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Rijke Tube
The Rijke tube is a cylindrical tube with both ends open, inside of which a heat source is placed that turns heat into sound, by creating a self-amplifying standing wave. It is an entertaining phenomenon in acoustics and is an excellent example of resonance. Discovery Pieter Rijke, P. L. Rijke was a professor of physics at the Leiden University in the Netherlands when, in 1859, he discovered a way of using heat to sustain a sound in a cylinder (geometry), cylindrical tube open at both ends. He used a glass tube, about 0.8 m long and 3.5 cm in diameter. Inside it, about 20 cm from one end, he placed a disc of wire gauze as shown in the figure on right. Friction with the walls of the tube is sufficient to keep the gauze in position. With the tube vertical and the gauze in the lower half, he heated the gauze with a flame until it was glowing red hot. Upon removing the flame, he obtained a loud sound from the tube which lasted until the gauze cooled down (about 10second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat
In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is also often used to refer to the thermal energy contained in a system as a component of its internal energy and that is reflected in the temperature of the system. For both uses of the term, heat is a form of energy. An example of formal vs. informal usage may be obtained from the right-hand photo, in which the metal bar is "conducting heat" from its hot end to its cold end, but if the metal bar is considered a thermodynamic system, then the energy flowing within the metal bar is called internal energy, not heat. The hot metal bar is also transferring heat to its surroundings, a correct statement for both the strict and loose meanings of ''heat''. Another example of informal usage is the term '' heat content'', used despite the fact that p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borosilicate Glass
Borosilicate glass is a type of glass with silica and boron trioxide as the main glass-forming constituents. Borosilicate glasses are known for having very low coefficients of thermal expansion (≈3 × 10−6 K−1 at 20 °C), making them more resistant to thermal shock than any other common glass. Such glass is subjected to less thermal stress and can withstand temperature differentials without fracturing of about . It is commonly used for the construction of reagent bottles and flasks as well as lighting, electronics, and cookware. Borosilicate glass is sold under various trade names, including Borosil, Duran, Pyrex, Glassco, Supertek, Suprax, Simax, Bellco, Marinex (Brazil), BSA 60, BSC 51 (by NIPRO), Heatex, Endural, Schott, Refmex, Kimax, Gemstone Well, and MG (India). Single ended self-starting lamps are insulated with a mica disc and contained in a borosilicate glass gas discharge tube (arc tube) and a metal cap. They include the sodium-vapor lamp tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The inverse of the wavelength is called the spatial frequency. Wavelength is commonly designated by the Greek letter ''lambda'' (λ). The term ''wavelength'' is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths. Wavelength depends on the medium (for example, vacuum, air, or water) that a wav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Working Of Rijke Tube
Working may refer to: * Work (human activity), intentional activity people perform to support themselves, others, or the community Arts and media * ''Working'' (musical), a 1978 musical * ''Working'' (TV series), an American sitcom * ''Working'' (Caro book), a 2019 book by Robert Caro * ''Working'' (Terkel book), a 1974 book by Studs Terkel * ''Working!!'', a manga by Karino Takatsu * "Working" (song), by Tate McRae and Khalid, 2021 Engineering and technology * Cold working or cold forming, the shaping of metal below its recrystallization temperature * Hot working, the shaping of metal above its recrystallization temperature * Multiple working, having more than one locomotive under the control of one driver * Live-line working, the maintenance of electrical equipment while it is energised * Single-line working, using one train track out of two Other uses * Holbrook Working (1895–1985), statistician and economist * Working the system, exploiting rules and procedures for un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Theophil Riess
Peter Theophil Riess (27 June 1804 – 22 October 1883) was a German physicist, known mostly for his work in electricity, particularly friction electricity, but also in the field of electromagnetic induction. In the latter work he developed two devices, the spark micrometer (sometimes called the Riess micrometer) and the Riess spiral coils, both of which were used by Heinrich Hertz in his experiments to prove the propagation of electromagnetic waves. Riess was the son of a wealthy jeweller in Berlin. He received his doctorate in 1831 from the University of Berlin. In the early years after graduation he stayed with his father who was ill and helped run the business. Even after his father died, he never sought an academic teaching position. However he was a fellow (Mitglied) of the Berlin Academy, the first Jewish member of that academy, and under its auspices, and within its journal, Riess published prolifically. He also published several books, as well as many articles in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in front of oxygen (32.1% and 30.1%, respectively), forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust. In its metallic state, iron is rare in the Earth's crust, limited mainly to deposition by meteorites. Iron ores, by contrast, are among the most abundant in the Earth's crust, although extracting usable metal from them requires kilns or furnaces capable of reaching or higher, about higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BCE and the use of iron tools and weapons began to displace copper alloys, in some regions, only around 1200 BCE. That event is considered the transition from the Bronze Age to the Iron A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cast Iron
Cast iron is a class of iron–carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impurities which allow cracks to pass straight through, grey cast iron has graphite flakes which deflect a passing crack and initiate countless new cracks as the material breaks, and ductile cast iron has spherical graphite "nodules" which stop the crack from further progressing. Carbon (C), ranging from 1.8 to 4 wt%, and silicon (Si), 1–3 wt%, are the main alloying elements of cast iron. Iron alloys with lower carbon content are known as steel. Cast iron tends to be brittle, except for malleable cast irons. With its relatively low melting point, good fluidity, castability, excellent machinability, resistance to deformation and wear resistance, cast irons have become an engineering material with a wide range of applications and are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lecture
A lecture (from Latin ''lēctūra'' “reading” ) is an oral presentation intended to present information or teach people about a particular subject, for example by a university or college teacher. Lectures are used to convey critical information, history, background, theories, and equations. A politician's speech, a minister's sermon, or even a business person's sales presentation may be similar in form to a lecture. Usually the lecturer will stand at the front of the room and recite information relevant to the lecture's content. Though lectures are much criticised as a teaching method, universities have not yet found practical alternative teaching methods for the large majority of their courses. Critics point out that lecturing is mainly a one-way method of communication that does not involve significant audience participation but relies upon passive learning. Therefore, lecturing is often contrasted to active learning. Lectures delivered by talented speakers can be high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lord Rayleigh
John William Strutt, 3rd Baron Rayleigh, (; 12 November 1842 – 30 June 1919) was an English mathematician and physicist who made extensive contributions to science. He spent all of his academic career at the University of Cambridge. Among many honors, he received the 1904 Nobel Prize in Physics "for his investigations of the densities of the most important gases and for his discovery of argon in connection with these studies." He served as president of the Royal Society from 1905 to 1908 and as chancellor of the University of Cambridge from 1908 to 1919. Rayleigh provided the first theoretical treatment of the elastic scattering of light by particles much smaller than the light's wavelength, a phenomenon now known as "Rayleigh scattering", which notably explains why the sky is blue. He studied and described transverse surface waves in solids, now known as "Rayleigh waves". He contributed extensively to fluid dynamics, with concepts such as the Rayleigh number (a dimensio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilowatt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Watt (1736–1819), an 18th-century Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own steam engine in 1776. Watt's invention was fundamental for the Industrial Revolution. Overview When an object's velocity is held constant at one metre per second against a constant opposing force of one newton, the rate at which work is done is one watt. : \mathrm In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical circuit). : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Current (electricity)
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes. In an electrolyte the charge carriers are ions, while in plasma, an ionized gas, they are ions and electrons. The SI unit of electric current is the ampere, or ''amp'', which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit. Electric current is measured using a device called an ammeter. Electric currents create magnetic fields, which are used in motors, generators, inductors, and transformers. In ordinary conduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
