3D Printing in construction

Image from article

Students in various fields of engineering find 3D printing to be an extremely interesting innovation. In an article I use as a model text for explaining how something works, the focus is on how 3D printing could eventually be used in large-scale projects in the construction industry.

The article is How to print a building: the science behind 3D printing in construction, by Seyed Ghaffar, Assistant Professor in Civil Engineering and Environmental Materials, Brunel University London.

Link to the article: https://theconversation.com/how-to-print-a-building-the-science-behind-3d-printing-in-construction-98490

In addition to being an interesting topic for my students, the article has many language features that I guide them to incorporate into their own writing, especially when writing a process description.

The first sentence of the article gives an indication of the intended audience of the article:

• It's often claimed that 3D printing -- known in the trade as "additive manufacturing" -- will change the way we live.

I call students' attention to the use of the phrase in boldface -- obviously it is focusing on those who are not "in the trade." There are other indications in the article that it is written for a non-expert audience.

• The simple approach of layer-wise construction -- where building materials are layered on top of each other to create a facade -- has already been practised for a long time in the construction sector, for example in conventional brick layering techniques.

Here, a description of what "layer-wise construction is" and a specific example of where this has already been used in construction are further examples of audience focus.

• One component is printable feedstocks -- the materials which are actually "printed" to create the final product.

And here, the term "feedstocks" is explained.

To describe how 3D printing could be used as well as what some of the problems are, there is language to present comparisons:

• But it's one thing to build small, prototype homes in a park -- it's quite another to ...
• Yet in some ways, it's not as ...
• But there is still some way to go before ...
• ... can work faster -- but it also puts the feedstock at risk of ...
• But before that can happen, ...

There is also language of cause and effect:

• so that the layers can be deposited rapidly.
• to achieve a robust structure which can take load.
• must be just right, so that ...
• need to be formulated and developed, so that this technology ...
• printer, which must have a power pump to suit ...
• The speed and the size of the printer is key to ...
• Decreasing the setting time of the feedstock means that the printer ...
• a constant rate, so that the layers can ...

The article has many examples of passive voice, which is contrasted with the use of the active voice; for example:

• To create materials for 3D printed constructions, scientists must carefully control (active voice) the setting time of the paste, the stability of the first few layers and the bonding between the layers. The behaviour of the materials must be thoroughly investigated (passive voice) under a range of conditions, to achieve a robust structure which can take load.

Other examples of the passive voice:

• It's often claimed that 3D printing -- known in the trade as "additive manufacturing"
• ... layer-wise construction -- where building materials are layered on top of each other to create a facade -- has already been practised for a long time
• ... to automate and improve processes that have already been proven manually. 
• ... different components of additive manufacturing, each of which must be developed and refined before the process can be successfully used ...
• ... the materials which are actually "printed"
• Printable feedstocks are typically made from a combination of bulk materials
• ... so that the layers can be deposited rapidly.
• ... and don't stay wet for too long once they have been deposited to form a structure. Different grades of feedstock need to be formulated and developed, so that this technology can be used to build a range of different structural elements, ...
• The pressure and flow rate of the printer must be trialled with different types of feedstocks.
• Only then can the potential of 3D printing be harnessed to build faster, and more sustainably, than ever before.

There is another useful contrast of vocabulary my students often have trouble with: the difference between fewer and less for count and non-count nouns in English:

• 3D printing can produce up to 30% less material waste, use less energy and fewer resources, enable in-situ production (which in turn cuts transports costs), grant greater architectural freedom and generate fewer CO2 emissions over the entire lifecycle of the product.

This sentence also has a variety of verb-noun collocations that are useful in technical writing:

• produce waste
• use energy
• use resources
• enable production
• cuts costs
• grant freedom
• generate emissions

Other noun-verb collocations:

• announce plans
• create a facade
• automate processes
• deliver on potential
• set concrete
• maintain shape

As a quick wrap-up to the lesson, I had students highlight verbs they thought could be used in different types of technical writing. This helps them to realize that they already know "technical vocabulary" because these verbs are quite common. Here's the list they came up with:

• build
• use
• layer
• create
• practise
• combine
• automate
• improve
• produce
• generate
• develop
• refine
• mix
• set
• maintain
• deposit
• investigate
• achieve
• formulate
• measure
• speed up
• slow down
• optimise
• fuse
• take load
• provide
• revolutionise
• harness

Since many of these verbs are used more than once, students can notice the different collocations used for them -- verb-noun, verb-preposition, or adverb-verb.

