Change of State

PIRA classification 4C

Table of Thermodynamics

Thermodynamics (4B): Heat and the First Law

Thermodynamics (4D): Kinetic Theory

Lecture Demonstrations

4C10. PVT Surfaces

PIRA #	Demonstration Name	Subsets	Abstract
4C10.10	PVT surfaces		Three dimensional models of PVT curves are shown for different substances.
4C10.10	thermodynamic surfaces		Models of two thermodynamical surfaces.
4C10.11	thermodynamic surfaces		Pictures of p-v-T,f-p-T, and delta F-S-r surfaces in a heavy duty article. See AJP 30(12),870

4C20. Phase Changes: Liquid-Solid

PIRA #	Demonstration Name	Subsets	Abstract
4C20.10	supercooled water		A small test tube of water is cooled in a peltier device and the temperature is followed with a thermocouple.
4C20.11	supercooling water		Water in a small test tube is cooled to -4 C by placing in a dry ice/alcohol bath. Shake to freeze and the temperature will rise to 0 C.
4C20.12	drop freezer		1971 Apparatus Competition Winner. Drops are placed on a copper plate with a tail in dry ice. A thermometer is placed in the copper plate and a mirror at 45 degrees allows easy observation of the drops. See AJP 39(10),1125
4C20.15	supercooling in four substances		Four methods are given for supercooling various substances.
4C20.21	ice bomb in liquid nitrogen		An ice bomb is placed in a beaker of liquid nitrogen in a plexiglass cage.
4C20.22	expansion of freezing bismuth		A hummock rises on the surface of bismuth as it freezes in a tube.
4C20.23	contraction of paraffin		Let a beaker of liquid paraffin freeze.
4C20.30	regelation		Cut through a block of ice with a wire loop that has a heavy mass hanging from it. Copper cuts through faster than iron or thread. A copper wire under tension cuts through a block of ice. A mass hanging from a loop of thin stainless steel wire cuts through a block of ice.
4C20.31	regelation		Explanation of regelation. Copper cuts through faster than iron or thread. See TPT 3(4),186
4C20.32	crushed ice squeeze		Substances that expand on freezing show a lowering melting point under pressure. Two blocks of ice, held together by hand, will freeze. Crushed ice squeezed in a thick walled cylinder forms a solid block. Also complete directions for the standard demo.
4C20.35	liquifying CO2		Press down on a piston on dry ice in a clear tube until at 5 atmospheres liquification occurs. A strong bulb with a 1 cm square neck area is filled with dry ice and a 5 kg mass is added. The melting point of CO2 is about 5 atmospheres. Lift the weight slightly to freeze.
4C20.36	CO2 syringe		Put some CO2 in a small transparent syringe and squeeze to liquefy. Can be shown on the OH. See AJP 47(3),287
4C20.40	freezing liquid nitrogen		Put some liquid nitrogen in a clear dewar and pump until it freezes. Pumping on liquid air will produce solid nitrogen at -210 C. Air passed slowly over the outside of the flask will condense out liquid air at atmosphere pressure. In addition to the standard freezing by evaporation in a clear dewar – pop off the cork when the nitrogen is solid and it will instantly turn to liquid while the temperature remains below its boiling point.
4C20.42	freezing nitrogen modification		The dewar has a smaller cross section in the lower part to prevent the frozen plug from rising to the pumping port. See AJP 36(9),919
4C20.45	CO2 expansion cooling		Shoot off a fire extinguisher at a test tube of water, freezing the water.
4C20.46	CO2 cylinder		Liquid CO2 from cylinder is released into a heavy bag, freezing the central stream by evaporative cooling.
4C20.50	heat of fusion of water		Melt ice in a beaker of water and measure the temperature.
4C20.51	heat of fusion of ice		Melt some ice in a calorimeter with a known amount of water.
4C20.52	freezing lead		Insert thermocouple into molten lead and plot the temperature on an x-y recorder as it freezes.
4C20.53	freezing tin		Tin is heated to 360 C and temperature readings taken every 30 seconds until the temperature reaches 160 C. Half the time the temperature remains at 230 C.
4C20.54	heat of fusion of water		Place a thermocouple cooled in liquid nitrogen in warm water. Plot temperature as ice forms and then melts.
4C20.55	heat of solution		A manometer shows cooling when hypo or ammonium chloride are added to water, heating when sulfuric acid is used. ALSO – equal weights of water and ammonium nitrate will lead to freezing. Heat is generated if sulfuric acid is dissolved in water. Cooling results if hypo or ammonium nitrate is dissolved.
4C20.59	latent heat heating		Two experiments that use the latent heat from one substance freezing to heat another.
4C20.60	heat of crystallization		Prepare a supersaturated solution of sodium acetate or sodium sulfate and drop in a crystal to trigger crystallization. A thermocouple will show the change in temperature.
4C20.61	heat of crystallization		A manometer hooked into the jacket of a double walled flask is used to detect the change in temperature of a sodium thiosulfate solution as it crystallizes.
4C20.62	heat of crystallization		A manometer indicates heating when a flask of supercooled hypo solution crystallizes.
4C20.70	project crystallization		Project while crystallization occurs in a thin film of melted sulfur or saturated solution of ammonium chloride.
4C20.71	crystallization		Crystallization from a conc. solution of sodium acetate or sodium hyposulfate. See also E-195 (lead tree) and L-122 (polarization).
4C20.72	water crystals in soap film		A ring with a soap film is cooled in a chamber surrounded by dry ice on the overhead projector. Water crystals form.
4C20.73	crystal growth on the overhead		Various organic compounds are used to show crystal growth between crossed Polaroids on the overhead projector. Tartaric acid and benzoic acid are melted together and the crystal growth on cooling is observed between crossed Polaroids on the overhead projector.
4C20.80	Liquid Nitrogen Ice Cream		Physics fun with Liquid Nitrogen. Discuss the phase change and crystallization when cooling down liquid ice cream mixture into tasty ice cream with Liquid Nitrogen.
4C20.90	hard sphere model		A two dimensional hard sphere model of a fluid shows propagating holes or flow if 4% of the spheres are removed. See AJP 45(4),395
4C20.98	Metglas 2826		Metglas 2826 is a metal that has been quenched from liquid to solid without crystallization. The mechanical, electrical, and magnetic properties are demonstrated. See AJP 46(1),80
4C20.99	Wood’s metal		The recipe for Wood’s metal (melting point 65.5 C).

