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It’s the good ‘ole summertime!
The time when thoughts often turn to picnics and barbecues!
Yup, it is that time of year – the time for summer cookouts and get-togethers. And, hopefully, no food-borne illnesses!
Did you know the Centers for Disease Control and Prevention (CDC) estimates that 48 million people get sick from a foodborne illness, 128,000 are hospitalized, and 3,0o0 die, each year (emphasis mine).
There are things that can be done to keep you, your friends, and family from becoming one of those statistics. We have the resources to help you stay safe, although according to Jeff Potter, author of Cooking for Geeks: Real Science, Great Hacks, and Good Food, there is “no such thing as 100% safe.”
Planning to marinate meat to grill? Potter warns: “… recipes that say that say to marinate at room temperature: don’t! Let it marinate in the fridge.” That is because of the “danger zone rule.” Bacteria which is related to foodborne illnesses begin to multiply above 40°F/4.4°C. The standard safety rule provided by the FDA says that food should not be held between the temperatures or 40°F/4.4°C and 140°F/60°C for more than 2 hours. Bacillus Cereus has the highest survival temperature, at 131°F/55°C. (Potter notes: “Who said scientists don’t have a sense of humor? Try saying B. Cereus out loud.”)
Here’s a Fun Fact: “hamburger” can have beef fat added to it; “ground beef” can’t!
Salmonella is one of the most well-known foodborne illnesses. But, the primary source of salmonella isn’t chicken or meat, but vegetables and fruits. So, be sure to wash those fruits and veggies!! A single bacterium of salmonella probably won’t cause a problem, but a few dozen cells will dramatically increase the chances of illness. Norovirus (from the family of caliciviruses) also receives a good deal of attention. The norovirus is contracted when a sick person prepares food for others. For more information and a list of pathogens and the foods which may be carriers head over to Wiley Online. (You’ll need to sign on with your Hawk ID and password).
Note: “… Salmonella is killed at 136°F only when held for a sufficient length of time…” Seeing your thermometer register a hotter temperature does not guarantee the food will be free of salmonella. For more information check out the U.S. Food & Drug Administration’s Bad Bug Book.
Did you know that serving spoons are supposed to stay in the food? This insures they stay above the 140°F temperature. “Otherwise, that mashed potato clinging to the serving spoon at room temperature will be a potential hangout spot for bacteria.”
When cooking meat, be aware that a change in the color is really not an accurate indicator of how done the meat is. “Myoglobin, oxymyoglobin, and metmyoglobin can begin to turn grey starting around 140°F/60°C, and they can also remain pink at 160°F/71°C if the pH is at or about 6.0.” It is important to use a thermometer when cooking ground meats and poultry!
Potato salad is notorious for spreading foodborne illnesses, but contrary to to what you might think, mayonnaise that isn’t the culprit! In fact, you could leave commercial mayonnaise out at room temperature and not worry about it making you ill. However, potato salad is often prepared and served at room temperature and it is often outside at a picnic or gathering at which there is no refrigerator. So, what does make potato salad so notorious? It takes 2-4 hours for staph or other pathogens to “get accustomed to their surroundings and really get ready to ramp up binary fission.” (Potato salad, food poisoning and contortionists). If the potato salad has been sitting for several hours at the right temperature, “trouble will ensue.”
If you are worried about bacteria multiplying and spreading in your food, remember this trick: FAT TOM.
F=Food: bacteria need proteins and carbohydrates to multiply, so obviously, no food, no bacterial multiplication!
A=Acidity: bacteria need certain pH ranges. Too acidic and proteins in the bacteria denature.
T=Temperature: Too cold – the bacteria sleep; too hot and they die.
T=Time: There needs to be enough time for the bacteria to multiply to a point where there enough to make a person ill.
O=Oxygen: Bacteria needs sufficient oxygen to multiply. (Note: Vacuum-packed bags ore not necessarily devoid of oxygen).
M=Moisture: Bacteria need water to reproduce. Bacteria need a water activity value of 0.85 or higher in order to multiply. (The water activity scae is used to measure the freely available water in a material – from 0 to 1).
