Thermodynamics
Thermodynamics
Thermal Properties of Matter
Thermometers
PIRA: 4A10.10
Description: Show the varying types of thermometers and describe what each is used for.
Linear Expansion Apparatus
PIRA: 4A30.05
Description: As a rod is heated, it deflects the needle showing expansion.
Bimetal Strip
PIRA: 4A30.10
Description: A bimetal strip is manufactured by pressing together two metals of different thermal expansion coefficients. When the strip is heated, it bends one direction and when cooled it bends in the opposing direction.
Ball & Ring
PIRA: 4A30.21
Description: When the ball and ring are both at the same temperature the ball will just barely fit through the ring. If the ball is heated up or the hoop is cooled (in liquid nitrogen) the ball will not fit through the ring. There is also a bar and slot that works using the same principle. For heating, we use either boiling water or a Bernzomatic torch and liquid nitrogen for cooling.
Pin Breaker
PIRA: 4A30.31
Description: Heat a rod to expansion and it breaks a 1/8″ diameter pin as it cools.
Wire Heater
PIRA: 4A30.61
Description: A wire is put under tension by a small spring. The apparatus is viewable on the overhead projector. When the wire is heated by an electrical current, it stretches and the coils of the spring contract.
Lead Bell & Solder Spring
PIRA: 4A40.10
Description: A bell made of lead will ring when cooled to the temperature of liquid nitrogen. The coil of solder will perform like a spring when cooled to – 176 degrees C.
Smashing Rose, Rubber Tubing, or Racquet Ball
PIRA: 4A40.30
Description: When these objects are cooled to the temperature of liquid nitrogen, they will shatter like glass.
Heat and the First Law
Specific Heat Apparatus
PIRA: 4B10.30
Description: Four metal cylinders {lead, iron, aluminum, and copper} of the same diameter and mass are heated to the temperature of boiling water in a beaker. The cylinders are then placed on a wax block and allowed to melt into the block. The distance that they melt into the block is a measure of their specific heat capacity.
Convection Tube
PIRA: 4B20.10
Description: A rectangular tube filled with water. A small amount of potassium permanganate is added to the water for color. When the tube is heated, the current flow is quite visual.
Melting Parafin (conduction)
PIRA: 4B30.12
Description: Six rods of different metals are attached to a center ring which can be heated with a Bunsen burner. Wax squares are placed at the midpoint and the end of each rod. When enough heat has reached the squares of wax, they melt and fall off. The conduction difference between the metals is quite apparent.
Light the Candle
PIRA: 4B40.10
Description: Two parabolic mirrors are placed on the table. One has a heating coil at its focal point and the other has a candle and match at the focal point. When the heating coil is on, there is enough radiated heat to light the match and candle.
Radiometer
PIRA: 4B40.61
Description: When exposed to light {IR is best} , the vanes spin very rapidly due to radiated thermal energy.
Boy Scout Fire Maker
PIRA: 4B60.55
Description: A bow for starting fires “Indian style”. It uses friction to generate heat.
Dowel Drill
PIRA: 4B60.56
Description: A dowel is put in the chuck of the drill and it will burn a hole in a soft piece of wood.
Change of State
PV diagram model
PIRA: 4C10.10
Description: Pressure vs. volume 3D models for H2O and CO2.
Melting Ice
PIRA: 4C20.05
Description: The objective of this demonstration is to introduce critical temperatures.
A small portion of water is frozen with a thermometer in it. The computer is set up to take readings from the thermometer in specified intervals and graph the results.
Begin the computer program before turning on the hot plate, then turn on the hot plate. The computer will graph the temperature of the water. The graph will exhibit two flat spots. These are critical temperatures where a phase change is taking place.
Cryophorus
PIRA: 4C31.10
Description: A small amount of water is enclosed in an evacuated vessel. The vessel is two bulbs connected by a tube. One bulb has a concave surface to hold a small amount of liquid nitrogen. When the liquid nitrogen is poured into the concave surface, the water in the opposite end of the vessel will begin to freeze.
Drinking Bird
PIRA: 4C31.30
Description: The bird shows that work can be extracted from a low thermal energy pool through evaporation.
