*Electrical circuits - the basics* *Elektriese stroombane - die basiese*

A simple way of how an electrical circuit (direct current) work.

Click here for the English version.

'n Eenvoudige manier oor hoe 'n elektriese stroombaan (gelykstroom) werk.

Klik hier vir die Afrikaanse weergawe.

English version

It is very important that learners have a good comprehension of the basic concepts of electrical circuits and can effectively apply the cognitive processes about the interaction between current, potential difference, resistance, energy and power. 

This piece is an attempt to make these challenges easier. It is a refined and adapted form of a method that I was introduced to in my first year as a teacher by my former subject advisor, Mr. Louis Maas. I would like to give credit to him for the initiative, as he has played a huge mentoring role in my life 40 years ago.

What I present here, I have used with great success in physical science; for both learners and later also during teacher training.

You are welcome to distribute this piece. I just request that it not be modified and that the copyright mark be distributed along with the piece. I hope this is of great use to you. Click here for access to the pdf document and to download it.

©Henry Welman (HFDW)

Afrikaanse weergawe

Dit is baie belangrik dat leerders die basiese begrippe van elektriese stroombane goed begryp en die kognitiewe prosesse van die interaksie tussen stroom, potensiaalverskil, weerstand, energie en drywing effektief kan toepas. 

Hierdie stuk is 'n poging om hierdie uitdagings makliker te maak. Dit is 'n verfynde en aangepaste vorm van 'n metode wat ek in my eerste jaar as onderwyser mee kennis gemaak het by my eertydse vakadviseur, meneer Louis Maas. Ek gee graag die eer aan hom vir die inisiatief, aangesien hy 40 jaar gelede 'n groot mentorsrol in my lewe gespeel het. 

Wat ek hier aanbied, het ek met groot sukses in fisiese wetenskap gebruik; vir beide leerders en later ook tydens onderwysersopleiding.

Jy is welkom om hierdie stuk te versprei. Ek versoek net dat dit nie aangepas word nie en dat die kopieregmerk saam met die stuk versprei word. Ek hoop dit is van groot nut vir jou. Klik hier vir toegang tot die pdf-dokument en om dit af te laai.

©Henry Welman (HFDW)

William Smith has died

Dr William Smith decorated by President Cyril Ramaphosa in April 2019.
Photo credit: Netwerk24.com

Today, Wednesday 21 August 2024, Netwerk24 and News24 reported that the iconic South African teacher, Dr William Smith, died peacefully in Australia after a short battle with stage four cancer.

Dr Smith started his ground-breaking physical sciences and mathematics classes on SABC TV in the 1990s. He was an amazing teacher with a practical and hands-on approach to excellent explanations. He helped millions of learners to understand the subject content better, and he helped thousands of teachers to improve their own explanations of the subject content.

Apart from his amazing career and service to teachers and learners of South Africa, something of special interest to me is that Dr Smith appeared as a boy in a picture that was taken when the second coelacanth was brought to South Africa.

William Smith as a boy on the far right.
Photo credit: saafmuseum.org.za

This amazing story can be read here and here. We thank the websites and authors for documenting this interesting history.

My sincere condolences to Dr Smith's family. What a great honour it was to have experienced this man!

Very interesting interview with Neil Armstrong

A few days ago, I posted something about the first moon landing in 1969.

Since then I discovered an amazing interview that was held with Neil Armstrong.

It was done by Alex Malley, the CEO of Certified Practicing Accountants, an organisation in Australia. Mr Malley did an outstanding job and showed so much respect, grace, and good humour.

Do yourself a favour and view it here. There is so much to learn for everybody.

The description of the video is as follows:

In this interview, the first man to walk on the moon gives a personal commentary on Apollo 11’s historic lunar landing along with his thoughts on leadership and taking risks to innovate for the future.

Neil Armstrong is a household name, yet, in contrast to his crew-mate Buzz Aldrin, he has studiously stayed out of the spotlight in the decades since he walked on the Moon. He frequently passed on interview and advertising requests, all the while beating back unwelcome advances on his legacy.

So it was a coup of sorts for Certified Practicing Accountants organization of Australia to score an extended interview with Armstrong, a connection that seems about as natural as a two-headed kangaroo. (CEO Alex Malley had developed the relationship, sharing his concerns about long-term strategic planning both in business and politics with Armstrong. The interview was a part of CPA Australia’s 125th anniversary celebration.)

Armstrong shows flashes of the rationality and equanimity that made him an ideal astronaut candidate in the first place. He confesses that he gave Apollo 11 a 90% chance of returning home safely, but just a 50% chance of landing on the Moon successfully. He expresses a sense of fate about his dangerous work as a test pilot and astronaut, refusing to worry about future tasks because he figured something would go wrong first and he’d be otherwise engaged firing the ejection seat or scrambling to repair a valve. Of his time on the Moon’s surface: “we weren’t there to meditate, we were there to get things done.”