Wondering how to accurately measure temperature? Head to our Tool Library webpage and explore the measuring devices that are available for you to check out! We have 2 thermal cameras, an infrared thermometer, environmental meter and more! Use our tools to help keep your food at safe temperatures!
Now that you are sure that your meats and potato salads will be safe for your outdoor party, you can think about what cold beverage you’d like to serve! How about making your own root beer? Homemade Root Beer, Soda, & Pop will explain the history and discuss the equipment needed to make them! It even includes recipes for ginger beer and cream soda!
Enjoy the summer grilling and picnic season! And, be safe!!
Potter, Jeff. 2010. Cooking for geeks : real science, great hacks, and good food. Sebastopol, CA : O’Reilly First Edition. Engineering Library TX715 .P88 2010
Foodborne Illnesses and Germs. Feb. 15, 2018. Centers for Disease Control and Prevention.
Bad Bug Book. 2nd Edition. U.S. Food & Drug Administration. Date Accessed: July 2019
Revere. Jan. 10, 2010. Potato salad, food poisoning and contortionists. Science 2.0. ScienceBlogs. Date Accessed: July 2019.
Cresswell, Stephen Edward. 1998. Homemade root beer, soda & pop. Pownal, VT : Storey Books. Engineering Library TP630 . C74 1998
Satin, Morton. 2008. Food alert : the ultimate sourcebook for food safety. New York, NY : Facts On File. Engineering Library RA601.5 .S28 2008
Lawley, Richard; Laurie Curtis; Judy Davis. 2008. The food safety hazard guidebook. Cabridge :RSC Pub. Engineering Library RA601 .L39 2008
Kuhne, Cecil C. III. 2013. The little book of BBQ law. Chicago : American Bar Association. Law Library KF1250 .K85 2013
Nemerow, Nelson L. 2009. Environmental engineering. Prevention and response to water-, food-, soil-, and air-borne disease and illness. Engineering Library RA643 .E58 2009
Can you imagine a life without tools? We can’t! And you don’t have to! We have approximately 233 tools in our Tool Library – and are always adding more!
We have all sorts of things! We have laptotps and iPads, chargers and cables, hammers and screwdrivers, 3D scanners and hot glue guns, GoPro cameras and Raspberry Pi – all available to check out! We also have an Occulus Rift for use in the library!
Need a video game screwdriver set? We’ve got that! Wire cutter/stripper? Yup, we’ve got that. Sound level meter? We have that, too! Multimeter? Projector? Heat Gun Kit? Oscilloscope? Yes, yes, yes, and yes! We have those!!
We have 3D scanners, cables and chargers (63!), 5 laptops, 12 iPads, calipers, a 25-foot tape measure, speed gun, wrenches, pliers, screwdrivers, socket set . . .
And, we have just added 2 Video Conference Meeting Cameras (Owls) and a vibration meter!
Hardord, Tim. 2017. 50 Inventions That Shaped the Modern Economy. New York : Riverhead Books. Engineering Library T15 .H343 2017
Worship of Tools Day : 2019 National Worship of Tools. Dayfinder.com Date accessed: March 2019.
Do you remember lying on your back on the grass and looking at the clouds – finding the shapes, marveling at all the differences? The types, the colors? Looking through old family slides and photos I discovered my father took a lot of pictures of clouds – as do I, my brother and my daughter. There is just something endlessly fascinating about them.
Here in the library we have, not surprisingly, a lot of books on the physics and chemistry of clouds (for resources, check the list below). But for this blog, I’m going to draw on the appearance of clouds in arts and culture. Perhaps it is their beauty and majesty that has attracted scientists to the study of clouds, for that has what has drawn poets, painters, songwriters, and photographers throughout the ages. (Interesting fact: The art of seeing shapes in shapeless forms is pareidolia.)
