1. 10.1 Temperature, Thermal Energy, and Heat
The kinetic molecular theory explains that all matter is made up of tiny particles.
These atoms and molecules are constantly in motion.
Kinetic energy is energy due to motion.
Solids, liquids, and gases behave differently according to the kinetic molecular theory.
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2. 10.1 Temperature, Thermal Energy, and Heat
The particles of a substance move differently for different states.
In solids, particles vibrate slightly but do not change position.
In liquids, particles vibrate more and move around within a set volume.
In gases, particles vibrate greatly and move around to take all volume available.
Solids, liquids, and gases behave differently according to the kinetic molecular theory.
See page 424
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3. The movement of particles is what we measure as temperature.
Temperature is the measure of the average kinetic energy of all particles in a sample
A cup of tea feels hot because average kinetic energy of all its particles is more than your hand
As the particles’ average kinetic energy increases, the temperature of a sold, liquid, or gas will also increase.
Particles in a glass of cold water move slower and have less kinetic energy than particles in a cup of hot water
Measured in degrees Fahrenheit (°F), degrees Celsius (°F), or Kelvin (K). scale.
Celsius scale ws named after Swedish astronormer Anders Celsius ( ). First used in used around the world. Based on two fixed points: freezing point of water (0C) and BP.
1848 William Thompson of Scotland proposed temp scale bases on absolute zero, temp at which particles have no kinetic energy.
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4. Since temperature is a way of measuring the average energy of the particles in an object, it does not change when the size of the object changes.
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5. Thermal energy = all kinetic energy + all potential energy
Thermal energy is the total energy of all the particles in a substance.
Thermal energy = all kinetic energy + all potential energy
KE is the energy of movement.
PE is the stored energy due to its position or state
= how much the particles vibrate, and
therefore how much space they take up.
Kinetic ( greek kinetikos – to put in motion)
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7. Thermal Energy
The amount of thermal energy depends on the size of the object - the larger the object, the more moving particles it contains.
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8. Heat
Heat is the amount thermal energy that transfers from an area of higher temperature to an area of lower temperature.
Ex. When you cup your cold hands around a mug of hot chocolate, heat is transferred from the mug to your hands.
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9. Thermal Energy Transfer
Conduction is the transfer of heat by direct contact.
Heat is transferred from higher temperature, (higher kinetic energy), to lower temperature, where particles have lower kinetic energy.
For example, a cold spoon warms when placed in a cup of hot coffee.
Thermal conductors transfer heat easily, while insulators do not.
See pages
Take the Section 10.1 Quiz
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10. Thermal Energy Transfer
Convection is the transfer of heat in fluids (liquids and gases).
Convection is the movement of heat from hot to cold within a fluid, or the movement of hot liquid to an area of cold liquid.
Because there is a density difference, hot fluid (low density) moves to cold.
This is how convection currents form.
See pages
Take the Section 10.1 Quiz
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11. Thermal Energy Transfer
Radiation is the transfer of radiant energy by waves through space.
What we feel as heat is generally called infrared radiation.
Earth’s interior thermal energy comes from the core, plus
some radioactive element decay .
See pages
Take the Section 10.1 Quiz
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12. Electromagnetic Radiation (EMR) – radiates outward in all directions.
Anything with temperature more than absolute zero radiates heat. The heat is transferred when material absorbs radiation (which increases temperature or causes a substance to melt or evaporate).
Electromagnetic Radiation (EMR) – radiates outward in all directions.
Infrared (IR) - feel heat when sitting next to a campfire
Visible light
Solar Radiation – visible, IR and other.
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15. Check your Understanding Checking Concepts 1-5 p 435
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