4C30. Phase Changes: Liquid-Gas

PIRA #	Demonstration Name	Subsets	Abstract
4C30.10	boiling by cooling	pira200	Boil water vigorously in a flask, stopper and remove from heat, cool with ice or water to show boiling at reduced pressure. OPTIONAL: A thermometer or thermocouple can be added to show temperature.
4C30.15	boiling at reduced pressure		A thermometer measures the boiling point as a vacuum pump is used to reduce the pressure in a flask of water. Pump on a flask of warm water with aspirator or vacuum pump until boiling starts. See TPT 2(4),178
4C30.20	superheating liquids		Water is superheated in a very clean flask free of flaws. A similar flask with boiling water is nearby. Add chalk dust to the superheated water and boiling starts explosively.
4C30.21	bumping		When an open tube (H-82) containing water is heated the temp will rise above 100 C and before a vapor bubble suddenly forms.
4C30.25	geyser		A conical tube 12 cm at the bottom and 4 cm at the top, 2 m long, and heated at the bottom, models a geyser.
4C30.27	steam bomb		Heat a corked test tube or make a bomb by sealing off some water in a glass tube and heating it. Flying glass hazard.
4C30.30	helium and CO2 balloons in liquid N2		Helium and CO2 balloons are immersed in liquid nitrogen. Cut open the CO2 balloon to show solid carbon dioxide.
4C30.33	ice stove		Boil away liquid air in a teakettle on a cake of ice. (Jerry’s Teakettle?)
4C30.35	burst a balloon		A small amount of liquid air in a test tube blows up a balloon until it bursts. (800:1 volume ratio). Pour some liquid nitrogen in a small flask and cap with a balloon.
4C30.36	Liquid Nitrogen Cannon		A stainless steel cup containing about 2 tablespoons of Liquid Nitrogen is placed into the nitrogen cannon. A cork is then pounded into the cannon to hold in the nitrogen gas. Finally, the liquid nitrogen builds up enough energy in the cannon to shoot a cork across the room. For faster action tip the cannon on its side to pour out the LN2 from it’s cup.
4C30.38	LN2 Soda Bottle Bomb		Liquid Nitrogen is sealed in a two-liter soda bottle and is placed in a special holder under a industrial trash can for safety.
4C30.40	heat of vaporization of water		Boil water in a beaker while measuring the temperature.
4C30.50	bromine cryophorous		One end of an L-shaped evacuated tube containing bromine is immersed in a dry ice/alcohol mixture.
4C30.51	bromine condensation		The color of bromine gas in one end of a tube is reduced when the other end is cooled.
4C30.55	gas and vapor under compression		A mercury piston applies equal pressure to air and sulfur dioxide until the SO2 collapses into liquid at 2 1/2 atmospheres.
4C30.60	steam into calorimeter		Pass steam into a calorimeter to determine the heat of condensation.
4C30.80	making liquid oxygen		Liquid oxygen will drip from the outer surface of a thin copper cone filled with liquid nitrogen.
4C30.81	heat exchanger oxygen liquifier		A heat exchanger is used to liquefy oxygen from a high pressure tank. Picture, Construction details in appendix, p. 1297.
4C30.82	liquification of air under pressure		A bicycle pump is used to put a test tube immersed in liquid air under pressure. Liquification will continue as long as the tube is operated.