Pulse Glass
PIRA: 4C33.50
Description: There are two pulse glasses available, one large and one small. When the end with the liquid is placed in the palm of the hand, the liquid is forced into the other end due to vapor pressure.
Crush the Can (Steam)
PIRA: 4C33.60
Description: A small amount of water is heated and the can is capped, the can is then placed in ice water. Because steam molecules are active, when they are cooled they condense crushing the can.
Kinetic Theory
Crookes’ Radiometer
PIRA: 4D20.10
Description: A pinwheel inside of a glass bulb with partial vacuum rotates due to radiation pressure. Particularly helpful with infrared.
Cenco Kinetic Theory Apparatus
PIRA: 4D30.10
Description: A motor driven device, which can be placed on the overhead to show a simulation of molecular motion. It contains many small ball bearings of the same size but it could be filled with ball bearings of different sizes. Temperature change simulation can be achieved by controlling the speed of the motor.
Absolute Pressure Gauge
PIRA: 4D30.25
Description: The absolute pressure gauge is used to determine the pressure of gas at different known temperatures. The points normally used are: boiling water, ice water, and liquid nitrogen. Used to determine absolute zero. An overhead transparency graph of temperature vs. pressure can be used. The absolute pressure gauge is used to determine the pressure of a gas at different known temperatures. The points normally used are: boiling water (100°C), ice water (0°C), and liquid nitrogen (-196°C). The pressure is recorded on an overhead transparency graph for each of the temperatures. A best-fit line drawn through the three points to the pressure axis will determine absolute zero (approximately).
Diffusion in Air (Smell of Paint Reducer)
PIRA: 4D50.11
Description: The paint reducer is a strong smelling chemical that diffuses through the air when the container is opened so that everyone will be able to smell it.
Diffusion in Liquid (Food Color in Water)
PIRA: 4D50.61
Description: A couple drops of food coloring diffuses through water.
Gas Law
Galileo’s Thermometer
PIRA: 4E10.12
Description: A spherical flask is inverted and connected to a thin tube which is inserted in a beaker of water. The water is colored for easy visibility. When the air in the flask is heated with a torch, it expands and push the fluid down the tube. If heated sufficiently, gas will escape from the bottom of the tube and when the air cools to room temperature, the fluid in the tube will rise above the level of the beaker (this should be done as prep.). When the flask is cooled with a wet towel, the fluid level in the tube will rise.
Balloons in Liquid Nitrogen
PIRA: 4E10.20
Description: Pour liquid nitrogen over an air filled balloon until it collapses and then let it warm up again.
Entropy and the Second Law
Unmixer
PIRA: 4F10.11
Description: A tall cylinder filled with glycerol. If a small amount of dye can be injected into the glycerol, a crank on the cylinder can be turned and an inner cylinder spins and spreads out the dye {mixes it}. When the crank is turned the opposite direction, the dye is returned to its original position. Thus, the unmixer.
Dust Explosion
PIRA: 4F10.40
Description: An explosion due to organic dust can be caused using lycopodium powder. A lit candle is placed in a can. Then, a spoon of lycopodium powder is placed where it can be dispersed with a puff of air.
Stirling Engine
PIRA: 4F30.10
Description: This demonstrates that the Sterling cycle can be used to perform work. The Stirling Engine consists of a cold reservoir (filled with crushed ice), hot reservoir (produced by burning gas), and a chamber of air. Two pistons one from the hot reservoir and one from the cold reservoir are connected to a flywheel and are 90° out of phase. The configuration allows for the trapped air in the chamber to be compressed and expanded. Once the heat reservoir becomes hot enough, the flywheel can be spun and it will continue to spin until the two reservoirs arrive at temperatures nearer equilibrium.
Ice Mobile
PIRA: 4F30.61
Description: A pulley system similar to a compound bow has nitinol wire (“memory wire”) around it. Half of the set up is placed in hot water and an ice cube is placed against the wire between the two pulleys. The pulleys then begin to spin because of the differences in temperature, creating an Ice Engine.
Thermoelectric Fan
PIRA: 4F30.62
Description: A fan has one blade placed in hot water and the other in cold. The difference in temperature will cause the fan to spin.