An example of how far back clouds appear in literature, back in the fifth-century, the playwright Aristophanes, “cast a chorus of clouds as the source of ‘airy’ thinking. (pg 7, Clouds). Indeed, there are many sayings about clouds: “head in the clouds,” “nebulous,” “foggy,” and “cloud the issue.” Richard Hamblyn, author of Clouds, wonders if the saying “on cloud nine” might come from a story from the early life of Buddha. The story is that Buddha summoned a small cloud which ferried him over the Ganges, and “the Buddhist cosmology contains a tenfold cloud taxonomy whose stages mirror the tenfold ascent to enlightenment.” The 9th step is “the great bright clouds of refuge,” hence (perhaps) being on cloud nine! There are also frescoes and paintings as clouds from as far back as the 1200s. The fascination with clouds has a long history!
From the early days of photography, photos have been taken of clouds and storms. We may be used to taking cloud photos with our DSLR cameras, or our phones, but the technology in those early days made taking good photos very difficult. It took minutes, not seconds, to take a photo using the photographic plates, and those minutes often made the sky overexposed. One solution, used by many photographers, was to take extra, under-exposed photos and superimpose them over the overexposed plate. Superimposing one photo over another can be used in digital photo editing programs – there has been some controversy concerning the use – and overuse – of digitally edited photos. However, that practice has been going on a long time!
Talking about clouds and photography wouldn’t be complete with touching on clouds and storms in movies and videos. While we are talking tornadoes (see photo at left!), the famous tornado in The Wizard of Oz was constructed from a muslin wind-sock which was suspended from a metal gantry. It is still considered to be one of the most convincing tornadoes in Hollywood history!
And then there’s the music – see the Joni Mitchell quote above. Music and clouds just seem to go together. In 1867 the French astronomer and science writer Camille Flammarion was floating in his hot air balloon. He drifted into a high, thick cloud and could no longer tell in which direction he was traveling. Suddenly he heard instrumental music “which seem[ed] to come from the cloud itself and from a distance of a few yards only from us.” There was high humidity in the cloud and this helped funnel a band concert which was playing in a town square far below. Recently artists have begun to explore the acoustic resonance of the upper atmosphere. In 2004 Usman Haque launched Sky Ear – a cloud of 1,000 helium balloons with a payload of mobile phones, sensor circuits, and flashing LEDs. The phones picked up the whistles and hums that fill the sky – the phones were set to automatically answer therefore letting observers call the phones and listen to the “music of the spheres.”
Musicians and songwriters have long gotten their inspiration from clouds. Here’s a (very) short list (in no particular order)!
And the list goes on and on!!
If you are someone who goes around with your “head in the clouds” most of the time there is The Cloud Appreciation Society. Really! It now has over 40,00 members from nearly 120 countries! The society has recently teamed with NASA and have a Cloudspotter app. The information gathered submitted by the app users (from around the globe) will be used by NASA to help calibrate their CERES cloud-observing satellite instruments! You can continue to look up to the skies and help NASA at the same time!
If signing up with the Cloudspotter app isn’t your thing, but you still want to know which clouds are which and what differentiates one cloud from another, The Cloud Book : How to Understand the Skies, has a wealth of information about clouds accompanied by stunning, full-color photographs of each type of cloud.
Here’s a Sky Watcher Chart. Go out – look up! How many different types of clouds can you see?
Hambly, Richard. 2017. Clouds. London, UK : Reaktion Books, Ltd. Engineering Library QC921 .H35 2017
Lohmann, Ulrike. 2016. Introduction to Clouds, Aerosols and Precipitation. Cambridge University Press. Engineering Library QC921 .L74 2016
CloudSpotter : Your virtual guide to the wonders of the sky. The Cloud Appreciation Society. Date accessed: June 14, 2018.
Hamblyn, Richard. 2008. The cloud book : how to understand the skies. Cincinnati, Ohio : D&C David & Charles : In association with the Met Office. Engineering Library QC921 .H348 2008.
