Physical Science Notes
Unit 2 Lesson 3
The kinetic theory of matter explains that matter is made up of particles, which are in constant motion resulting in the different states of matter.
Matter is made of constantly moving particles, which tells us how the matter in solids, liquids, and gases behaves. When molecules bump into each other, they do not gain or lose energy, they only transfer it, so there is no net energy change (law of the conservation of energy).
In a solid, molecules vibrate in a fixed position and do not move around.
In a liquid, those molecules vibrate and move freely and faster throughout the liquid, taking on the shape of the container.
In a gas, the molecules move completely at random and at very high speeds and spread to the limit of the container.
Unit 2 Lesson 8
When you study thermodynamics, you study the movement of energy.
Energy comes in lots of different forms, such as heat energy, chemical energy, light energy, and electrical energy. The three laws of thermodynamics tell us about the movement of heat.
The first law is a statement of the conservation of energy: The total amount of energy and matter in the universe remains constant.
The second law says that if a system sits without any energy going into or coming out of it, over time its potential energy will be less than it was when it started. The entropy (amount of disorder in a system) of the universe is increasing.
The third law is a statement about reaching absolute zero (0 K). If the third law were to actually be demonstrated in nature, the entropy of a system would be zero.
Unit 2 Lesson 9
Heat energy is measured in calories, increases with the speed of molecules, and is required for a phase change to occur.
Heat energy is measured in calories and is required to increase the speed of molecules, which is measured as temperature. But some heat is also required for phase change. So as you heat something, the energy is used to raise the temperature until phase change occurs. At
The kinetic theory of matter explains that matter is made up of particles, which are in constant motion resulting in the different states of matter.
Matter is made of constantly moving particles, which tells us how the matter in solids, liquids, and gases behaves. When molecules bump into each other, they do not gain or lose energy, they only transfer it, so there is no net energy change (law of the conservation of energy).
In a solid, molecules vibrate in a fixed position and do not move around.
In a liquid, those molecules vibrate and move freely and faster throughout the liquid, taking on the shape of the container.
In a gas, the molecules move completely at random and at very high speeds and spread to the limit of the container.
Unit 2 Lesson 8
When you study thermodynamics, you study the movement of energy.
Energy comes in lots of different forms, such as heat energy, chemical energy, light energy, and electrical energy. The three laws of thermodynamics tell us about the movement of heat.
The first law is a statement of the conservation of energy: The total amount of energy and matter in the universe remains constant.
The second law says that if a system sits without any energy going into or coming out of it, over time its potential energy will be less than it was when it started. The entropy (amount of disorder in a system) of the universe is increasing.
The third law is a statement about reaching absolute zero (0 K). If the third law were to actually be demonstrated in nature, the entropy of a system would be zero.
Unit 2 Lesson 9
Heat energy is measured in calories, increases with the speed of molecules, and is required for a phase change to occur.
Heat energy is measured in calories and is required to increase the speed of molecules, which is measured as temperature. But some heat is also required for phase change. So as you heat something, the energy is used to raise the temperature until phase change occurs. At