南非

Purpose High-jump athletes are not always aware of the exact height they are jumping. They know that they are clearing the height set by the bar, but not their specific height, which may in fact be a record without them even knowing it. The purpose of this project is thus to design and make a device that will enable high-jump athletes to know exactly how high they are jumping. Procedure Background research was conducted and it was confirmed that no similar products are currently available. Possible types of sensors and micro-controllers were then investigated and then both a prototype and model were built to test the concept. Appropriate changes and adjustments were then made to the design until all func-tions were working accordingly. With the assistance of an experienced software de-veloper, a program was designed to communicate the data collected from the sen-sors into a graphical user interface. Results Many variables, contributing to the accuracy of the obtained results, had to be tak-en into consideration. These variables include interference with the sensors, which resulted in less accurate readings, as well as weather conditions. The latter was found not to have as drastic an effect on the results. Conclusion A device that enables athletes to measure the true height they are clearing was suc-cessfully designed and created. This device will thus be able to help motivate athletes by measuring their true capa-bilities.

The focus of this investigation is on how one might be able to reduce the number of accidents and the risk of accidents on our country’s roads by using more reflective products on or in the roads. The reflective products that were used in experimental processes for this investigation were: glass (both brown and clear in colour); oyster shells; reflective paint containing glass beads; glass beads on their own; armour plated glass and a road reflector. These reflective products were compared to a normal tar road and a concrete road

Many people in South Africa still use open fires for cooking. There is a\r large amount of wasted heat lost by four methods of heat transfer:-\r radiation, convection, conduction and evaporation.\r I constructed a vessel that would reduce heat loss, and focus the heat\r emitted from a fire onto the bottom of a pot. I used materials that were\r cheap and easy to obtain, so that those using open fires would be able to\r construct similar vessels to save energy and reduce pollution.\r The vessels were made up of a standard wire mesh frame that was\r surround by trial coverings, namely tin foil, asbestos rope, industrial foil,\r papier mache, ceramic, and 2 ceiling insulators.\r 5 mls of methylated spirits was burned in each vessel. The temperature\r gain of 100mls of water in a standard pot was recorded. 5 trials on each\r vessel were performed. 2 groups of vessel were found. Those that\r produced high temperature gains, burned quickly, and produced a large\r amount of soot deposits on the pot, and a second group that did the\r opposite.\r I compared the rate of heating from my best vessel to that of a stove as\r well as a microwave oven. Heating from the vessel was faster than that of\r the stove, and slightly slower than the microwave.\r I measured the heat emitted from a fire in a three-dimensional pattern and\r found that the maximal heat was some distance above the flame.\r From these results I devised 12 guidelines that would minimize the\r energy need, and pollution produced, when cooking on an open fire

Annually several baby’s and toddlers drown. There are safety devices available on the\r market for ex: Safety nets in which toddlers can get strangled. Pool covers that have to be\r taken off when people swim and replaced after they have swam. If they are not replaced\r afterwards, babies could fall in the water and drown. Fences around the pool:- The gate\r could accidentally be left open and the toddler could fall in and drown.

I made this jet engine to demonstrate how a pulse jet works and to show were the fundamentals of powered aviation all began. I also made this project to gain more knowledge, due to my interests in engineering and turbines. I would also like to measure the thrust of this model in the future. And hopefully this might inspire other people to use this type of engine in their model aircraft.

To compare the habitat and physical\r differences of two burrowing scorpions, Opistophthalmus pugnax and\r the Opistophthalmus glabrifrons to be found in the Gauteng area\r (South Africa). Although these scorpions’ habitat overlaps, they don’t\r co-occur at the same site.