Qiu, Meikang; Keke Gai. 2017. Mobile cloud computing : models, implementation, and security. Boca Raton : CRC Press, Taylor & Francis. Engineering Library QA76.585 .Q58 2017
Randall, David A. 2012. Atmosphere, Clouds, and Climate. Princeton : Princeton University Press. Engineering Library QC981 .R36 2012
Lohmann, Ulrike. 2016. Introduction to Clouds, Aerosols and Precipitation. Cambridge University Press. Engineering Library QC921 .L74 2016
Baianov, I. M. 2011. Cloud Formation. New York : Nova Science Publishers. Engineering Library QC921.6 D95 B35 2011
I am, obviously, not talking about the vast field of cloud computing – that is beyond the scope of this blog. However, if you’d like more information about cloud computing, check the resources below!
Ruparelia, Nayan. 2016. Cloud Computing. Cambridge, Massachusetts : The MIT Press. Engineering Library QA76.585 .R87 2016
Foster, Ian. Dennis B. Gannon. 2017. Cloud Computing for Science and Engineering. Cambridge, Massachesetts : The MIT Press. Engineering Library QA76.585 .F67 2017
The next chapter in the Star Wars© franchise will be released at the end of this week. Have you ever wondered about physics in that galaxy far, far away?
How did Han Solo and the Millennium Falcon make the Kessel Run in under 12 parsecs, when a parsec is a unit of distance and not of time? Is it possible to build a podracer with our current technology? How about lightsabers – are they laser (i.e, light) or contained plasma? Could we possibly live in a cloud, like Cloud City on Bespin? And, in my mind at least, the ultimate question – is there actually a Force, a field what surrounds and penetrates all beings?
Author Patrick Johnson explores these and oh, so many more fascinating topics in The Physics of Star Wars. In sections ranging from Space, Planetary Science, Space Travel, Handheld Weaponry, Heavy Weaponry, the Force, Robotics, and other tech, Johnson provides a brief introduction, and then the backstory, before delving into the actual physics. He then progresses into “the physics of real life.”
Let’s look at the climates on various planets. For example, Hoth is an “ice planet.” The fact that Hoth is an ice planet is consistent with its distance from its star – that’s what we see in our own solar system. A big difference, however, is that Hoth has snow and frozen planets are generally made up of frozen nitrogen or methane, and not water. No water, no snow. Also, the temperatures would be so low that surviving in a tauntaun would be impossible…. Tatooine, on the other hand, is very hot and dry – consistent with having two suns. And that leads us to moisture farming. If an environment doesn’t provide easy access to water, organisms (in this case, humans) are inventive and find other ways to distribute the water necessary for life. Thus, moisture farming is developed on Tatooine. Luke Skywalker’s Uncle Owen’s moisture farm uses moisture vaporators. Basically, ambient air flows into the vaparator, the air comes into contact with a coiled pipe using some sort of coolant, which causes some of the moisture in the air to turn into water which is then collected and saved for later. Possible here on earth? Peru’s University of Engineering & Technology has combined atmospheric water generation and advertising. Yes, advertising. They designed a billboard which pulls water from the air, filters it, then delivers it to a cistern. Moisture farming on earth? Possible and happening!
Now. The Millennium Falcon. How can it make the Kessel Run in under 12 parsecs when a parsec is a unit of distance? Johnson explains it using an ant analogy. Two ants are walking at the same pace and moving from point A to point B. In the direct path is an antlion (think sarlacc). Ant 1 walks the long way around the antlion for safety. Ant 2 walks a bit closer to the antlion. Ant 2 will have traveled to point B in fewer parsecs than ant 1. Now add in varying speeds (because what would a race be if everyone was traveling at the same rate of speed?). So ant 2 is not only braver (by walking closer to the antlion) but also faster than ant 1. Voilà! The Millennium Falcon has now made the Kessel run in fewer than 12 parsecs!
How can twins, Luke and Leia, be different ages? In A New Hope, Luke is described as being 20 years old, while Leia is supposedly 18 years of age. What about Jedi mind tricks? Or the fascinating robotics of R2-D2, C-3PO, or BB-8?
For answers to these, and many other, fascinating facets of the Star Wars universe, you’ll have to check out The Physics of Star Wars! I shall share no more physics spoilers!