4C31. Cooling by Evaporation

PIRA #	Demonstration Name	Subsets	Abstract
4C31.10	cryophorous		One end of an evacuated glass tube with bulbs at each end is put in liquid nitrogen, water in the other end will freeze. One end of a tube is stuck in a cold trap and water in the other end freezes.Water in one end of an evacuated J tube will freeze when the other is placed in a ice-salt mixture, alcohol-dry ice mixture, or liquid air.
4C31.10	cryophorus		Place a cryophorus in liquid nitrogen.
4C31.11	cryophorous		Water in an evacuated sealed flask with a concave bottom freezes when it is inverted and a dry ice/alcohol mixture is placed in the concavity.
4C31.12	cryophorous		A Lucite assembly for the overhead projector with an evacuated chamber holding water and an area for a dry ice/acetone mixture.
4C31.20	freezing by evaporation		For the overhead projector: make a hole for a small thermometer in the bottom of a small test tube and pump on a small amount of water. Pump down some distilled water in a chamber until the water freezes. Crossed Polaroids make the effect more visible. See AJP 35(9),x
4C31.21	freezing by evaporation		Freeze water in a watch glass over a dish of sulfuric acid in a bell jar.
4C31.22	Freezing_by_Evaporation		Freeze water in a flask by pumping through a sulfuric acid trap. Supercooling up to 10 C is possible.
4C31.30a	Drinking Bird	pira200	The drinking bird has a wet head which evaporates drawing liquid up his neck and tipping him over. Cooling causes vapor to condense, lowering the center of gravity until the bird tips, raising the c. of g.
4C31.30b	Tippy Sprott		A supper sized version of the drinking bird, but this one is made to look like Prof. Clint Sprott. Watch the wet head, with the aid of a heat lamp, draw liquid up his neck and tipping him over. Cooling causes vapor to condense, lowering the center of gravity until the bird tips, raising the c. of g.
4C31.31	CO2 cartridge cools		Puncture a CO2 cartridge and the steel bulb will cool enough to form frost but there is not enough gas to produce snow.
4C31.32	evaporating carbon disulfide		Evaporating carbon disulfide (highly inflammable and poisonous) is used to form frost.
4C31.33	evaporating ether		Evaporating ether in a watch glass freezes a drop of water between the bottom of the glass and a cork. A method for burning off the ether is shown. Diagram.
4C31.34	evaporating ethyl chloride		Ethyl chloride is used to freeze water in a small dish or cool a thermometer.
4C31.35	cooling by evaporation		An attached manometer shows cooling when several drops of ether are placed in a flask.
4C31.37	pulse-glass engine		A pulse glass will oscillate when mounted in a stirrup so one side and then the other can contact a cool pad.

