Electric and gravitational fields
This list covers a topic that is usually taught in upper 6th physics lessons.
It is useful if students can recognise that fields are part of the model to explain forces acting at a distance and that they recognise how diagrams are used to represent the strength of these fields. Students will have some qualitative ideas about gravitational and electric fields from GCSE, when they meet the idea of gravity and electrostatics. However, they may not have met the idea of the field lines in relation to these two fields or the quantitative relationships.
It is possible to demonstrate electric fields using a variety of demonstrations, some of which are described in the items in this list.
The list also contains items which have problems that students can answer, tutorial videos that can be found on youtube and simulations that can be used to explore the quantitative relationships in electric and gravitational fields.
Learning opportunities included within this list cover:
- force fields, concept and definition
- gravitational force and inverse square field for point (or spherical) masses
- electric force and field for point (or spherical) charges in a vacuum
- electric and gravitational potential and changes in potential energy
- uniform electric field
- similarities and differences between electric and gravitational fields
Whilst this list provides a source of information and ideas for experimental work, it is important to note that recommendations can date very quickly. Do NOT follow suggestions which conflict with current advice from CLEAPSS or recent safety guides. eLibrary users are responsible for ensuring that any activity, including practical work, which they carry out is consistent with current regulations related to Health and Safety and that they carry an appropriate risk assessment. Further information is provided in our Health and Safety guidance.
Links and Resources
This resource links to four complete lessons, plans, experiments and resources on the topic of electric fields. Following the link to the lessons it is possible to use the lesson as described or gain ideas for practical activities and problems (with solutions) for use in lessons designed in school. The episodes in this topic are:
This resource is particularly useful for those composing schemes of work or those with less experience teaching A level physics. It is also useful for those looking for alternative ideas to incorporate into their lessons.
Using a Van de Graaff generator it is possible to produce very dramatic demonstrations that convey important aspects of topics related to electric fields and currents.
This video is aimed at teachers and gives practical advice on how to use a Van de Graaff generator. This piece of equipment can perform inconsistently in different conditions, but the video gives advice on how to combat these issues.
Further information on using a Van de Graaff generator can be found on the Practical Physics website. On the page are links to resources giving practical ideas on how to safely use the Van de Graaff generator to show concepts such as like charges repel, and that the force gets larger when the dome holds more charge. Under the sub-heading ‘related guidance’ there is a link to safety considerations when using the Van de Graaff generator, which will be useful reading for those less confident and/or experienced in using the apparatus.
Although the link is only to the ‘introduction’ section of the resource, there are links from there to the independent lessons. The resource is useful for those compiling a scheme of work, those with little experience of teaching A level physics or those experienced teachers looking for alternative activities. The teaching notes for the lessons contain suggested practical activities and explanations, as well as problems with worked solutions.
The linked page outlines the learning opportunities in this series of lessons.
The learning episodes in this series are:
This is an old resource, which is a PDF copy of an older book. Although the resource may not be found to be suitable to use as it is (it references BBC programs from the 1960's and Scientific American articles from the 1970's) there are many positive attributes for teachers compiling lessons and schemes of learning. For example on page 5 there is an extension activity about the determination of G. On page 11 there is an experiment on measuring the force between two charged particles that could be tried. The book also intergrates the topics of electric and gravitational fields in a way not many modern textbooks do, and makes links between physics concepts and calculus that may be of interest to students studying mathematics alongside their A level in physics. The resource also contains 'developmental questions', which are more thought provoking. Throughout the resource there is a large volume of questions to keep students thinking.