Johnson, Patrick. 2017. The Physics of Star Wars : the science behind a galaxy far, far away. Avon, Massachusetts : Adams Media. Engineering Library QC75 .J64 2017
Want more Star Wars?:
Burton, Bonnie, 2011. The Star Wars craft book. New York : Del Rey/Ballantine Books. Engineering Library TT157 .B87 2011
More on space flights?
Guthrie, Julian. 2016. How to make a spaceship : a band of renegades, an epic race, and the birth of private space flight. New York : Penguin Press. Engineering Library TL795 .G88 2016
Friedman, Louis. 2015. Human spaceflight : from Mars to the stars. Tucson : The University of Arizona Press. Engineering Library TL788.5 .F748 2015
Wohlforth, Charles P. and Amanda R. Hendrix, authors. 2016. Beyond Earth : our path to a new home in the planets. New York : Pantheon Books. Engineering Library TL790 .W63 2016
If you are like me and are driving through a rock tunnel (like the one below in Custer State Park, South Dakota), you might be amazed at how sturdy it is and a little afraid of the “Falling Rock” sign. But, again, if you are like me, you’ve probably not given more than a passing thought to how the tunnel was created and what keeps it from collapsing…
Part of the answer is “rock bolting.” According to dictionary.com, the term “rock bolt” was first recorded between 1955 and 1960 and is the “steel or fiberglass bolt inserted and anchored in a hole drilled in rock to prevent caving of the roof of a tunnel or subterranean chamber.” The use of rock bolts goes back much further than 1955, however. The use of rockbolts was documented at the end of the 1800s, and in the 1900s, it was introduced in coal mines.
And, in November 1930, the Detroit-Windsor Tunnel was dedicated. It is a 5,160-foot-long tunnel between the cities of Detroit, Michigan, and the Canadian city of Windsor, Ontario. The first passenger car to drive through it was a 1929 Studebaker. The first Michigan-to-Canada tunnel opened in 1891 – the 6,000-foot-long Grand Trunk Railway Tunnel. During the first 9 weeks the Detroit-Windsor Tunnel was open nearly 200,000 cars passed through it. Today, around 9 million vehicles use it each year!
On December 1st, 1990 workers – 132 feet below the English Channel – drilled a car-sized opening through a wall of rock! The “Chunnel” (Channel Tunnel) connects Great Britain with the European mainland. It took nearly 13,000 workers four years to dig 95 miles of tunnel. The average depth of which is 150 feet below sea level. The cost? $15 billion….
As one might expect, the process of rockbolting is complicated and there are different types of rock bolts for different situations. The reinforcement function of a rockbolt depends on the load carried on the bearing plate. That loading pattern is dependent on rock mass quality, rock joint pattern, rock stresses, and the anchoring mechanisms of the bolt.
Rockbolts are generally made of steel and their design is based on how they are used. Some typical rockbolts include the mechanical rockbolt, slot-and-wedge rockbolt, and a grouted rockbolt. There is even an inflatable rockbolt! For more information on these, and many more, refer to the chart (left) and our resource Rockbolting: Principles and Applications.
Rockbolts do fail – especially during dynamic load shifts, often after a rockburst (a sudden, violent, rock fracture). For a quick look at a rockburst check out this video! Needless to say, there is a lot of quality control and testing which must happen with rockbolts. The quality and composition of the steel used in rockbolts is obviously critically important. There are also design proof tests, and viscosity tests of the cementitious grout. Along with the quality control on the mechanical properties of the rockbolt, there are many tests that are done on-site. These include pull tests, proof tests, and the inspection of boreholes.
If you are thinking of building a rock tunnel, there is, not surprisingly, lots of pre-planning, site investigations and testing that must be done before the actual building can begin. Practical Guide to Rock Tunneling is just that, a guide explaining the planning process and what needs to be taken care of – including the design, drainage requirements, rock strength, and practical considerations (among many others!). It is full of photos – many in color – of the various stages of tunneling and the equipment used. There are also a number of tables and graphs detailing everything from historical failures of hydraulic pressure tunnels (figure 6.3) to a critical path construction schedule example (figure 14.1) to a risk matrix for quantitative assessment (16.3).