PURPOSE OF THE RESEARCH \r The purpose of this project is to provide a cost-effective and efficient way of \r stripping electrical conductors, with thicknesses of 16mm up to 70mm in diameter, \r of their isolation. The current methods that are available are unsafe and unpractical. \r Therefore this project determines a safe way of stripping cables and also provides a \r new product to improve the worker’s safety during the process of stripping cables. \r PROCEDURES \r The solution can be found by doing research on the types of cable isolations \r currently on the market. By talking to the workers who use these types of tools, and \r strip these types of cables on a daily basis, I can comprehend the problems posed by \r the present methods and provide a solution. \r DATA \r An electrical cable is commonly a conductive wire surrounded by a nonconductive, \r insulation sleeve. In order to splice two cables together or connect the \r cable to an electrical device, the conductive wire inside the sleeve needs to be \r exposed. \r Numerous tools have been developed for slitting and stripping the electrical \r cable in order to expose the said conductive wire. The simplest tool is a knife with \r which the user makes an annular cut in the sheathing. The end portion of the \r sheathing then is pulled away exposing the individually insulated wires and the bare \r ground wire. The knife may also be used to cut away a short portion of the \r insulation at the ends of the wires. During both operations the user has to be \r extremely careful, or else the knife blade may damage the insulation around the \r internal wires and even nick the conductor or he may injure himself. To do so the \r user must first cut away several inches of the plastic sheathing at the end of the \r cable. A short length of the insulation then is removed from around each end of the \r conductors. \r As an alternative to using a knife, various scissors-like wire strippers have been \r developed. Although such scissors-like wire strippers are effective for removing the \r insulation from individual wires within an electrical cable, they are not efficient for \r removing the sheathing from the end of the cable in order to expose the individually \r insulated wires. \r A disadvantage of using a conventional knife and with using the known wire \r stripper is that a cable having a relatively thick insulation sleeve is difficult to strip \r and thus prepare for connections, since conventional wire stripping tools and other \r conventional devices, such as knives or tools with enclosed blades are inefficient for \r stripping thicker cable jackets. \r A further disadvantage of the known wire strippers is that, its basic \r characteristic dictates that the degree of friction between the tool and the wire after \r the insulation has been ringed will be high. This occasions no particular difficulty \r when only a short length of insulation is to be removed from the end of the wire. \r However, when yards and yards of insulation are to be stripped, as may be the case \r when reel ends are to be prepared for scrapping, the conventional wire stripper \r generates so much friction that it cannot be efficiently utilised. \r CONCLUSION \r The developed product enables workers to effectively strip electrical \r conductors without any impeding danger to themselves or the risk of damaging said \r cable. It is cost-effective and saves a lot of time. After several tests of the product no \r problems have been encountered up to this point.

Purpose of the research Experiments were performed to determine if the frequencies of the colours of pigment differ from the frequencies of the colours of filtered light. The third experiment was performed to determine whether the different colours of filtered light have an influence on plant growth. Procedures Experiments I and II were performed in sunlight and the temperatures of different colours of paper, as well as a white paper underneath different colours of transparencies, were measured by means of an infrared thermometer. The Stefan-Boltzmann equation was used for calculations. Experiment III was performed by placing ten spinach seedlings under each of the Code 40 red, green, blue and black/white shade nets. The control, 10 spinach seedlings, had no Code 40 shade net covering. All these spinach seedlings were grown under similar conditions and harvested after 4 weeks. Data In Experiment I the yellow paper was the only colour that did not perform according to the sequence of the white light spectrum (ROYGBIV). The temperature of the different colours of paper determined the amount of energy that was re-emitted. In Experiment II it was determined that the primary colours red, green and blue, as well as yellow of the filtered light, performed according to the white light spectrum. In Experiment III the spinach plants underneath the blue shade net have the highest average fresh mass (g), as well as the largest average leaf area (cm2), while the spinach plants underneath the red shade net have the lowest average fresh mass (g), as well as the smallest average leaf area (cm2). Conclusions In Experiment I the primary colours of the white light spectrum are red, green and blue. When red and green are combined, yellow is obtained. Therefore the temperature of the yellow paper was lower than expected, because only blue light was absorbed, while red, green and yellow light were reflected. In Experiment II all the colours of the transparencies performed according to ROYGBIV. By comparing the amount of energy of the colours of pigment to the colours of the filtered white light spectrum, it became apparent that there is a difference between the frequencies of the colours of pigment and the frequencies of the colours of filtered white light spectrum.