Welcome to the Term 4 2024 issue of SCIOS – Secondary.
We welcome and encourage articles from teachers and students and so it is with pleasure that in this issue of SCIOS we publish an article from Year 8 students in Willetton Senior High School’s Science Club on their development of a class demonstration of the photelectric effect
While a short issue we hope in the busy-ness of end of year activities you will find time to read about the efforts of this group of students and that it may inspire teachers and other students to share their experiences of learning science in our schools
Allan Knight (SCIOS - Secondary Editor)
DEMONSTRATING THE PHOTOELECTRIC EFFECT USING COMMON CLASSROOM MATERIALS
Nanziba Anjum, Bithum Bodhinayake, Michael Konig, Lucas Lindsay, Archer Nowrojee, Yashitha Tippanur Venkata, and Leon Harris*.
*To whom correspondence should be addressed, leon harris@education wa edu au
AUTHOR BIOGRAPHIES
Leon Harris is a teacher at Willetton Senior High School The authors are a group of Year 8 students who meet one hour a week after school to participate in Science Club, where they have used the subject of electrostatics to look at physics, biology, and weather They have been looking at reforming and improving a number of science activities which they hope to feed into their classes
This project aims to demonstrate the photoelectric effect using common laboratory classroom items
The photoelectric effect is the emission of electrons when exposed to electromagnetic radiation of sufficient energy and occurs when high energy light bombards a metal surface knocking electrons from the surface
The photoelectric effect was first explained by Albert Einstein in 1905, for which he was awarded the Nobel Prize in Physics
It is difficult to demonstrate this effect in a classroom environment because of the large amount of energy required to remove an electron from the surface of a metal This energy is called the work function of a metal It is difficult to obtain a source of light with enough energy to produce observable results During Willetton Science Club we initially attempted to demonstrate the photoelectric effect attempting to use a small, handheld Van de Graaff generator It proved ineffective as it was charging the device positively when the experiment required a negative charge
We attempted to use solar energy; however, it had no noticeable impact upon the device We then also attempted to use an ultraviolet light emitting diode, and a UV light however, the wavelengths were not short enough and so did not demonstrate the photoelectric effect
Then our teacher suggested that we use burning magnesium as it emits high energy ultraviolet light The modification also had the advantage of being an indoor experiment that was a more controlled setting instead of being in the open air.
The experiment was successful with the burning magnesium emitting a high enough level of energy in the form of light to surpass the aluminium can’s work function and produce promising results that demonstrated the photoelectric effect
We wish to share the methodology and results of our experiment including the extra steps that we needed to take to make this demonstration successful
Materials:
We used the following, items to conduct this experiment:
sandpaper
aluminium can
Styrofoam cup
magnesium strips
metal paperclip
metal tinsel
balloon
tape
Bunsen burner
matches
orceps
bench mat
Method:
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Sand an aluminium can until all paint is removed and the bare metal shines (Sand the can before emptying so it is not dented)
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Tape 6 strands of 10 cm metal tinsel around an unfolded metal paper clip
Attach the metal tinsel to the sanded soft drink can and place on top of a Styrofoam cup
Charge up the balloon with static electricity by rubbing on hair, then touch it to the metal tinsel (not the can) so that they separate from each other
Light and set the Bunsen burner to a blue/ intense flame
Using forceps, take one magnesium strip and hold it near the hottest part of the flame until it has ignited Do not look at the burning magnesium strip
Bring the lit magnesium strip near the sanded can and record your observations
Before repeating the experiment, sand the aluminium can again to ensure satisfactory results
Watch the strips of tinsel, NOT the burning magnesium!
Diagram of Photoelectric Effect Experiment:
Discussion
This experiment demonstrates the photoelectric effect on the freshly sanded aluminium can When photons of light with enough energy strike the aluminium, they cause electrons to be knocked off the metal onto the surrounding particles of air This causes the aluminium can to lose its negative charge and become positively charged when compared with the strips of tinsel
The negative charge caused the tinsel strips to repel each other, when the electrons are hit off the sanded side of the aluminium can by the particles of light, the electrons move from the tinsel to the can to equalize the charge across the can This then causes the tinsel strips to collapse/fall as they are no longer repelled by each other
It required many attempts to obtain a satisfactory result, and the principal difficulties were: The can must be charged with a negative device, and so most school Van de Graaff generators will not work as the dome is positive 1
Care is required with the polystyrene cup as it may conduct charge Our science teacher theorises that the older the polystyrene becomes, the more likely it is to conduct charge and therefore interfere with the experiment (This is due to oxidising of the polystyrene as it turns yellow At high voltages, even high resistances can conduct small currents and discharge the can – LH) 2
It is necessary to sand the can each time you use it, as the aluminium quickly develops an oxide layer 3
It was found that LED lights and UV fluorescent lights did not emit light with sufficient energy and burning magnesium was satisfactory 4
We hope that our experiences will enable other teachers to demonstrate this phenomenon
References
2.