Whether you are planning a career in tunnel building – or thinking ahead to tunneling out of a snow fort this winter – be sure to check our resources. We’ll help you dig through . . .
Brox, Dean. 2017. Practical guide to rock tunneling. Leiden, The Netherlands : CRC Press/Balkema. Engineering Library TA805 .B75 2017
Li, Charlie Chunlin. 2017. Rockbolting : principles and applications. Oxford Buttenworth-Heinemann. Engineering Library TA772 .L5 2017
International Symposium on rock Fragmentation by Blasting. A.T. Spathis. 2013. Tunnelling in rock by drilling and blasting : workshop hosted by Fragblast 10 : the 10th International Symposium on Rock Fragmentation by Blasting, New Delhi, India, 24-25 November, 2012. Boca Raton : CRC Press. Engineering Library TA800 .I58 2012.
1930, Detroit-Windsor Tunnel is Dedicated. This Day in History. November 1. History. A&E Networks. Date Accessed: January 2018
Kaiser, Peter, K.; Ming Cai. 2015. Design of rock support system under rockburst condition. Journal of Rock Mechanics and Geotechnical Engineering. vol. 4, issue3, 25 Sept. 2012, pgs 215-227. Science Direct .
rock bolt: Word origin: 1st recorded in 1955-60. noun, Mining, Civil Engineering. 1. a steel or fiberglass bolt inserted and anchored in a hole drilled in rock to prevent caving of the roof of a tunnel or subterranean chamber. — dictionary.com
Chunnel makes breakthrough. This Day in History, Dec 01. History. A&E Networks.
So, it’s winter. You are tired of being cooped up inside. You need exercise (and not on a treadmill). You need fresh air. Got snow? Why not build an igloo?
A great way to spend some time in the great outdoors – fresh air, exercise – fun with your family and friends! So, let’s get started!
According to Norbert E. Yankielun, author of How to Build An Igloo and Other Snow Shelters, the first thing to do is “make friends with winter.” Which makes sense since you’ll be outside working with snow – it’s cold out there and you don’t want frostbite, dehydration, or hypothermia. To protect yourself, you’ll want to be sure to have the right clothing, nutrition, and water. You may already know that several layers of clothing are the best way to insulate yourself from losing body heat. But, you do want to avoid wearing cotton clothing because it absorbs and holds water and moisture. Similarly, you’ll want to wear mittens (which are warmer than gloves) that have a waterproof shell to keep your hands dry. And, don’t forget the sunscreen and UV-blocking sunglasses or goggles – the sun glaring off white snow intensifies the damage to skin and eyes.
So, what else do you need to know to make your own backyard igloo? It is possible to build an igloo by yourself – but what fun would that be? It is also much safer to build with another person. If you are building in an urban setting there are some “don’ts” about which you should know. Avoid the piles of snow near parking lots, streets, driveways, etc., a plow driver could easily mistake an igloo for another pile of snow. You also don’t want to build too close to parking lots, roadways, or driveways to avoid the possibility of car exhaust and carbon monoxide poisoning.
So, you have a safe spot picked out and a group of your friends/family. What else do you need?
Snow. You have to have snow to build an igloo (obviously). There are lots of different types of snow – which are beyond the scope of this blog. What you want for a good, strong igloo is sintered snow. Sintering is what happens when you compress snow into a snowball – it squashes the flakes, briefly melting the edges and then re-freezing into a snow mass. It also occurs when snow goes through melt and freeze cycles. Don’t have sintered snow in your yard? Stomping the snow underfoot is one of the easiest ways to create the snow blocks you’ll need for your igloo.
Now, what tools do you need? For the recreational igloo builder, ordinary tools will suffice. A carpenter’s saw will work nicely to cut blocks of snow – but cutting snow will ruin the blade for much of anything else. Buy an old blade at a garage sale! A flat-handled show shovel – the kind used for clearing sidewalks and drives – works great (avoid the “pusher” type shovels). The ideal shovel is a grain scoop…
You are with your family and friends, have snow, are dressed in layers and have assembled your equipment. What’s next?
