The Igloo A Dome of Many Wonders

Outline • Igloo basics • Igloo science • Construction of an igloo • An igloo in Hyde Park

What is an igloo? • Comes from Inuit word for house • Usually means a dome-shaped dwelling made of snow • Not a quinzhee

Igloo Culture • Igloos were built by Inuit in the Canadian central arctic and Greenland’s west shore • Used mainly as temporary shelter on hunting trips • Larger semi-permanent igloos were also built that could house several families • Design of igloos varies between Inuit cultures

Igloo Physics • A hemisphere is not a good dome shape • Ideal dome shape is a catenary – Innuit design is very close to this ideal • Height/Diameter = 0. 3 for minimal stress • But compression shrinking so it’s best to make H/D > 0. 3 • Theoretical maximum size of igloo is: D = 34 ft. , H = 12 ft.

Igloo Physics • A hemisphere is not a good dome shape • Ideal dome shape is a catenary – Innuit design is very close to this ideal • Height/Diameter = 0. 3 for minimal stress at base • But compression shrinking so it’s best to make H/D > 0. 3 • Theoretical maximum size of igloo is: D = 34 ft. , H = 12 ft.

More Igloo Physics • Rate of heat flow through igloo given by where Q/t = heat flow per unit time, k = thermal conductivity, A = area of interior/exterior of igloo, Ti = interior temperature, To = exterior temperature, L = thickness of igloo • Can calculate Q/t in the interior making simple assumptions about people • Using reasonable values, temperature difference between inside and outside can be about 60 C

Construction of an Igloo • Snow must be packed • Cut wedge shaped snow blocks using snow saw • Lay blocks in helical pattern, cutting block thinner as you go up • Dig a trough leading into igloo and cover with snow blocks • Terrace interior to so that inhabitants are elevated • Cut ventilation holes

Block laying pattern

Construction of an Igloo • Snow must be packed • Cut wedge shaped snow blocks using snow saw • Lay blocks in helical pattern, cutting block thinner as you go up • Dig a trough leading into igloo and cover with snow blocks • Terrace interior to so that inhabitants are elevated • Cut ventilation holes

Igloo Side View

Igloos of the Future

Building an Igloo in Hyde Park • Problem: snow is not well packed – Solution: pack it into buckets • Problem: snow is cold and not fun to touch – Solution: buy a shovel • Problem: people throwing shit at your igloo – Solution: none

The location: 60 th and Drexel

Nick Igloo

STAGE 1: COMPLETE

The Finished Igloo!