Conservation of energy

• What is the conservation of energy principle?

  Energy can be transferred, stored, or dissipated
• What does it mean that energy can never be created or destroyed?

  Energy only moves between objects and forms
• How does charging a phone illustrate the conservation of energy principle?

  Electrical energy converts to chemical energy
• What happens to chemical energy when you use your phone?

  It converts back to electrical energy
• What type of energy conversion occurs in the phone's screen?

  Electrical energy to light energy
• What type of energy conversion occurs in the phone's speaker?

  Electrical energy to sound energy
• What is meant by wasted energy?

  Energy transferred to unintended forms
• What is the common form of wasted energy when using a phone?

  Heat energy
• What defines an open system in physics?

  Energy and matter can move freely
• In the phone example, what is considered the environment?

  Everything outside the phone
• What happens to heat energy when the phone is in a sealed jar?

  It dissipates to the air inside the jar
• How does a closed system differ from an open system?

  Energy and matter cannot enter or escape
• What does it mean for the overall energy of a closed system?

  It doesn't ever change
• What are the key concepts of the conservation of energy principle?

  • Energy can be transferred, stored, or dissipated
  • Energy cannot be created or destroyed
  • Energy moves between different objects and forms
• What are the energy transformations when charging and using a phone?

  1. Charging: Electrical energy → Chemical energy
  2. Using: Chemical energy → Electrical energy
  3. Screen: Electrical energy → Light energy
  4. Speaker: Electrical energy → Sound energy
• What distinguishes open systems from closed systems?

  • Open System: Energy and matter can move freely
  • Closed System: Energy and matter cannot enter or escape
• What is wasted energy and its common form in devices?

  • Wasted energy: Energy transferred to unintended forms
  • Common form: Heat energy