4C32. Dew Point and Humidity

PIRA #	Demonstration Name	Subsets	Abstract
4C32.10	sling psychrometer		Use a commercial sling psychrometer to determine relative humidity. Two thermometers, one with a wet wick, are mounted on a device swung around the head.
4C32.11	wet and dry bulb		Wet and dry bulb thermometers are mounted on a frame with a humidity graph. Wet and Dry bulb readings.
4C32.15	dial hygrometer		A dial type hygrometer is pictured.
4C32.16	demonstration hair hygrometer		A hair is connected to a pivot.
4C32.20	dew point measurement		Evaporating alcohol cools a shiny surface until dew forms.
4C32.21	dew point		Evaporating ether cools a gold band until dew forms.
4C32.22	dew point		Reflect a light beam off two bright plates, one cooled by ether.
4C32.23	dew point with evaporating ether		When the dew point is reached in a test tube of evaporating ether, water drops on the outside complete an electrical circuit, lighting a neon lamp.
4C32.24	condensation and coalescence		Watch the shiny surface of a frigister as small water drops grow and coalesce.
4C32.40	condensation nuclei		Cigar smoke is introduced into a steam jet.
4C32.41	condensation nuclei		An extinguished match is held in the steam from a tea kettle.
4C32.50	fog in a bell jar		Place moistened cotton in a bell jar and evacuate until fog forms. After cleaning the air of dust, ions are introduced and a thick fog forms.

4C33. Vapor Pressure

PIRA #	Demonstration Name	Subsets	Abstract
4C33.10	vapor pressure in barometer		Place four mercury barometers in a line and introduce different volatile liquids into each including alcohol and water to show vapor pressure.
4C33.11	vapor pressure with a manometer		Three flasks containing water, alcohol, and ether are connected by stopcocks to the evacuated side of a mercury manometer.
4C33.12	vapor pressure of water		A barometer is sealed off with liquid over the mercury.
4C33.13	comparison of vapor and gas		Barometer tubes are moved up and down in a deep well of mercury. One contains air, the other alcohol vapor. The mercury level remains the same in the tube with alcohol vapor.
4C33.13	vapor pressure tube		Separate tubes are made up with a liquid sealed over mercury and with an evacuated tube extending out of the mercury to show the vapor pressure.
4C33.20	addition of vapor pressures
4C33.20	addition of vapor pressures		Add water and then alcohol to a mercury barometer
4C33.21	addition of partial pressures		Measure the pressure change with a manometer when a vial of ether is broken in a flask of air.
4C33.25	soda pop pressure		Attach a pressure gauge to a soda pop bottle and measure the buildup of pressure.
4C33.30	vapor pressure curve for water
4C33.30	vapor curve of water		Boil water in a flask attached to one side of a mercury manometer, remove the heat and seal off the flask from the atmosphere, take readings of the temp and pressure difference as the system cools. See AJP 29(10),xiii
4C33.30	vapor pressure curve for water		A flask of boiling water is stoppered with a thermometer and mercury manometer. Readings are taken as the water cools.
4C33.31	vapor pressure of water vs temp		Add a thermometer and pressure gauge to a pressure cooker the demonstrate the effect of temperature on partial pressure of water.
4C33.32	vapor pressure of water at boiling		Insert a mercury filled J tube with water at the closed end into a boiling water bath and the mercury comes to the same level on both sides of the tube.
4C33.33	vacuum by freezing		A table of vapor pressure values for water at standard bath temperatures down to -90 C. Some demo suggestions are included.
4C33.35	vapor pressure curve for CCl4		Modification of a flexible tube manometer to measure the vapor pressure curve of CCl4.
4C33.50	pulse glass
4C33.50	pulse glass		A tube with a small bulb on each end partially filled with a volatile liquid is held by one bulb in the palm forcing the liquid into the other bulb.
4C33.50	pulse glass		Just a picture.
4C33.55	vapor pressure fountain		Ether is introduced into a stoppered flask half full of water with a nozzle extending to near the bottom of the flask. The vapor pressure forces the water out the nozzle. Diagram.
4C33.56	addition of vapor press. with ether		An apparatus is constructed of glass tubing to allow one to add ether to entrapped air at atmospheric pressure and measure the increased pressure. Reference: AJP 13(1),50.
4C33.57	flask inverted over ether		When a flask is inverted over ether, bubbles form due to the partial pressure of ether.
4C33.58	retarded evaporation		Introduce a volatile liquid into two flasks connected to mercury manometers, one evacuated and the other full of air. The final pressure is the same but the time to get there differs.
4C33.60	beakers in a bell jar		Beakers of water and brine are placed in a bell jar and left for weeks. The brine gains water.
4C33.61	lowering of v.p. by dissolved salt		A manometer separates water and a salt solution in a closed system.
4C33.62	vapor pressure of solutions		Aqueous solutions of salt or sugar have a higher boiling point than water.

