Static Electricity
This resource package explores the use of practical activities to teach about electrostatics and includes some great advice on using a Van De Graaff generator with confidence.
Visit the practical work page to access all resources and lists focussing on practical work in secondary science: www.nationalstemcentre.org.uk/sciencepracticals
Demonstrating Physics: Electrostatics
A Van de Graaff generator is the classic way to demonstrate the production of static electricity and its effects. This reassuring film is specifically designed to dispel all your fears about using one and give you lots of great tips and ideas into the bargain. It even shows you how to use a hair dryer if the machine doesn’t work when you go to use it with a class – every teacher’s nightmare.
It’s a good idea to leave the Generator in front of a heater for a while after it comes out of storage, this will help to ensure there is no moisture on the belt. Having said that, if you know beforehand that it’s a damp day, it’s probably better to postpone the demonstration.
The film makes clear how to use a Van de Graaff without giving anyone an electric shock and for some students this will be really important. However, a few shocks can make for a great lesson and this film will reassure teachers that they can do this safely.
Van de Graaff Generator
This second film about the Van de Graaff generator is also very good. Not only does it explain clearly how it works, it also shows one of the very best Van de Graaff demonstrations – the flying cake cases. It’s really simple but very effective at illustrating the concept of electrical repulsion so start collecting those aluminium cake cases now. The cases that mince pies are sold in are ideal but if it’s not near Christmas you can use the internet to find a supplier.
Having seen the demonstration, and after picking up the cake cases from all over the floor, students should be able to explain what causes them to fly off.
Electric Sausage
If your school doesn’t have a Van de Graaff generator there are still lots of exciting demonstrations and experiments you can do on the topic of static electricity. This short film shows how to use a balloon to pick up paper (and explains how it happens). This is an experiment that the whole class can participate in. A similar experiment with a sausage is probably best as a teacher demonstration but definitely worth doing. A set of teacher notes is also available to download but it’s pretty well all covered in the film.
Other experiments that students can do with a charged balloon include:
Deflecting a stream of water. Turn on a tap until there is a thin but steady stream of water flowing. Now move the charged balloon towards the water (but don’t touch the water) and watch the water move.
Moving a drinks can. Empty aluminium drinks cans are light enough (like the paper scraps) to be moved by a charged balloon. Hold the balloon over a can that is lying on its side. As the balloon is slowly moved, the balloon will follow
Flying Tinsel
Physics is for life, not just for Christmas. This Christmas themed experiment would make a great practical for the last week of the autumn term but is also suitable for any time of the year. It follows on very well from the work with balloons detailed above but takes the ideas a bit further.
Electricity in the Home *suitable for home teaching*
This resource for the old Salters course provides a suite of practically based activities that will help to ensure that students understand the idea of an electric field and the forces they create. Not all of it is suitable for keystage three students but much of section 1 (What is Electricity?) leads on from the demonstrations listed above and will help to extend and develop understanding.
Instructions for practical work are given on the first two sides of student sheet 1.4 (numbered pages 12/13 in the booklet, pages 25+26 in the pdf document)
More able students could also match the problems caused by static with the solutions given on student sheet 1.2 (booklet p10, pdf page23)
You’ll find accompanying teacher notes on page 3 of the booklet (p16 of the pdf document) and there is an equipment list on page xi (page 12 of pdf document)
Electrostatics
The first three experiments with balloons in this plan from the Institute of Physics are simple to carry out and very clearly show repulsive and attractive forces. Thery would make a good whole class demonstration during which questioning from the teacher could assess how much the students already knew and challenge any misconceptions.
The second three experiments require the use of an EHT power supply. (EHT stands for extra high tension and tension just means voltage) Many teachers won’t have the experience or confidence to use one of these and in any case, these experiments are probably best left until students are older.
Be sure to read the very helpful teaching notes given towards the bottom of the page. Those teaching outside of their specialism will also find it worthwhile to read the related guidance on electrostatics. There’s a link right at the bottom of the page.