Make a sundial for Johannesburg
Save the below image & print and paste the image below onto a piece of cardboard. Mount it according to the instructions printed on the dial. You now have a sundial for Johannesburg.
Shocking facts about electricity
(Original source unknown) Today's scientific question is: What in the world is electricity? And where does it go after it leaves the toaster? Here is a simple experiment that will teach you an important electrical lesson: On a cool, dry day, scuff your feet along a carpet, then reach your hand into a friend's mouth and touch one of his dental fillings. Did you notice how your friend twitched violently and cried out in pain? This teaches us that electricity can be a very powerful force, but we must never use it to hurt others unless we need to learn an important electrical lesson. It also teaches us how an electrical circuit works. When you scuffed your feet, you picked up a batch of "electrons," which are very small objects that carpet manufacturers weave into carpets so they will attract dirt. The electrons travel through :your bloodstream and collect in your finger, where they form a spark that leaps to your friend's filling, then travel down to his feet and back into the carpet, thus completing the circuit.
AMAZING ELECTRONIC FACT: If you scuffed your feet long enough without touching anything, you would build up so many electrons that your finger would explode! But this is nothing to worry about, unless you have carpeting. Although we modern persons tends to take our electric lights, radios, mixers, etc. for granted, hundreds of years ago people did not have any of these things, which is just as well because there was no place to plug them in. Then along came the first Electrical Pioneer, Benjamin Franklin, who flew a kite in a lightning storm and received a serious electrical shock. This proved that lightning was powered by the same force as carpets, but it also damaged Franklin's brain so severely that he started speaking only in incomprehensible maxims, such as, "A penny saved is penny earned." Eventually, he had to be given a job running the post office. After Franklin came a herd of Electrical Pioneers whose names have become part of our electrical terminology: Myron Volt, Mary Louise Amp, James Watt, Bob Transformer, etc. These pioneers conducted many important electrical experiments. For example, in 1780 Luigi Galvani discovered (this is the truth) that: when he attached two different kinds of metal to the leg of a frog, an electrical current developed and the frog's leg kicked, even though it was no longer actually attached to the frog, which was dead anyway. Galvani's discovery led to enormous advances in the field of amphibian medicine. Today, skilled veterinary surgeons can take a frog that has been seriously injured of killed, implant pieces of metal in its muscles, and watch in hop back into the pond just like a normal frog, except for the fact that it sinks, like a stone. But the greatest Electrical Pioneer of all was Thomas Edison, who was a brilliant inventor despite the fact that he had little formal education and lived in New Jersey. Edison's first major invention, in 1877, was the phonograph, which could soon be found in thousands of American homes, where it basically just sat until 1923, when the record was invented. But Edison's greatest achievement came in 1879, when he invented the electric company. Edison's design was a brilliant adaptation of the simple electrical circuit: The electric company sends electricity through a wire to a customer, then immediately gets the electricity back through another wire, then (this is the brilliant part, sends it right back to the customer again. This means that an electric company can sell a customer the same batch of electricity thousands of times a day and never get caught, since very few consumers take the time to examine their electricity closely. In fact, the last year in which any new electricity was generated in the United States was 1937: the electric companies have been merely re-selling it ever since, which is why they have so much free time to apply for rate increases. Today, thanks to men like Edison and Franklin, and frogs like Galvani's, we receive almost unlimited benefits from electricity. For example, in the past decade scientists developed the laser, an electronic appliance that emits a beam of light so powerful that it can vaporise a bulldozer 2,000 yards away yet so precise that doctors can use it to perform delicate operations on the human eyeball, provided they remember too change the power setting from "VAPORIZE BULLDOZER" to "DELICATE."
Working with electricity can be a complex task indeed. There are many different kinds of electricity: luminous electrons for lighting, coloured electrons for television, cold and hot electrons for refrigerators or stoves respectively, et cetera. To confuse one sort of electricity with another can have catastrophic results in the kitchen. There is also portable electricity, which has to be put in batteries before it can be used. For small batteries (e.g. the ones used in a hearing aid) this is best done with a pair of tweezers. Larger batteries can be filled with a shovel. Electricity comes in two main flavors: DC (direct current) and AC (alternating current). Direct Current always runs through the wires in the same direction (from plus to minus) while AC runs back and forth all the time without really getting anywhere. Still it works, which is a bit of a mystery. A little-known fact about AC is that it comes in two different polarizations: horizontal for use in level areas, and vertical for use in mountain regions. Even today electricity still hasn't yielded up all its mysteries. For example, how do the electrons running through your toaster know when the toast is done?
"Frequency" and ZS6HVB
Ham radio truimphs again
When it was announced that the film "Frequency" was to be shown here in South Africa, my secretary, Gerry Capper ZS6GMJ contacted me (Ton van Dijk ZS6ANA, chairman of ZS6HVB) and said that he wanted to put up a station at the Bedford Center in Johannesburg. I thought that was an excellent idea and we set to work. Henry ZS6GH contacted Hans ZS5AKV and the wheels started rolling. Gerry and I got together and we decided what we should all take with us for that weekend at the NU METRO CINEMA.
On Monday the 17th of June we went to speak to the cinema manager who did not know anything about our intended Ham Station installation. He duly got the approval from his Head Quarters and we were given the 'Go Ahead' signal. We looked all over the cinema for the shortest rout to the roof and found that it would be about 60 meters for each feed line. On Thursday the 20th we installed the antennas, for HF, Packet Radio and for VHF and UHF. During the three days Friday, Saturday and Sunday, 21, 22 and 23 July we had lots of visits from the public as well as from Hams, we even gota visit from ZS1MAL from Cape Town. The highlight of the weekend was a visit from a young boy by the name of Devan Heystek,
This young boy was so delighted with our setup that he would not leave and spent most of Saturday with us. His parents left him with us. The last Day was Sunday and just after we arrived at the theater, who came along? It was Devan. We were not surprised at his joining us again for the day. This young fellow had so much fun talking to other people that he has decided to become a Radio Ham. A 2meter rig has already been donated to him by ZR6PDT. I will make sure that it will only receive signals and will supply some repeater frequencies for him to listen to.
Ham Radio will grow. ZS6ANA Ton van Dijk