The article includes a link to a text on the Brunel University website for which Prof. Ghaffar is also an author: Additive Manufacturing Technology in Construction (AMTC). This can serve an example of how some of the same informaiton is written for an expert audience.

For example, information written first for the expert article, contrasted with the information from this (non-expert) article:

1. Additive manufacturing (AM) is a procedure that forms layers to create a three-dimensional solid object from a digital model.
2. The simple approach of layer-wise construction -- where building materials are layered on top of each other to create a facade, ...

Impact of concrete

My students learn impact analysis so they can understand the kind of impact their future innovations might have on the world someday as engineers -- including those impacts that were not intended. I have looked at this in a number of posts over the years. An article I used recently is about the impact of concrete: specifically, how concrete contributes to global warming.

The article is Feeling the Heat? Blame Concrete and the subtitle is particularly eye-catching: Concrete has transformed civilization -- but it's making our cities, and our world, hotter. So it is clear that the article looks at both the pros and cons of concrete.

Link to the article: https://time.com/5655074/concrete-urban-heat/?utm_source=newsletter&utm_medium=email&utm_campaign=the-brief-pm&utm_content=20190820&xid=newsletter-brief

A non-narrated video (56 seconds) on the same site as this article starts: "July 2019 was the hottest July and the hottest month on record globally since temperature records began."

As an argumentative, or opinion, essay -- looking at the pros and cons, it is very well structured in the English style: 

• Introduction: topic and specific focus of topic
• Advantages of concrete, with examples (2 paragraphs)
• Disadvantages of concrete, with examples (9 paragraphs)
• Conclusion: indication of future concerns

This, then, serves as a good model text for English essay organization. Since the main focus of the disadvantages is on how concrete contributes to global warming, there is also information about how this occurs. This includes useful phrases and collocations relating to heat:

• potency of heat waves
• soaks up and retains the sun's heat
• temperatures rise
• magnify that effect
• urban heat islands
• the heat released by vehicle engines
• boost the temperature
• soaring (city) temperatures
• a rapidly warming world

A useful feature for argumentative essays is the use of comparisons that the audience will understand (many of these focus on an American audience):

• If you've ever walked barefoot across a sunbaked parking lot, you know firsthand how concrete soaks up and retains the sun's heat.
• Heat already kills more Americans than hurricanes, lightning, tornadoes, floods, and earthquakes combined.
• That's the equivalent of adding nine New York Cities to the planet every year.
• ... making it the third-largest source of global-warming, behind only coal-fueled power plants and combustion-engine vehicles.
• ... enough to blanket the entire state of California.
• There is so much money to be made off of sand that in some countries, organized criminal gangs have moved into the business.
• We tend to think of concrete as permanent as the stone it mimics. It's not.
• America's dams are in similarly dismal shape.

Since the argumentation consists of information about the impact of concrete, there are many examples of cause and effect (with useful phrases in bold):

• When temperatures rise, the countless miles of concrete streets, sidewalks, walls and roofs in cities magnify that effect, creating a phenomenon known as urban heat islands. When combined with the heat released by vehicle engines, paved areas can boost the temperature in cities by as much as 22°F, ...
• The urban heat island effect is ever more worrisome because more and more people are moving into cities.
• Concrete is essentially just sand and gravel glued together with cement. To feed the construction industry's needs, tens of billions of tons of sand are dug out of the earth each year, enough to blanket the entire state of California. Much of it is dredged from river beds, lake bottoms, and beaches. The process often slaughters river-dwelling fish and birds, damages coral reefs, undermines bridges and causes riverbanks to collapse.
• There is so much money to be made off of sand that in some countries, organized criminal gangs have moved into the business.
• Heat, cold, chemicals, salt, and moisture all attack that seemingly solid artificial stone, working to weaken and shatter it from within. If it's not monitored and maintained, most concrete slowly disintegrates.

The final sentence is: "We can't stop using concrete completely; it's far too useful as a building material. But in a rapidly warming world, we need to start thinking about its true costs."

It would be interesting to see what engineering students would propose as a solution to this -- and it might depend on which field of engineering they are studying.

The author of the article is Vince Beiser, who is mentioned as the author of the book, The World in a Grain: The Story of Sand and How It Transformed Civilization. I haven't read this book, but it certainly sounds as if it is all about impact. Perhaps there are students or teachers who would be interested in reading it!