4C40. Sublimation

PIRA #	Demonstration Name	Subsets	Abstract
4C40.00	Sublimation
4C40.10	sublimation of carbon dioxide
4C40.10	carbon dioxide		Watch carbon dioxide sublimate.
4C40.10	carbon dioxide		Evaporation of “dry ice”.
4C40.10	sublimation of CO2		Small solid carbon dioxide flakes are generated by cooling a CO2 balloon in liquid nitrogen.
4C40.11	carbon dioxide		Show chattering due to formation and escape of vapor.
4C40.12	carbon dioxide rocker		Detect the evaporation of gas by the high pitched rocking motion of one end of an iron rod placed on “dry ice”.
4C40.15	blow up balloon with CO2
4C40.15	blow up a balloon with CO2		Attach a balloon to a test tube with dry ice and when the balloon is inflated immerse the tube in liquid air.
4C40.16	change of volume with change of stat		Dry ice blows up a balloon.
4C40.20	iodine		Place melted iodine crystals in a partially evacuated tube and heat.
4C40.30	ammonium chloride		Heat ammonium chloride in a test tube and it evaporates without melting, coating the cool sides of the tube. ALSO- solidify CO2.
4C40.40	camphor		Heat camphor in one end of a tube and the vapors will condense on the cooler end. Project.
4C40.50	sublimation of ice and snow		Freeze water in a large dish, then cover portions with rectangles of aluminum foil. After three weeks, the uncovered areas have sublimed about a half inch.

4C45. Phase Changes: Solid – Solid

PIRA #	Demonstration Name	Subsets	Abstract
4C45.00	Phase Changes: Solid – Solid
4C45.10	phase change in iron
4C45.10	phase change in iron
4C45.10	phase change in iron		A long iron wire heated to 1000 K will sag as it goes through a phase change.
4C45.20	solid-solid phase projection		The salt ammonium nitrate exhibits five phase transitions between 169 C and -16C. Heat the salt on a microscope slide with an electrically conducting coating on one side.
4C45.30	polymorphism
4C45.31	polymorphism		Mercury iodide changes from red to yellow at 126 C. Ammonium nitrate has five solid phases at -16, 35, 83, 125 C – best demonstrated between crossed Polaroids on the overhead projector.
4C45.35	phase transitions – magnetic model		A magnetic model demonstrates phase transitions and excitations in molecular crystals. Construction details and hints included along with theory.

4C50. Critical Point

PIRA #	Demonstration Name	Subsets	Abstract
4C50.00	Critical Point
4C50.10	critical point of CO2
4C50.10	critical point of CO2		The meniscus in a tube containing liquid CO2 at high pressure disappears when warmed.
4C50.10	critical point of carbon dioxide		Gently heat a glass tube containing liquid CO2. The critical point is 73 atmospheres and 31.6 C.
4C50.10	critical point of CO2		Liquid CO2 in a heavy wall glass tube is heated to show disappearance of the meniscus.
4C50.10	CO2 critical point		Warm a tube containing liquid CO2. The critical point is 73 atmospheres at 31.6 C.
4C50.11	critical point of CO2		Tubes filled with liquid CO2 at, above, and below the critical point are prepared to demonstrate behavior of a non-ideal gas. Tube preparation instructions.
4C50.15	citical state analog		Use the critical solution of aniline and cyclohexane as an analog of the critical state.
4C50.20	critical opalescence
4C50.20	critical opalscence		A sealed chamber containing freon is heated to the critical point.
4C50.30	critical temp of ethyl chloride		Directions for making an ethyl chloride apparatus (187.2 C, 52 atmos).
4C50.40	Triple_Point_of_Water		A sealed Erlenmeyer flask filled with ice water has the air pumped out of it creating a partial vacuum. Thus brings the mixture to the triple point of water whereupon the mixture boils showing solid, liquid, and gas existing at the same pressure and temperature.