1. Anon, Work functions for photoelectric effect http://hyperphysics phyastr gsu edu/hbase/Tables/photoelec html accessed 21st August 2024
Beehler, AJ 2010 – Demonstrating the photoelectric effect using household items The Physics Teacher 48:348-349
Friday, 8 November 2024 WA Maritime Museum Victoria Quay Road, Fremantle, WA 6160
Website: https://scienceiq net
Developed by the Science Teachers’ Association of Western Australia (STAWA), ScienceIQ is proudly supported by the Royal Society of Western Australia (RSWA)
ScienceIQ is an online science quiz for school teams of four students
Teams have one hour to complete up to 12 science questions and problems in two separate rounds of competition Each round is a week apart and teachers choose the days and time to do each quiz To win, students will need to finish in the shortest time with the most questions correct.
Participation certificates, first, second and third place prizes, and other great stuff.
TERM 4
Year 8 and a joint Years 5 & 6 competition
Rd 1 week of 4 Nov
Rd 2 week of 11 Nov
Register via the STAWA website.
Log-in details and instructions to access the practice quiz will be sent to the teachers of the registered schools prior to the competition date
The 72nd Conference of the Australian Science Teachers’ Association, CONASTA 72, will be staged in Perth from 7-10 July 2025, hosted by STAWA This conference is the premier professional learning experience for teachers of science, in primary and secondary schools, across Australia
CONASTA has a strong reputation for offering high quality, stimulating professional learning experiences and we wish to build upon this reputation by showcasing WA Science and industry.
MEMBERSHIP INFORMATION
Here are just some of the benefits and opportunities for STAWA Members Please check our website for details, and to find out what else STAWA does - PLUS what STAWA can offer you! (www stawa net)
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A range of resources for both Primary and Secondary teachers is available on the website Look for the Resources Tab There are resources available to members and non-members. Members can also share resources through the STAWA website. You can download resources directly from the website or request to upload resources by contacting the Office (admin@stawa.net).
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Catalist is an email communications list which reaches over 800 Science Educators and is used to share information, ask questions, and discuss current issues To subscribe to Catalist, look under the Teachers Tab on the website
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Full fee-paying members enjoy the benefits of affiliated membership to the national association This includes access to ASTA’s online journal, Teaching Science, and the Chrysalis online learning community
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Jeff Cahill Early Career Teacher Award
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HOW TO CONTRIBUTE?
CAN YOU CONTRIBUTE TO SCIOS?
YES, of course you can Contributions from teachers, laboratory technicians, students, academics and industry are all welcome
We are keen to increase the number and variety of types of articles published in the SCIOS So, if the answer is YES to any of the following questions, please consider submitting an article to the editor
Have you recently conducted an experiment (investigation or hands-on activity) that worked well?
Is there a great demonstration that always gets your students’ attention?
Have you tried a new teaching technique that really engaged your students?
Do you have some helpful hints for new (and not-so-new) teachers?
Are there some safety hints and tips that you would like to pass on?
Are you using some new technology that has improved the effectiveness of your students’ learning?
Are your students involved in a science project outside of school?
Have you recently attended a useful/interesting professional development activity?
Email your contributions to admin@stawa net
GUIDELINES FOR AUTHORS
These notes are a brief guide to contributors who should also refer to recent issues of the journal for guidance with style
Longer articles - should not normally exceed 3000 words plus figures, tables and any references Please use headings and sub-headings to give your article structure
Shorter articles - We also welcome shorter articles of approximately 500-1000 words plus figures, tables and any references Again, use of headings and subheadings may assist to give your article structure
Send the following to the editor:
1
Please send your document as a word file with photographs and other images embedded where you need them to be
2
3.
Photographs and other images (e g diagrams) should be sent as separate files
Photographs often increase the clarity and interest level of your work Send your photographs as tiff or highest quality jpeg files with a resolution of at least 300 dot per inch (dpi) Note to teachers: a signed parent permission slip must be obtained for any photographs of students to be included in SCIOS.
4.
Copyright for any part of your contribution that is copyright of a third party needs to be obtained in writing (email acceptable)
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