How to launch a rocket from a plane

Virgin Orbit / Greg Robinson

In January, the firm Virgin Orbit successfully launched a rocket from a plane. The LauncherOne rocket carried 10 of NASA's satellites and was brought 11 kilometers (6.8 miles) into the atmosphere by a modified Boeing 747. The article I used is called "Virgin Orbit launched a rocket from a plane -- here's how" by Simon Lindsay, a Researcher in the School of Physics and Astronomy at the University of Leicester. It describes how this was done -- clearly and concisely in the first 3 paragraphs -- and explains why this was an important development for space travel.

Link to the article: https://theconversation.com/virgin-orbit-launched-a-rocket-from-a-plane-heres-how-154207

The explanation of how this was accomplished is an excellent example of a process description, which my students have to learn how to do in both writing and speaking. In addition, there are examples of making this explanation clear to a non-technical audience - and this is something I find useful to bring to students' attention so that they use it in their own explanations. For example:

• Earlier this month, ten cubesats -- small, cheap satellites weighing about a kilogram each -- were sent into orbit around Earth.
• With almost 1,500 of these small satellites launched so far, adding another ten might seem trivial. But this was no ordinary launch.
• But how does launching a rocket from a plane actually work?
• Usually, a rocket launched from a launch site on the ground will have two or three stages, which allow the rocket to shed weight as it uses up fuel.
• ... the payload -- the part we want to get into space -- ...
• ... but most of the fuel requirement to achieve orbit is not in gaining height, but getting it moving with enough speed so that it falls into orbit.
• For small satellites, cubesats, micro-satellites and nano-satellites -- all of which are being rapidly adopted by the space industry -- air launches could represent ...
• The idea of air launching has been around for some time.
• ... which may be able to place smaller satellites -- 50 kg or so -- into much more distant orbits ...

In describing both the process and the advantages of this process, there is a variety of adverbs used, which combine to form useful collocations. My students either do not use many adverbs or they confuse their use with adjectives. But in the article, adverbs are used to be more precise, which is also something students should use in their own writing. Some examples:

• actually work
• typically places (the noun)
• repeatedly delayed
• can simply be flown
• can easily be accommodated
• a relatively small (noun)
• being rapidly adopted by
• an improvement in versatility and, crucially, cost
• aims to fully combine (noun and noun)
• an increasingly competitive market
• relatively low cost

The next feature I highlight for my students is the use of "referents" -- words or phrases that refer to something already mentioned. In their writing, my students often keep repeating the same word, which produces an inelegant, repetitive text. I ask students to identify what a specific term refers to -- either in the same sentence or in a previous sentence -- so they can see how this can be done. In this article, there are many uses of "its," which helps students see how this word is used and (hopefully) how not to confuse it with "it's" (of which there is only 1 in the text). Some examples:

What does (italicized term) refer to in the following sentences:

• The plane carried them to a height of 11km ...
• This was the first successful launch of Virgin Orbit's LauncherOne rocket, marking the start of its commercial ventures. The company hopes to ...
• A third stage operatres on the same principle and ...
• Air-launching takes advantage of this by attaching a rocket to an aircraft and releasing it ...
• Stratolaunch, the developers of the enormous carrier aircraft of the same name able to carry a rocket weighing 250 tons, abandoned its heavy-lift launch vehicle program in 2019.
• While the flight speed of an aircraft can make a small contribution to this requirement, the fuel saving from air launch is not as large as it might first appear.
• The Pegasus launch service is still operational, and has completed 30 successful flights, but its launches are expensive ...

While I like to focus on the useful language features of this article, my students are interested in the topic and the possibilities for the future.

Engineering humor

My material for classes with engineering students doesn't usually involve intentional humor, but after coming across various "engineer jokes" on the internet, I shared some of them with my students. It was not only a nice break during the lesson, but it also started discussions about aspects of engineering and/or cultural aspects of humor.

One of the first engineer jokes I remember hearing was:

• An optimist says the glass is half full, a pessimist says the glass is half empty, and an engineer says the glass is twice as big as it has to be.

Do cultures other than English-language ones have the concept of the half-full (optimist) and half-empty (pessimist) glass? What are the different concepts that different cultures joke about - or would not joke about?

