As soon as we have assembled a simple compass made of plastic and needle, we have quickly spent several times on a metal sewing needle with the magnet strictly in one direction. This action caused the needle to become temporarily magnetized and turned into a simple analog of a two-pole magnet. In particular, our metal needle acquired one magnetized end — the one to which the magnet was moved — and one non-magnetized (Woodford, 2019). When the plastic with the magnetized needle was placed on the water surface, it could move freely but was positioned strictly according to the Earth’s magnetic field. Thus, the magnetized end of the needle, its tip, was turned towards the geographic North Pole. This phenomenon is also confirmed by the fact that when trying to turn the plastic, it still returned to the set position.
Introducing a permanent magnet into the area of our plastic disk noticeably changes the established situation. This phenomenon is very similar to how a metal sewing needle reacted to the Earth’s field, but instead of a planetary field, we use a permanent magnet with poles set: North and south. Thus, there is a positive charge at the south pole, while at the north pole, there is a negative charge. If we bring the magnet to the south side’s structure, the needle on the disk will be oriented towards the magnet because the magnetic field of the material will be larger than the field of the Earth. The needle, with its sharp end, will follow the magnet as it rotates around the plate. On the other hand, if we bring the magnet to the needle with the north side, we get the interaction of different shaped charges, which leads to an independent rotation of the needle by 180 degrees.
In this laboratory work, an experiment was conducted to determine the effect of sunlight on the drying of fabric material. In particular, four samples of cotton fabric of the same size and thickness were used. All fragments were placed for two minutes in a water plate to allow the material to become completely wet. The fabric was then squeezed out and placed on a window sill so that the two samples were exposed to direct sunlight, and the two remained in the shade. The final interest was the drying time of the fabrics, depending on their position. A stopwatch was used to estimate the time. Thus, both samples of wet fabric under direct sunlight dried entirely within 15 minutes, while the “shadow” fabrics took about 27 minutes. This conclusion supports the hypothesis that sunlight directed at the fabric stimulates faster drying.
However, it would be erroneous to believe that only sunlight affects the speed at which the material dries. Actually, if to leave two identical on the size, but different on chemical structure, materials under the sun, they will not necessarily dry out equally quickly. In other words, the composition of the material plays an essential role in assessing the speed of drying (Forno, 2018). On the other hand, the drying speed is also influenced by the ambient air temperature: due to the presence of solar energy, the temperature outside is higher. In addition, air circulation is also important, since the more often a room is ventilated, the higher the drying speed. If more materials need to be dried, it is optimal to hang them loosely: free placement allows for faster drying. Finally, there is a direct link between the material area and the drying speed. A smaller piece of fabric will dry noticeably faster than its large analog.
Given that solar energy has developed actively in recent decades, there are ways for households to save energy by using solar panels. If resources and finances are available, it is possible to place the solar panel on a sloping roof surface so that as many rays as possible can reach the panel during the day. The conductor contacts collect the electricity from the panel into a distributor, from where it is carried around the house. This approach solves the problem of savings in water heating, heating, home lightbulbs, and other consumer electronics. On the other hand, if we do not have sufficient resources to accommodate the solar panel, that is, other ways to save. For example, to heat food, we can replace the microwave with a plate in the sun. We can also place a water tank outside the house, which will be heated during the day. In addition, there are already many examples of electronic devices with built-in mini panels that generate energy. For example, we can use wireless chargers, fans, or lighting fixtures.
In this experiment, electrostatic forces were not generated when the transparent tape was slowly removed from the roll or placed on a dry surface. On the contrary, when two fragments of tape were combined with the adhesive side, charges were redistributed: the original neutrally charged pieces of tape acquired opposite charges (Tribonet, 2019). The fragment from above could become positively charged, while the transparent tape from below had an abundance of electrons possibly. When contact between them is broken, the distance between surfaces sharply increased, and an electric field was formed. Obviously, when the fragments are turned to a smooth surface and come into contact with it, they will be attracted, for as physics postulates, the opposite charges are attracted to each other.
In the second case, no strong adhesion was observed between the two transparent tape pieces, as there was no significant triboelectric effect. In particular, identical pieces of duct tape were placed on the same surface apart from one another. Indeed, some electrification could have occurred when the table surface was detached, but it seemed insignificant for this experience. In addition, even if such contact electrification had transpired, both pieces of scotch would have been charged equally. Nevertheless, two pieces of matter connected by smooth sides showed no connection. This was due to the fact that both fragments still had the same charges, and therefore were not attracted.
First of all, it is necessary to calculate the amount of potential energy needed to climb ten steps. The following formula is used for the calculation:
Consequently, the number of watts that were spent on running can be calculated by the formula:
Given the textbook information, this is the average amount of energy that a person can spend in a short time. Probably a relatively high number was caused by a sharp start and running at the limit of possibilities. However, as can be seen from the formulas above, it is possible to increase the watts produced by the body in several ways. These include shortening the running time, increasing body weight (with weights, for example), choosing higher steps. In particular, if one increases the weight up to 80 kg, step height up to 4 meters, and reduces the running time to 3 seconds, the number of watts will be equal to 1045, which is already exceeding the possible limit.
Convection is an essential phenomenon in heat exchange, which finds its application not only in industrial production but also in cooking and heating of rooms. When the black pepper particles settled at the bottom of transparent glass, a flame of fire was brought to the outside of the container to heat the water. As a result, warm streams of water began to form, which, according to the principles of convection, have a lower density, and consequently, rise upwards. Their strength is enough to make the pepper particles spin around the mug, as shown in the figure below. At the same time, the water that has been lifted cools down and then falls again. Similar circulating forces are also detected as the candle fades when the noticeable grey smoke begins to rise sharply upwards. The smoke is the heated air, which has a lower density and therefore rises more. The cold currents of ambient air allow to maintain the smoldering, as they fall on the wick, are heated, and rise again upwards. The fact that paraffin hardens overtime is justified by the presence of cold currents.
However, the convection phenomenon is also found in the wild: many soaring birds do not make any visible wing efforts but remain in the air. This effect is confirmed by convection forces, which lift warm air above the atmosphere. Birds with broad open wings “lie” on warm currents, which allow them not to lower their height. Most likely, such air currents are formed by evaporation of water from water bodies or land surface. On the other hand, the constant emission of gaseous waste, smog, and warm carbon dioxide can also affect birds’ floating.
References
Forno, S. (2018). The best, quick-dry travel fabrics: A buyer’s guide. Tortuga. Web.
Tribonet. (2019). Triboelectricity. About Tribology. Web.
Woodford, C. (2019).Magnetism. Explain That Stuff. Web.