Table of Thermodynamics Thermodynamics (4A): Thermal Properties of Matter Thermodynamics (4C): Change of State Lecture Demonstrations

## Heat and the First Law

PIRA classification 4B

 Grayed Demos are either not available or haven't been built yet.

# 4B20. Convection

 PIRA # Demonstration Name Abstract 4B20.10 convection tube Heat one side of a glass tube loop filled with water and insert some food coloring. 4B20.20 two chimney convection box A candle burns under one chimney in a double chimney convection box. Smoke is used to indicate convection in the two chimney box. 4B20.25 convection chimney with vane A candle in a chimney burns as long as there is a metal vane dividing the chimney into two parts. 4B20.30 convection chimney with confetti 4B20.40 convection projection cell An electric element heats water in the bottom of a projection cell. Diagram. 4B20.41 convection box Shadow project convection in a 1 foot square box with hot and cold sinks on the sides. 4B20.42 projection cell Introduce hot water at the bottom of cold or cold water at the top of warm in a projection cell. 4B20.45 burn your hand Shadow project a Bunsen burner flame on a screen and hold your hand in the hot gas. Use a Bunsen burner, a hot pipe, dry ice, or ice water. 4B20.50 Barnard cell A thin layer of paraffin with reflective aluminum flakes is heated until Barnard cells, or convection cells form.

# 4B30. Conduction

 PIRA # Demonstration Name Abstract 4B30.10 conduction - dropping balls Waxed balls drop off various metal rods connected to a heat source as the heat is conducted. Waxed balls drop at different times from rods attached to a common heat source. 4B30.11 conduction - dropping balls The center of a star configuration of five different metal bars is heated to melt wax at the far ends, dropping balls. 4B30.12 thermal conductivity Dip rods in wax, then watch as the wax melts off. Time Lapse. 4B30.15 sliding pointers Vertical rods of different metals are soldered onto the bottom of a vessel filled with boiling water. Pointers held by some paraffin slide down as the rods heat. Diagram. 4B30.20 painted rods Rods of different material are coated with heat sensitive paint and attached to a common heat source. Steam is passed through a manifold with heat sensitive paint coated rods of different materials. 4B30.21 conduction bars Relative conductivities of bars of metals in a common copper block are indicated by match head ignition or temperature indicating paint. 4B30.22 iron and copper strips Iron and copper strips are coated with "thermal color" and heated at one end. 4B30.25 four rods - heat conduction 4B30.30 copper and stainless tubes A contest is held between people holding copper and stainless tubes in twin acetylene torch flames. 4B30.31 poor thermal conduct. of stainless s Heat a stainless rod/tube with a blow torch until it is white hot and hold the other end. 4B30.32 iron and aluminum rods A student holds iron and aluminum rods in a burner flame. 4B30.35 toilet seats 4B30.40 wood and metal rod Wrap a paper around a rod made of alternating sections of wood and metal and hold in a flame. 4B30.42 matches on hot plates Matches are placed on plates of two different metals over burners. 4B30.50 heat propagation in a copper rod Solder a copper-constantan thermocouple into a copper rod and thrust the end into a flame. 4B30.51 spreading heatwave An aluminum bar has a series of small mirrors mounted on small bimetallic strips to allow projection of the curve of the temperature in the bar as it is heated. Construction details in appendix, p.1287. 4B30.53 liquid crystal indicator Liquid crystal indicator from Edmund Sci. was bonded to a strip and a plate of metal and the resulting color change compared well with a computer generated model. A copper bar is placed on temperature indicating paper and one end is heated. See AJP 41(2),281 4B30.54 heat transfer A solid copper rod has holes bored to pass steam and cold water from the same end. Thermometers along the rod measure the heat transfer into the water. 4B30.56 anisotropic conduction Conductivity is greater along the grain in wood and crystals. Heat the center of a thin board covered with a layer of paraffin and watch the melting pattern. 4B30.58 thermal vs. electrical conduction A rod is fabricated with end sections of copper and a center section of constantan. Temperatures along the rod when heated differentially are compared with voltages along it while a potential is applied. 4B30.59 electrical analog of heat flow A circuit that gives the electrical analog of heat conduction. See AJP 29(8),549 4B30.60 heat conductivity of water Boil water in the top of a test tube while ice is held at the bottom. 4B30.61 heat conductivity of water The bulb of a hot air thermometer is placed in water and a layer of inflammable liquid is poured on top and burned. 4B30.65 heat conduction in gases Small double walled flasks are filled with ether, the jackets contain different gases. When placed in boiling water, the height of ether flames varies. 4B30.66 heat conductivity of CO2 Author tried using dry ice to cool break the bolt. Nothing happened. See AJP 29(8),549 4B30.71 conduction of heat in a lamp A carbon filament lamp is filled with different gases at various pressures and the brightness of the filament observed. 4B30.72 glowing tubes Filaments in Pyrex tubes containing air, flowing hydrogen, and hydrogen at reduced pressure glow with different intensities. Picture. 4B30.73 double glow tube A single length of Nichrome wire runs through two chambers allowing comparison of thermal conductivity of two gases and variation of pressure.