First Moon Landing 55 years ago

Today, 20 July, we commemorate the first Moon Landing.

The Union of Soviet Socialist Republics (USSR), commonly known as the Soviet Union, was the first country to put a man in space. It happened on 12 April 1961 when Yuri Gagarin became the first man in space. Click here and also here to read more about him.

Click here for a short voice recording of his impressions. According to the Scientific American, Gagarin’s first spoken words were: “The Earth is blue, how wonderful.” Later: “The Earth was moving to the left, then upwards, then to the right, and downwards … I could see the horizon, the stars, the Sky,” Gagarin said. “I could see the very beautiful horizon, I could see the curvature of the Earth.”

On the 25 May 1961, the president of the United States of America, John F Kennedy, set a goal to land a man on the moon and return him safely back to Earth. Click here to listen to this sound clip.

Through science and mathematics, engineering, and lots of motivation and hard work by many men and women, the rocket carrying the first three Americans to the moon was launched on 16 July 1969. Click here for the sound clip.

On 20 July 1969, Neil Armstrong set foot on the moon, followed by Edwin (Buzz) Aldrin. Click here to listen to Armstrong's famous words.

What a remarkable achievement 55 years ago!

Retirement and another website

Dear Readers

I have recently retired from the service of the Free State Department of Education. It was a pleasure to maintain this website for you for the past 17 years. 

I started this website in 2006 (in those days on another platform) to create an e-platform with the primary goal to support the physical science teachers, and later the technical science teachers, of the Free State. We did not have an official e-platform for that purpose in those days, and I decided to do my own thing. From April 2014, I used Google services to continue the original website, and it eventually grew to a platform with quite an audience, including international visitors. See the picture at the bottom of this post.

To all of you, I want to extend my gratitude for visiting my website, and for the numerous messages of appreciation that I received from so many of you. At the time of posting this message, the website was visited 871 158 times. Rest assured that it was a pleasure to put each post on the website.

To continue serving you, I started to put plans in action in August of 2022 for the continuation of this service. I asked one of the subject advisers in my team, Mr Nkosi Nambane, to create a platform for that purpose. Official documents from the National and Free State Departments of Basic Education are now available on Mr Nambane's website, plus other material that you normally find helpful. 

The address of Mr Nambane's website is https://www.nambaneacademy.com. Put in an effort to become familiar with the new layout, and also follow his YouTube channel with online lessons.

"hwscience" will not stop, but in time I will probably change the focus a bit. Hence, I will still post general and other useful information. Therefore, I invite you to click on https://hwscience.blogspot.com from time to time to look in what is available.

I will leave space for comments for a while. In case you have specific requests, you are welcome to post them so that I can forward them to Mr Nambane.

My best wishes to all of you and success with your work.

Henry Welman

Congratulations Grade 12 results - 2022

Congratulations to all our teachers and learners with their good grade 12 results of 2022. Free State achieved the best overall results in the country with a pass percentage of 88,5%.

The pass percentages for our subjects were:

• Physical sciences: 80,6% for second place in South Africa.
• Technical sciences: 97,0% for first place in South Africa.

Teachers and learners, thank you for your hard work. Well done!

New Year 2023

I wish each reader a prosperous new year, full of blessings, prosperity, and success!

Enjoy 2023!

Image by Peace,love,happiness from Pixabay

Merry Christmas 2022

Merry Christmas to all the readers and followers of this website. May your day, 25th December 2022, be filled with things that are meaningful to you and your family. All my best wishes. Henry Welman

Holiday wishes for the school holiday

My best wishes to all the readers of this website, but especially to the teachers and learners, for the school holidays. Teachers, thank you for all the "extra miles" you have walked in the interest of our learners. Enjoy the holidays and rest creatively to build up your resources for 2023.

©Image from  https://pixabay.com

Surprises in life!

Surprises in life mean a lot! 

I was so surprised to discover a comment on this website made by an ex-learner quite some time ago. For some or other reason I did not see it until today. 

To this ex-learner of mine, whoever you are, Isa bin Marius, thank you so much! I am nearing the end of my career and such things really mean a lot. To read the comment, click here and scroll down to the bottom of the post. I also enjoyed reading his blog post, which I take the liberty of publishing here. It has appeared in https://contemplationsofarevert.blogspot.com.

Physics - The Roots

Science is a mind-bogglingly wide field of knowledge and research. These people called scientists have measured some wholly inconceivable things, and our present technology is all built on it. But, where did it start? How did we get from "googoo gaga" to knowing the temperature at the core of the Sun?

