1.2.3 Reducing Unwanted Energy Transfers

• What is unwanted energy transfer usually lost as?

  Heat, noise, or friction
• Unwanted energy transfer occurs when energy is converted into forms that are not useful
• Reducing unwanted energy transfers improves overall energy efficiency and sustainability.
• How does energy transfer in conduction?

  Particle collisions
• Convection transfers energy via the movement of fluids
• Radiation can occur in a vacuum.
• What type of thermal insulation reflects radiation?

  Reflective surfaces
• Thermal insulation reduces energy bills by minimizing heat loss
• What is unwanted energy transfer in machines often referred to as?

  Heat, noise, or friction
• Energy transfers primarily through three mechanisms: conduction, convection, and radiation
• What is the medium for heat transfer in conduction?

  Solids
• Which mode of energy transfer does not require a medium?

  Radiation
• Conduction involves heat transfer through fluids.

  False
• Match the type of insulation with its primary mechanism:

  Insulating Materials ↔️ Reduces thermal conductivity

  Trapped Air/Vacuum ↔️ Minimizes convection

  Reflective Surfaces ↔️ Reflects thermal radiation
• Lubricants reduce friction by creating a thin layer between moving parts
• What type of motion is used to reduce friction instead of sliding?

  Rolling
• Streamlining reduces air resistance by creating a smooth, aerodynamic shape.
• Match the sound pollution reduction strategy with its description:

  Noise Barriers ↔️ Blocks sound transmission

  Soundproofing ↔️ Absorbs sound within buildings

  Landscaping ↔️ Absorbs sound and creates buffers
• What are the three primary ways energy transfers?

  Conduction, convection, radiation
• Conduction involves heat transfer through solids
• What medium does convection use to transfer heat?

  Fluids
• Radiation can transfer energy through a vacuum.
• Match the mode of energy transfer with its mechanism:

  Conduction ↔️ Particle collisions

  Convection ↔️ Fluid movement

  Radiation ↔️ Electromagnetic waves
• Conduction transfers heat through particle collisions in solids
• Convection can occur in liquids and gases.
• What type of waves are emitted during radiation?

  Electromagnetic waves
• Steps for using thermal insulation to reduce heat transfer

  1️⃣ Select insulating material

  2️⃣ Apply material to reduce conduction

  3️⃣ Create air gap or vacuum to minimize convection

  4️⃣ Use reflective surfaces to prevent radiation
• Insulating materials reduce heat conduction through low thermal conductivity
• What does a vacuum or trapped air minimize in heat transfer?

  Convection
• Reflective surfaces are used to prevent heat loss by reflecting thermal radiation.
• Match the insulation type with its mechanism:

  Insulating Materials ↔️ Reduces thermal conductivity

  Trapped Air/Vacuum ↔️ Minimizes convection

  Reflective Surfaces ↔️ Reflects thermal radiation
• Friction converts kinetic energy into heat
• How do lubricants reduce friction between moving parts?

  By creating a thin layer
• Steps for reducing friction by replacing sliding with rolling:

  1️⃣ Replace sliding surfaces with wheels or ball bearings

  2️⃣ Ensure surfaces are smooth

  3️⃣ Apply lubricant to reduce rolling friction
• Smoothening surfaces reduces friction by removing irregularities.
• Air resistance opposes the motion of an object moving through air
• What is streamlining used for in reducing air resistance?

  Reducing drag
• Applying smooth coatings to surfaces reduces air resistance.
• Match the technique for minimizing air resistance with its mechanism:

  Streamlining ↔️ Reduces drag with shape

  Surface Treatments ↔️ Smooths surfaces

  Reducing Surface Area ↔️ Decreases perpendicular area
• Noise barriers reduce sound pollution by blocking sound transmission