To bring some of these questions into lessons, I searched the internet for jokes specifically about engineers or engineering, and it turns out there are a lot of them! The first article I focused on was "25 Best Engineering Jokes That Will Make Your Day Better," written by Christopher McFadden on the website interestingengineering.com (see my Relevant Links):

https://interestingengineering.com/25-best-engineering-jokes-make-your-day-better

Which jokes could be translated into students' language(s) and which are dependent on English language or English-culture ideas? For example, jokes that depend on puns for their humor cannot be directly translated into another language. One of the engineering jokes in the article puns with the words four and for and with what and watt:

• Customer: Do you have any two-watt, 4-volt bulbs?
• Sales Rep: For what?
• Customer: No, two.
• Sales Rep: Two what?
• Customer: Yes.
• Sales Rep: No.

Some jokes require certain technical knowledge to understand why it's intended to be funny. One joke in particular, referred to as "the most brilliant joke ever written," I didn't understand at all until my students explained it to me:

• One day, Einstein, Newton, and Pascal meet up and decide to play a game of "hide and seek." Einstein volunteered to go first. As he counted, Pascal ran away scrambling to find a great hiding place. Giddily, he squeezed into a crawl space sure that he would win this time, as this was his best hiding spot to date and Newton surely wouldn't find an equal. Newton, on the other hand, stood right in front of Einstein, pulled out a piece of chalk, and drew a box on the ground of roughly 1x1 meters. Once this was completed, he sat down neatly inside the box and waited for Einstein to finish counting. When Einstein opened his eyes, he of course saw Newton and with a bit of disappointment said, "I found you, Newton, you lose." But Newton repliced, "On the contrary, you are looking at one Newton over a square meter. Pascal loses!"

If you don't understand the reason this is funny, I have given the reason at the end of this post.

There are links to other websites with engineering jokes, and many of them are the same as in this article. What is interesting about the language is that there are certain "templates" to jokes in English that can be seen throughout the choices. Some examples from the jokes in this article:

• An X, a Y and a Z (verb) ...
• A priest, a doctor and an engineer were waiting ...
• An engineer, a statistician and a physicist are out hunting ...
• Or, a variant: Three Xs were (verb)
• Three engineering students were gathered together discussing ...
• Why did the X (verb)?
• Why did the engineering students leave class early?
• Why does the Polish airline have ...?
• How many Xs does it take to change a lightbulb?
• How many nuclear engineers does it take to change a lightbulb?
• What's the difference between an X and a Y?
• What's the difference between an introverted and an extroverted engineer?

One of the jokes is a cartoon from the website XKCD, which I referred to in my post of June 7, 2013, titled Cartoons for ESL. The website is still current - and funny. Using humor in lessons can be an interesting change, and it breaks the stereotype of engineers as being humorless!

* Because 1 Pascal = 1 Newton/m2

Perseverance Mission landing

Source: NASA/JPL-Caltech

  This week - on 18 February 2021 - NASA's Perseverance Rover  landed on Mars safely. There is so much information about this mission from many different sources that it is difficult to choose what to focus on with engineering students.

  For my students, I chose materials from NASA's own website for the mission, which has further links to different asepcts of the mission and to information about Mars. The most attention-getting part is the video of the Perseverance landing, which was recorded by several high-definition cameras located under the spacecraft. 

The video last 3:25 minutes; English subtitles of the audio embedded in the video are available.

Link to video: https://www.nasa.gov/press-release/nasa-s-mars-perseverance-rover-provides-front-row-seat-to-landing-first-audio

As indicated in the accompanying text, Thomas Zurbuchen, NASA associate administrator for science, says, "This video of Perseverance's descent is the closest you can get to landing on Mars without putting on a pressure suit." He goes on to say, "It should become mandatory viewing for young women and men who not only want to explore other worlds and build the spacecraft that will take them there, but also want to be part of the diverse teams achieving all the audacious goals in our future."

The link to the pages about the Perseverance mission: https://www.nasa.gov/perseverance

The website describes the landing and its challenges in a very clear way:

• "Entry, Descent, and Landing - often referred to as 'EDL' - is the shortest and most intense phase of the Mars 2020 mission. It begins when the spacecraft reaches the top of the Martian atmosphere, travelling nearly 12,500 miles per hour (20,000 kilometers per hour). It ends about seven minutes later, with Perseverance stationary on the Martian surface. To safely go from those speeds down to zero, in that short amount of time, while hitting a narrow target on the surface, requires 'slamming on the brakes' in a very careful, creative and challenging way."

