1. heat

2. Heat and the water cycle

3. Heat and the water cycle
The Sun – provides radiant energy to warm the air and water
Vaporization (Evaporation) – liquid water changes state as it absorbs heat (warm air containing moisture rises)
Transpiration – plants release water as vapour
Condensation – moisture in cooling air condenses around dust particles forming clouds
Precipitation – water falls back to earth as a liquid in warmer air (rain) or solid in colder air (hail/sleet/snow)
Surface Run Off - water returns to larger bodies (streams, lakes, oceans, seas)
Groundwater – plants absorb water through soil

4. HEATing homes Heating a Single Room: Air = good heat insulator
= poor heat
conductor
To heat air in a
room, a
convection
current is needed
ex) Using an
electric heater

5. HEATing homes Hot Water Heating Systems: Some homes and buildings use
hot water to provide heat
ex) radiator system

6. Lack of exposure to sunlight
Wasting heat
Source of Heat Loss
Remedies
Walls and roof
Increase the amount of insulation in the basement walls, the roof, and the exterior walls
Air leakage
Use a sealed air/vapour barrier to reduce air leakage and the buildup of moisture
The barrier is made of plastic and is placed on the inside of the insulated walls
Windows and doors
Basement walls
Install windows that are either double or triple glazed/paned or use storm windows
Use doors made from good insulating materials or use a double door system
Ensure that all windows and doors have tight weather seals
Lack of exposure to sunlight
Face home toward the Sun (east-west, southern exposure); use special designs to take advantage of solar energy
Screen of evergreen trees protect north side from cold winds
Screen of deciduous trees shade south-facing windows in the summer

7. HEATing homes Forced Air Heating Systems: In forced air heating
systems, air is heated in a
furnace and then driven by
a fan through ducts to the
rooms

8. HEAT CAPAcities
Different substances heat up (or cool down) at different rates
The heat capacity of a substance = a measure of the amount of heat needed to raise the temperature of the substance = a measure of how much heat the substance releases as it cools

9. HEAT CAPAcities Heat Capacity and Climate: Why are Regina, Winnipeg,
and Quebec City so cold?
What makes Victoria, Toronto,
and Halifax warmer in winter?
Heat Capacity and Solar Heating:
How can the Sun’s radiant
energy and knowledge of heat
capacities help to design a solar
heated home?
Consider how water and
concrete absorb radiant energy

10. producing heat Energy sources can be grouped as…
Renewable = not destroyed in the process of being used
ex) solar energy, electricity produced from moving water
Non-renewable = gradually used up or may run out entirely
ex) coal, oil
Four Ways of Producing Heat:
Mechanical Energy - (changes into heat and sound)
Note:
A mechanical force = a force caused by objects in contact with each other

11. producing heat
a) Friction - an example of a mechanical force occurring between objects in motion that are touching (between solids, or between a solid and a fluid) b) Distortion - occurs in objects that are stretched or forced to move back and forth

12. Producing heat
c) Percussion - occurs when objects are pounded d) Compression - occurs when, air for example, is forced into less space; often increases pressure

13. producing heat
Four Ways of Producing Heat Continued… 2) Chemical Energy - stored in fuels such as oil, wood, coal, natural gas (changes into heat and light) 3) Electrical Energy - needs electricity to change to heat (→ heat and light) ex) in a stove, an electric current passes through an element made of a material that resists the flow of electricity. The resistance causes the element to heat up. The greater the current, the hotter the element becomes (red – stove, white – light bulb)

14. producing heat
Four Ways of Producing Heat Continued… 4) Nuclear Energy - energy stored in the nucleus of atoms - energy can be changed into other forms of energy, such as heat, via different processes → Nuclear Fusion – nuclei join and some mass changes into energy ex) the Sun → Nuclear Fission – nuclei split and some mass changes into energy ex) uranium Ex) Nuclear stations: nuclear energy → heat (to heat water) → mechanical energy (spinning turbine) → electrical energy + heat

15. Solar heating
There are two basic ways of using solar energy to provide heat
1) Passive Solar Heating:
- the system lets the solar energy in and prevents much heat from getting out
- is not expensive and is easy to maintain
ex) most homes use passive solar heating simply by allowing sunlight to shine in the windows
Ex) Greenhouse Effect:
= the process of trapping radiant heat inside a structure

16. Solar heating
ex) Greenhouse Effect = the process of trapping radiant heat inside a structure

17. Solar heating
2) Active Solar Heating: - the system absorbs as much solar energy as possible and distributes it throughout the building - usually requires another source of energy besides the Sun, at least as a backup during times of little sunshine