Well... let's retrace these steps, shall we? What did we know when we knew practically nothing?

Distance is the primary and most obvious thing to measure. Mathematics was basically built on that. One distance being added to another gave us addition. Adding equal distances repeatedly gave us multiplication. Deducting one distance fron another gave us subtraction, and dividing a distance into equal sub-units gave us division. So don't tell me primitive civilisations didn't do math...

Physical science is basically applied mathematics at this point. Also surface area and volume was well understood, since for instance a smaller container obviously contains less water or anything else than a larger one.

Directly related to volume is mass. This is so basic that explaining it would be an outright insult.

The next step is measuring the other constant, obvious factor of life: time. Days, seasons, seasonal cycles. These were then refined into time units more applicable to tasks. An hour as defined today did not exist until very recently, but they did develop a standard unit and sub-units over the course of time.

Next up, "fast" and "slow" was defined by relating the above two measurements. Speed is at times the difference between life and death. Thus, a faster hunter would be superior in gathering food, or escaping from a dangerous animal. The formula was not conceived, but the concept had been born. This also gave rise to the concept of acceleration.

While the formulae were defined later, space, time and mass was well understood on a practical use level. And every kinematic formula can be expressed in terms of only these factors. Take out one, and you're for the most part stuck without an answer.

In conclusion, I'd like to say we are most certainly no better informed than "cavemen" in terms of what we are working with. Our only advantage has ever been that each generation has left applications of this knowledge for the next generation to take for granted and build upon.

So, next time you see your science exam paper, or class test, be assured that your physics are all as simple as space, time and mass.

** A special thanks to Mr Henry Welman who had fed the love of physics in me between the age of 12 and 15.

Sasol's 6th Annual Technical Teacher's Conference

The 6th Annual Technical Teacher's Conference, taking place on 14 and 15 September 2022, will start in a few hours.

For those of you who have not yet registered, click here for the link to register. 

Click here for the programme.

Tips and Tricks for Examination Success

It is almost time for the September (and November) examinations for our grade 12 learners. Here are four booklets with tips and tricks to get the most out of your performance. Grade 10 and 11 learners will also benefit by reading the general issues.

Use the links below the picture to download your own copy of this.

Tips & Tricks for Physical Science in Afrikaans
Tips & Tricks for Physical Science in English

Tips & Tricks for Technical Science in Afrikaans
Tips & Tricks for Technical Science in English

Quantitative Error Analyses: 2022 June Examination Grade 12

 The quantitative error analyses for the grade 12 June examination are available. You will find it under "Pages" and then go to "Error analysis (Quantitative)" or click here. Follow the further links.

Teachers can use this data to identify areas to focus on for the final preparations for these learners.

Teacher Development Classes for Teachers by SAIP & CUT

This programme was cancelled for 2023 due to poor attendance by teachers. More news will follow about future plans.

The South African Institute of Physics (SAIP), in collaboration with the Central University of Technology (CUT), are doing virtual teacher development classes for our teachers on various topics. Although it is a project initiated as support to Free State teachers, other colleagues are welcome to join.

Click here for the full programme. The Zoom link is also embedded in the programme.

Are you ready for the Siyavula challenge?

Are you ready for the Siyavula Challenge?

Click here and click here for full details!

Enjoy!!

Correction of Printing Error

On page 62 of the Terms & Definitions for grade 12 (P2) was a typing error. Learners should correct the typing error in their books. The e-version on this website is correct. It is available here. Follow links from there to the sub-folder "Terms & Definitions". Refer to the pictures below for more detail.

  

How to use Siyavula

The staff at Siyavula has prepared posters to make it easy for teachers how to use the Siyavula resources. The first three posters look like this and below the pictures are links that you can use to download A4 size posters for youself.

Poster 1

Poster 2

Poster 3

Revision Material for Grade 12 Learners

22 final examination papers from DBE and IEB, with worked-out memoranda, explanations and an index to quickly find what you want to revise, are now available to grade 12 learners.

Contact Mrs Engela Steynberg at engelasteynberg@gmail.com

for more information.

Enjoy your exam preparation!

Online Teaching and Resources

The universities of Cape Town and Stellenbosch offer online support material and other services to high school learners and teachers. Click the links below to go to the two websites for more information.

https://www.uctonlinehighschool.com/

https://www.suadvantage.co.za/

Easter 2022

©Image by Gerd Altmann
https://pixabay.com/users/geralt-9301/

I wish all my readers a blessed Easter Weekend. Enjoy it with your families and make it meaningful. May everything that begins on this day of renewal be a reason for great joy throughout the year.

Happy Easter!