/OK-scaled.png","author_category":"","first_name":"Mrs","last_name":"Physics","user_url":"","job_title":"","description":""}],"_links":{"self":[{"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/4951","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/comments?post=4951"}],"version-history":[{"count":1,"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/4951\/revisions"}],"predecessor-version":[{"id":5283,"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/4951\/revisions\/5283"}],"wp:attachment":[{"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/media?parent=4951"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/categories?post=4951"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/tags?post=4951"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/mrsphysics.co.uk\/index.php\/wp-json\/wp\/v2\/ppma_author?post=4951"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}