I felt the focus on "a very careful, creative and challenging way" of solving a technical problem would be particularly relevant to my students. And the way that the writing continues sounds like a personal conversation, so it was both easy and appealing for my students to read. The lower register terms they identified are underlined:

• "Landing on Mars is hard. Only about 40 percent of the missions ever sent to Mars - by any space agency - have been successful. Hundreds of things have to go just right during this nail-biting drop. What's more, Perseverance has to handle everything by itself. During the landing, it takes more than 11 minutes to get a radio signal back from Mars, so by the time the mission team hears that the spacecraft has entered the atmosphere, in reality, the rover is already on the ground. So, Perseverance is designed to complete the entire EDL process by itself - autonomously."

The casual tone starts with a very basic sentence: Landing on Mars is hard. No scientific or technical language needed!

Since my students are generally interested in the technology created for the flight and the scientific mission, I also focused on the website page with an overview of the spacecraft:

Link: https://mars.nasa.gov/mars2020/spacecraft/overview/

There are 5 spacecraft components (also see the visual accompanying this post):

• Cruise Stage
• Backshell
• Descent Stage
• Rover
• Heat Shield

Each component is described briefly, indicating what its function is. For example, the text for Descent Stage:

• "The descent stage is the rover's free-flying 'jetpack,' which separates from the backshell and uses eight engines to slow the final descent. It also contains the landing radar system used to make last-minute decisions about touchdown. Just before touchdown, the descent stage lowers the rover on cables before gently placing it on the surface. Once the rover is on the ground, the descent stage flies off to make its own uncontrolled landing on the surface, a safe distance away from the rover."

This page has a further link to the Rover, which is the component that my students are most interested in: https://mars.nasa.gov/mars2020/spacecraft/rover/

The page downloads a 3D model of the Rover on which it's possible to zoom in, rotate, and mouse over each component to get a closer look and more information. The written information underneath the model compares the components to body parts enabling the rover to function for survival. It is a very good example of using comparisons that a non-technical audience would understand:

• "It is car-sized, about 10 feet long (not including the arm), 9 feet wide, and 7 feet tall (about 3 meters long, 2.7 meters wide, and 2.2 meters tall). But at 2,260 pounds (1,025 kilograms), it weighs less than a compact car. In some sense, the rover parts are similar to what any living creature would need to keep it 'alive' and able to explore."

This comparison is continued in the brief description of the purpose of each part:

• body: a structure that protects the rover's "vital organs"
• brains: computers to process information
• temperature controls: internal heaters, a layer of insulation, and more
• "neck and head": a mast for the cameras to give the rover a human-scale view
• eyes and ears: cameras and instruments that give the rover information about its environment
• arm and "hand": a way to extend its reach and collect rock samples for study
• wheels and legs: parts for mobility
• electrical power: batteries and power
• communications: antennas for "speaking" and "listening"

Clicking on each of the parts brings you to a separate page with more information about that particular part.

Finally, a further resource is a Landing Toolkit for educators: https://mars.nasa.gov/mars2020/timeline/landing/

Much of the information was for use before the landing, but there are many more materials, and links with ideas for how to use them.

Five unusual technologies for water

An article written by Manzoor Qadir and Vladimir Smakhtin, Assistant Director and Director, respectively, of the Institute for Water, Environment and Health, United Nations University, reports 5 possible technologies for harvesting water in water-scarce areas of the world. There isn't much specific information about the technologies themselves, but the short description of each of the technologies includes a link to a scientific paper describing that process. These are probably too academic for many students, but the abstracts and conclusions give an overview of the information.

Link to the article: https://theconversation.com/five-unusual-technologies-for-harvesting-water-in-dry-areas-154031

The 5 technologies, with part of their description from the article, are:

• Catching fog: Fog can be collected using a vertical mesh that intercepts the droplet stream. This water then runs down into a water collection, storage and distribution system.
• Cloud seeding: This technology involves dispersing small particles into clouds or in their vicinity. These particles act as a starting point for raindrops or ice crystals, promoting their formation. In turn, this makes it more likely to rain or snow.
• Minimising evaporation: There are two major types of micro-catchment rainwater harvesting systems. One is water harvesting via rooftop systems where runoff is collected and stored in tanks or similar devices. This water is used domestically or for livestock watering. The second is water harvesting for agriculture, which involves collecting the rainwater that runs off a catchment area in a small reservoir or in the root zone of a cultivated area.
• Desalinating seawater: The process of desalination removes salt from seawater or brackish groundwater to make them drinkable.
• Iceberg harvesting: Moving an iceberg across the ocean is technically possible, based on a theoretical four-part process. It would require locating a suitable source and supply, calculating the necessary towing power requirements, accurately predicting melting in transit, and estimating the economic feasibility of the entire endeavour.

