Thermal properties of matter

• Solids, liquids, and gases expand when they are heated. This is called thermal expansion.
• Rivets are used in shipbuilding and other industries to join metal plates. When the metal plates are heated, the rivets expands. It is then colled and contracts ti bind the plates tightly together.
• A metal lid may get stuck on a glass, so when heated it causes the lid to expand and it can be pulled off easily.
• When gas is heated, its particles move faster Now they push with a greater force on the piston and push it upwards.
• Human body temperature can be measured with a liquid in glass thermometer.
• Liquid in glass thermometer is a thin column of mercury that expands inside the glass tube as it gets hotter.
• A liquid in glass thermometer takes awhile to show an accurate reading because the thermometer was probably stored in a colder environment.
• When a thermometer bulb is at the same temperature as the water, it is in a thermal equilibrium.
• A thermometer tells us about the average energy of the praticles in the object whose temperature we are measuring.
• The temperature of an object is a measure of the average kinetic energy of its particles.
• Internal energy: the total energy of all the particles.
• Temperature: the measure of the average kinetic energy of the individual particles.
• The two fixed points on a thermometer are 0 and 100.
• A liquid in glass thermometer contains mercury which expands at a steady rate when heated. This means that the marks on the scale are evenly spaced. This is called a linear scale.
• The thermometer can be made very sensitive by making the tube which the mercury expands, very narrow. This would cause a small change in temperature to push the mercury a long way up the tube. (makes it possible for small temperature changes).
• A mercury thermometer can have a wide range because mercury is a liquid between -39 and +350 degrees c
• A thermocouple gives an output voltage that depends on the temperature.
• In a thermocouple, a wire of one metal is joined with another one to form 2 junctions.
• One junction in a thermocouple is placed in melting ice and the other is placed in the object that you want to measure a temperature for.
• Thermocouples can be used to measure high temps because they can heat up and cool down very quickly, so they are useful for measuring rapidly changing temps.