3.1a Temperature and Thermal Energy.pdf

Temperature and Thermal Energy Key Vocabulary Terms Temperature Kelvin Celsius Fahrenheit Change of Phase Thermal Energy Lesson Objectives  Understand the scientific meaning of temperature Relate temperatur...

Temperature and Thermal Energy Key Vocabulary Terms Temperature Kelvin Celsius Fahrenheit Change of Phase Thermal Energy Lesson Objectives  Understand the scientific meaning of temperature Relate temperature to kinetic energy Describe Thermal Energy Understand the difference between temperature and thermal energy What are some words used to describe temperature? Temperature  Temperature is often described in terms of how hot or cold something is. Question  What units do we use to measure temperature? Measuring Temperature We often use thermometers to measure temperature. Different thermometers measure in different units called degrees: Degrees Fahrenheit (°F). Degrees Celsius (°C). Degrees Kelvin (°K or K). The Celsius scale is most  commonly used worldwide. Temperature - Definition Scientists define temperature in terms of kinetic energy of particles in matter. Because particles in matter are in motion, they have kinetic  energy. Question Which phase of matter would you hypothesise to have the highest kinetic energy of its particles? Every solid, liquid, and gas is made up of millions of tiny particles that are constantly moving. Solid Liquid Gas Particles move Particles move faster slowly, and vibrate Particles move fast. in place. Particles and move past each The distance are close together. other. Distance between particles is between particles large. increases. Temperature is the average kinetic energy of the particles that make up a material. Review: Answer the Questions in your notebooks 1. 2. 3. 4. 5. The moving particles in matter also have potential energy.  The greater the average distance between particles, the greater the potential energy of the particles. Question  Which phase of matter do you hypothesise to have the lowest potential energy within its particles? Thermal Energy Thermal energy is the sum of the kinetic energy and the  potential energy of the particles that make up a material. Thermal Energy = Kinetic Energy + Potential Energy Lower kinetic energy and lower potential energy Higher kinetic energy and higher potential energy As we increase the thermal energy of objects, particles tend to move faster and further apart.  This is how matter can change phase (or state). Changes in phase occur at specific temperature points for different materials. These are called: Melting points (solid to liquid). Boiling points (liquid to gas). Question What do scientists call the temperature at which a solid becomes a liquid? Phase Change Terms