Solar ray collector
Principle The solar ray collector is illuminated with a halogen lamp of known light intensity. The heat energy absorbed by the collector can be calculated from the volume flow and the difference in the water temperatures at the inlet and outlet of the absorber, if the inlet temperature stays almost constant by releasing energy to […]
Thermal expansion in solids and liquids
Principle The volume expansion of liquids and the linear expansion of various materials is determined as a function of temperature. Benefits With detailed experiment guide Two experiments in one Tasks To determine the volume expansion of ethyl acetate (C4H8O2), methylated spirit, olive oil, glycerol and water as a function of temperature, using the pycnometer. To determine […]
Adiabatic coefficient of gases – Flammersfeld oscillator
Principle A mass oscillates on a volume of gas in a precision glass tube. The oscillationis maintained by leading escaping gas back into the system. The adiabatic coefficient of various gases is determined from the periodic time of the oscillation. Benefits Suitable for many different gases Compact, easily transportable setup Tasks Determine the adiabatic coefficient […]
Thermal equation of state and critical point
Principle A substance which is gaseous under normal conditions is enclosed in a variable volume and the variation of pressure with the volume is recorded at different temperatures. The critical point is determined graphically from a plot of the isotherms. Benefits Visualization of the critical point Tasks Measure a number of p-V isotherms of ethane. […]
Heat capacity of gases with Cobra4
Principle Heat is added to a gas in a glass vessel by an electric heater which is switched on briefly. The temperature increase results in a pressure increase, which is measured with a manometer. Under isobaric conditions a temperature increase results in a volume dilatation, which can be read from a gas syringe. The molar […]
Vapour pressure of water below 100°C – molar heat of vaporisation
Principle The vapour pressure of water in the range of 40 °C to 85 °C is investigated. It is shown that the Clausius-Clapeyron equation describes the relation between temperature and pressure in an adequate manner. An average value for the heat of vaporisation of water is determined. Benefits Compact, easily transportable setup For both demonstration […]
Emittance of hot bodies (Leslie cube)
Principle Thermal radiation can be measured at all surfaces as long as their temperature differs from that of the surrounding. Therefore it applies that the hotter an object is, the more radiation it emits. Also the surface colour influences the behaviour: dark surfaces emit more thermal radiation than light ones. An example for application of […]
Electric compression heat pump
Principle Pressures and temperatures in the circulation of the heat electrical compression heat pump are measured as a function of time when it is operated as a water-water heat pump. The energy taken up and released is calculated from the heating and cooling of the two water baths. When it is operated as an air-water […]
Semiconductor thermogenerator – Seebeck effect
Principle In a semi-conductor thermogenerator, the no-load voltage and the short-circuit current are measured as a function of the temperature difference. The internal resistance, the Seebeck coefficient and the efficiency are determined. Benefits Open design allows to fully understand function and applications Individual instruments for distinct functions (no “black box”) Key products of the experiment […]
Thermal and electrical conductivity of metals
Principle The thermal conductivity of copper and aluminium is determined in a constant temperature gradient from the calorimetrically measured heat flow. The electrical conductivity of copper and aluminium is determined and the Wiedmann-Franz law is tested. Benefits Measurement of electrical and thermal conductivity in one set-up Compact, easily transportable setup Tasks Determine the heat capacity […]
Peltier heat pump
Principle The (cooling capacity) heating capacity and efficiency rating of a Peltier heat pump are determined under different operating conditions. Benefits Open design allows to fully understand function and applications Individual instruments for distinct functions (no “black box”) Key products of the experiment setup can also be used for investigating the Seebeck effect Tasks To determine the […]
Stefan-Boltzmann’s law of radiation with an amplifier
Principle According of Stefan-Boltzmann’s law, the energy emitted by a black body per unit area and unit time is proportional to the power “four” of the absolute temperature of the body. Stefan-Boltzmann’s law is also valid for a so-called “grey” body whose surface shows a wavelength independent absorption-coefficient of less than one. In the experiment, […]
Cooling by evacuation
Principle When the air pressure above a watersurface is reduced, the water begins to boil at a certain temperature. The temperature of the water is hereby reduced and further evacuation can finally bring it to 0 °C and even lower. Benefits Data logging via tablet possible. For both demonstration and student experiments Tasks Determine the […]
Mechanical equivalent of heat
Principle In this experiment, a metal test body is rotated and heated by the friction due to a tensed band of synthetic material.The mechanical equivalent of heat for problem 1 is determined from the defined mechanical work and from the thermal energy increase deduced from the increase of temperature. Assuming the equivalence of mechanical work […]
Heat capacity of metals
Principle Heated specimens are placed in a calorimeter filled with water at low temperature. The heat capacity of the specimen is determined from the rise in the temperature of the water. Benefits Compact, easily transportable setup For both demonstration and student experiments Tasks To determine the heat capacity of the calorimeter by filling it with […]
Heat capacity of metals with Cobra4
Principle Heated specimens are placed in a calorimeter filled with water at low temperature. The heat capacity of the specimen is determined from the rise in the temperature of the water. Benefits Flexible experimenting thanks to wireless data transmission Data acquisition with tablets possible Simplified implementation: all pre-settings already prepared Tasks To determine the specific […]
Joule-Thomson effect
Principle A stream of gas is fed to a throttling point, where the gas (CO2 or N2) undergoes adiabatic expansion. The differences in temperature established between the two sides of the throttle point are measured at various pressures and the Joule-Thomson coefficients of the gases in question are calculated. Benefits For both demonstration and student experiments With […]
Heat capacity of gases
Principle Heat is added to a gas in a glass vessel by an electric heater which is switched on briefly. The temperature increase results in a pressure increase, which is measured with a manometer. Under isobaric conditions a temperature increase results in a volume dilatation, which can be read from a gas syringe. The molar […]
Vapour pressure of water at high temperature
Principle The high-pressure steam apparatus makes it possible to measure steam pressure in a temperature range of 100-250 °C. This allows for investigations to be performed on real gases and vapours. Typical equilibrium states between gas and liquid phases can be set up. For this purpose, water is heated in a closed pressure chamber at […]
Maxwellian velocity distribution
Principle By means of the model apparatus for kinetic theory of gases the motion of gas molecules is simulated and the velocities determined by registration of the throw distance of the glass balls. This velocity distribution is compared to the theoretical Maxwell- Boltzmann equation. Benefits For both demonstration and student experiments Unique experiment to quantitatively […]
Equation of state for ideal gases with Cobra4 (gas laws: Gay-Lussac, Amontons, Boyle)
Principle The state of a gas is determined by temperature, pressure and amount of substance. For the limiting case of ideal gases, these state variables are linked via the general equation of state. For a change of state under isochoric conditions this equation becomes Amontons’ law. In this experiment it is investigated whether Amontons’ law […]