The Wonders of Igloo

1. The Wonders of Igloo Done by: Wong Hong Jie 3S430

2. The igloo… • The Inuit word for “house” • Invented by Eskimos thousands of years ago • Small • Dome-shaped • Made entirely out of ice • Small tunnel leading to the igloo • On the outside, temperatures may be as low as −45 °C, but on the inside the temperature may range from −7 °C to 16 °C when warmed by body heat alone.

3. Constructing an igloo • An ancient skill passed down from generation to generation… • Construction begins with the cutting of snow blocks. • Snow blocks must have sufficient structural strength to be cut and stacked in the appropriate manner. • The best snow to use for this purpose is snow which has been blown by wind, or gone through compaction. • Compaction causes the small ice crystals of snow to melt and quickly refreeze to form a more solid building material. • The size and shape of the blocks will depend on which part of the dome the block is placed.

4. Constructing an igloo • Constructed on flat surfaces, usually below ground level. • Place the blocks in a circle, this will be the first layer. • Overlap the blocks with another layer and shape them to lean inward, creating the dome. Blocks will become smaller as it proceeds upwards. • Continue overlapping the blocks until the dome is constructed. Blocks should support each other to prevent from collapsing.

5. Constructing an igloo • Pack lose snow into crevices on the igloo. • Finish the entrance by digging a hole in the shape of the desired entrance. Then shelter the hole with snow blocks. • Small holes must be cut on the wall of the igloo for ventilation to prevent suffocation.

6. How does an igloo work? • Material- Snow and ice • Snow and ice work as thermal insulators and prevent thermal energy from inside the igloo to escape to the environment • Air pockets trapped in snow and ice are responsible for insulating properties.

7. How does an igloo work? • Walls • The walls block the wind, which is often so bitter that it can make freezing temperatures feel many degrees colder. • The heat inside the igloo gets reflected from the walls and the snow starts melting producing the insulating effect after freezing again. The temperature inside is maintained as to prevent the overheating. The dead vegetation used for making the floor can burn easily due to overheat.

8. How does an igloo work? • Walls • Insulation capabilities increase a few days after construction. Body heat and sun exposure cause the inside of the igloo to melt slightly. When the igloo is unoccupied during hunting expeditions, the melted snow freezes over, turning into ice. Several days of gradual thawing and refreezing turns the entire structure from snow to solid ice, strengthening the insulation of thermal energy.