# 4B50. Heat Transfer Applications

 PIRA # Demonstration Name Abstract 4B50.10 four thermos bottles Monitor the temperatures of water in four thermos bottles with different combinations of vacuum and silvering. Hot water is placed in the four thermos bottles. 4B50.11 bad dewar Evacuate a unsilvered dewar, pour in liquid air, let air into the space, see frost form. 4B50.15 four thermos bottles - LN2 Pour liquid air into four thermos bottles to sort out conduction, convection and radiation. 4B50.20 boiling water in a paper cup Burn one paper cup, boil water in another. Fill a KFC bucket 1/8 full of water, boil the water with a Bunsen burner, and burn away the top part of the bucket with a propane torch. 4B50.20 insulation with asbestos Fight asbestos abatement. Three cans, black, asbestos covered, and shiny, are filled with boiling water and left to cool. An asbestos paper covered can cools faster than a shiny can. 4B50.25 water balloon heat capacity Pop a balloon with a flame, then heat water in another balloon. 4B50.30 Leyden frost phenomenom Drop water on a hot plate, liquid nitrogen on the lecture table. 4B50.31 spheroidal state A nugget of silver heated red and plunged into water does not cause immediate boiling. 4B50.32 spheroidal state A drop of water suspended from a glass tube above a hot plate is stable until the plate cools. See AJP 46(8),825 4B50.32 Leyden frost effect Pour liquid air on your hand or roll it about on the top of your tongue. 4B50.35 finger in oil Heat oil in a beaker, cut a potato and cook a french fry, then wet you finger in a beaker of water and stick it in the hot oil. 4B50.35 spheroidal state A wet finger can be dipped into molten lead. 4B50.40 reverse Leyden frost effect Place a brass ball into liquid air in a clear dewar and observe the initial leidenfrost effect. When the ball is cold, place it in a flame and observe the reverse leidenfrost effect as frost forms on the ball while it is in the flame. 4B50.60 greenhouse effect The temperature of a closed bottle in direct sunlight is compared to the ambient temperature. A chamber with interchangeable windows and provisions to introduce CO2. See AJP 41(3),443 4B50.62 radiation and convection Put a hot metal object in a smoke filled projection cell and the smoke will be repelled by radiation pressure. Convection will cause an upward clearing. 4B50.70 Davy lamp A Bunsen burner will burn on top and bottom of two copper screens a few inches apart. Show that a Bunsen burner flame will not strike through to the other side of fine copper wire gauze. Direct a stream on gas at a lit Davy safety lamp. 4B50.80 conduction and convection - Pirani The basic principles of the Pirani vacuum gauge. Heat a platinum wire in a flask until it glows dull red, then evacuate the flask and the wire will glow more brightly at the same voltage.

# 4B60. Mechanical Equivalent of Heat

 PIRA # Demonstration Name Abstract 4B60.10 heating lead shot in a bag A bag of lead shot is dropped several times and the temperature rise is measured. A diagram of a projection thermometer is given. 4B60.11 mechanical equivalent of heat Flip a one meter tube containing lead shot ten times. A thermistor embedded in one end measures the temperature. 4B60.12 heating mercury by shaking A nichrome - iron wire thermojunction is inserted into a bottle of mercury which is shaken vigorously. *Note: can do but not until safe method is found. 4B60.15 hammer on lead Hit a 250 g lead block that has an embedded thermocouple with a heavy hammer and show the temperature rise. A simple air thermoscope is shown. 4B60.16 drop ball on thermocouples A steel ball is dropped onto an anvil holding a set of thermocouples embedded in solder beads. 4B60.20 mechanical equivalent of heat Crank a copper barrel that has copper webbing wrapped around it while under tension and measure the temperature rise of the water inside the barrel. The temperature of a copper barrel filled with water with a copper braid under tension wrapped around it is measured before and after cranking. 4B60.22 motorized mech. eq. of heat Continuous flow apparatus with counter rotating turbines powered by an electric motor. See AJP 28(9),793 4B60.23 Searle's apparatus Searle's apparatus is used to obtain a numerical value of Joule's equivalent. Picture. 4B60.24 mech eq of heat Picture of an elaborate apparatus to measure the mechanical equivalent of heat. Derivation. 4B60.41 heating by bending Pass around a No. 14 iron wire for the students to bend. 4B60.50 bow & stick How to make a fire with a bow and stick. 4B60.55 drill and dowel A motor shaft extended with a hardwood dowel is held against a wood block. Chuck up a dowel in an electric drill and make smoke by drilling the wood block. 4B60.60 flint and steel Sparks from flint and steel or a grindstone show heat from work. 4B60.70 friction cannon Pour ether, alcohol, or water into a tube topped with a cork, and spin by a motor until the frictional heat causes enough vapor pressure to blow the cork. 4B60.75 steam gun Heat a tube until the cork pops off.