Heat in the Environment

Conduction
- Transfer of heat through direct contact between materials.
- Occurs in solids where particles are closely packed.
- Example: A metal spoon getting hot when placed in a pot of boiling water.
Convection
- Transfer of heat through fluids (liquids and gases) due to the movement of the fluid itself.
- Warm fluid rises while cool fluid sinks, creating a circulation flow.
- Example: The warm air rising from a heater and cool air descending.
Radiation
- Transfer of heat in the form of electromagnetic waves, which can occur in a vacuum.
- Does not require a medium for transfer (e.g., can happen through space).
- Example: Heat from the sun reaching the Earth without needing air or any matter in between.

Greenhouse Effect

Caused by greenhouse gases like:
- Carbon dioxide (CO₂)
- Methane (CH₄)
These gases trap heat in Earth’s atmosphere, causing global warming.
NOT caused by the ozone layer.

Insulation

Insulators stop or slow heat transfer (e.g., styrofoam, wool, fiberglass).
Conductors allow heat to pass through easily (e.g., metal).

In homes, insulation helps reduce heat loss and save energy. Additionally, proper insulation can lead to a more comfortable indoor environment by maintaining consistent temperatures throughout the seasons.

Insulation

Insulators stop or slow heat transfer (e.g., styrofoam, wool, fiberglass).
Conductors allow heat to pass through easily (e.g., metal).

In homes, insulation helps reduce heat loss and save energy.

Heated Air

When air is heated, it becomes less dense and rises.

This is an example of convection in action (think of a hot air balloon!).

Radiation
Carbon dioxide
Faster (describes particle movement when heated)
Contraction (shrinking when cooled)
Mantle (part of the Earth responsible for tectonic activity)
Warmer → Cooler (heat always flows this way)
Conduction, Convection, Radiation (the 3 heat transfer methods)

Layers of the Earth (from outside to inside):
1. Crust – Outer rocky layer
2. Mantle – Thickest layer; moves plates with convection currents
3. Outer Core – Liquid metal
4. Inner Core – Solid metal (mostly iron)
Layers of the Atmosphere (from lowest to highest):
1. Troposphere – Weather happens here!
2. Stratosphere – Contains the ozone layer
3. Mesosphere – Where meteors burn up
4. Thermosphere – Hottest layer, northern lights happen here
  
  Why black clothes feel warmer
  - Black absorbs more heat from radiation than light colors.
  - This causes you to feel hotter on a sunny day.
5. How to reduce heat loss in a home (give 2 examples)
  - Add insulation to walls or attics
  - Use weather stripping on windows and doors
  - Close curtains at night
  Thermal expansion in bridges
  - When materials heat up, they expand.
  - Engineers use expansion joints so bridges don’t crack or warp with temperature changes.
6. Reduce your carbon footprint (give 2 ideas)
  - Walk, bike, or use public transportation
  - Use energy-efficient appliances
  - Reduce meat consumption
7. Why some materials feel colder than others
  - Metal feels colder than wood because it is a better conductor.
  - It pulls heat from your hand faster, making it feel colder (even if it’s the same temperature).
  Extra Vocabulary to Know
  - Conductor – allows heat to pass through quickly
  - Insulator – resists heat flow
  - Renewable energy – sources that don’t run out (solar, wind, geothermal)
  - Non-renewable energy – sources that can be used up (oil, gas, coal)
  - Energy efficiency – using less energy to do the same job