Once you find a nice, flat area for your igloo, you’ll need to size your igloo and flatten the floor. An igloo large enough for 2-3 people should have a diameter of at least 6 feet. Have ski poles? Plant one to use as the center and use the other to draw the circle around it. Or for more fun, have the tallest person in your group make a snow angel – that will give you approximately the right sized igloo for two people! Then if you all get together and stomp around inside the circle, you’ll tromp down the snow into a nice foundation!
If you have sintered snow, take your saw and start cutting your blocks! Blocks need to be the same size and it is suggested they be about 18 to 24 inches long, 9 to 12 inches thick, and 12 to 18 inches tall.
Don’t have sintered snow? No worries, you can also use a clean bucket, or storage tub and pack the snow in that. When you turn it upside down you have your snow block! Got those ice blocks made? Time to start building that igloo! Place them, edge-to-edge, on your circle. Once you have the first layer made, you’ll want to cut the blocks into a ramp which should go at least halfway around the block circle. Now you can begin stacking the blocks on the ramp base. You’ll probably have to cut the edges of the blocks so they will fit tightly together. In order to form a stronger structure, you’ll want to be sure the block bridges the seam of the two blocks beneath it. It is helpful to have one person inside the igloo to help place and shape the blocks and to help place the cap block (or King Block) on the top of the igloo! The cap block has to be carefully shaped so it will support the inward leaning of the walls.
Yes, you have now enclosed one of your party inside the igloo with no way out! Making the entrance before the dome is complete weakens the entire structure, so that part of the construction must wait. (Might be a good idea to make sure the person on the inside isn’t claustrophobic!) There are a couple of options to consider when planning your entrance. One option is the “gopher hole.” A gopher hole is basically building a tunnel under the wall of the igloo – an advantage is it helps keep the heat inside the igloo! The other option is a surface entry, which I suspect, is what we think of when we visualize an igloo. It is an arch-shaped entry cut into the side of the igloo. Using an arch shape helps reduce the stress on the shell of the igloo when creating a hole in the wall. It shouldn’t be larger than 2’x2′ – just large enough to crawl through.
These are the basics of igloo building – be sure to check our resources before you start your own! Learn from the experts!
There are other types of snow shelters: quinzees (a hollowed out, dome-shaped mound of well sintered snow); slab shelters (looks like a pup-tent or A-frame); drift caves (similar to a quinzee – only in a hollowed snow drift); and spruce traps (using the umbrella of a spruce, pine, or other evergreen tree as a shelter). How to Build an Igloo and Other Show Shelters is a great source of information about these shelters and how to build them!
Be sure to check out Igloo : Contemporary Vernacular Architecture – it is an absolutely fascinating look at modern architecture and the influence the igloo has played!
Want to see the Guinness World Record holder for largest snow dome igloo ever built? Check this out!
Yankielun, Norbert E. 2007. How to build an igloo : and other snow shelters. New York : W.W. Norton. Engineering Library TH4890 .Y36 2007
Bahamon, Alejandro, Ana Canizares, editors. 2012. Igloo : contemporary vernacular architecture. Atglen, PA : Schiffer Publishing, Ltd. Engineering Library TH4890 .I35 2012
Hewings-Martin, Yella. Jasmin Colllier, Fact Checker. Nov. 7, 2017. Why am I cold when nobody else is? MedicalNewsToday. Healthline Media UK Ltd.
National Film Board of Canada. Jan. 6, 2015. How to Build an Igloo. youtube.
How to Build An Igloo. NOVA. PBS.
Igloo 101. arcticPassage. NOVA Science Programming on Air and Online. Date assessed 12/06/17
Heid, Matt. March 1, 2012. Snow Sintering: How to Get Cohesive Snow for Building Snow Walls and Snow Shelters. Appalachian Mountain Club; AMC.
Photo Credit: How to Build An Igloo. NOVA. PBS.