Students could discuss the pros and cons of each technology, rating them according to different factors; for example: practicality, impact, economy, timeframe, region, etc.

The first sentence of the article is: "Water scarcity is among the top five global risks affecting people's wellbeing." Students could brainstorm what they think the other four global risks are. The risks are divided into two types: risks in terms of likelihood and risks in terms of impact. So students could also rate their ideas according to those factors. The sentence contains a link to the World Economic Forum Global Risk Report 2020, so their answers can be compared to the list in the report. This is from that report:

The Top 5 Global Risks in Terms of Likelihood:

• Extreme weather
• Climate action failure
• Natural disasters
• Biodiversity loss
• Human-made environmental disasters

The Top 5 Global Risks in Terms of Impact:

• Climate action failure
• Weapons of mass destruction
• Biodiversity loss
• Extreme weather
• Water crises

For the longer lists of global risks, in terms of likelihood and impact, here is the link to the entire report: http://www3.weforum.org/docs/WEF_Global_Risk_Report_2020.pdf

Since the article focuses on water issues, there is of course useful vocabulary for this field of study. The words and phrases can be focused on according to category, as I have listed them below, or noted in terms of word form (eg, noun vs verb: runoff - runs off; noun vs adjective: water scarcity - water-scarce areas).

Types of water:

• cloud water
• desalinated water
• drinking water
• droplet stream
• drought
• freshwater
• fog
• groundwater
• iceberg
• municipal water supply
• precipitation
• polar ice caps
• rainfall
• runoff
• seawater
• water embedded in fog
• water resources
• water-scarce area

Water verbs:

• absorbing (water)
• dispersing (small particles)
• evaporate
• melting
• runs off
• (resources can be) tapped

Technical terms:

• catchment
• desalination
• micro-catchment
• rain enhancement
• water cycle
• water harvesting
• water insecurity factors
• water scarcity
• water shortages

If students do further work learning about any of these technologies and want to talk or write about them, then this vocabulary will certainly come in useful.

Podcast: Why go to the moon?

In my last post (8 February: SpaceX vs Nasa to the moon), I wrote about an article comparing which rocket is most likely to get humans to the moon again. This post considers why humans want to go to the moon at all.

There is a podcast series of 5 episodes on the conversation website, called To the Moon and Beyond. Episode 4 is "What's the point of going back to the moon?" The podcast series was made in 2019, but the issues raised are still relevant.

Link to podcast 4: https://theconversation.com/to-the-moon-and-beyond-4-whats-the-point-of-going-back-to-the-moon-120791

The short article accompanying the podcast gives an overview of the topics discussed and describes the episode:

• "In the fourth episode of The Conversation's To the moon and beyond podcast, we delve into why there's a renewed drive to put humans back on the surface of the moon. What's there to go back for? And what are the practical, legal and ethical questions facing those who want to set up a base there -- and potentially start mining the moon?"

The two hosts are Miriam Frankel (Science Editor at The Conversation) and Martin Archer (Space Plasma Physicist, Queen Mary University of London). The 5 scientists they interview are:

• Frans von der Dunk, Professor of Space Law, University of Nebraska-Lincoln
• Fréderic Marin, Chargé de recherche (CNRS) à l'Observatoire Astronomique de Strasbourg, Université de Strasbourg
• Katherine Joy, Royal Society University Research Fellow/Reader, School of Earth and Environmental Sciences, University of Manchester
• Rowena Christiansen, Medical Education Tutor, Doctor and Researcher, University of Melbourne
• Tanja Masson-Zwaan, Assistant Professor of Space Law at Leiden University in The Netherlands

The podcast lasts 35:58 minues, so it might be rather long for some students. All interviewees speak clearly, but there are a variety of accents (both English and non-native speaker) and various speaking tempos. However, students could listen to the podcast at home, so they can repeat as necessary or listen in shorter time sections.

The topics discussed include:

• Which resources could potentially be found on the moon and which problems would there be with extraction;
• Which laws exist, and which should be made, that govern who can mine lunar resources and how ownership would be determined;
• The ethics involved in the abilities of different countries to travel to the moon;
• The physical and psychological effects of being in low gravity, with extremely long days and nights;
• Ways in which people could survive sustainably on the moon.

Unfortunately, there is no transcript available. If listening to the entire podcast for an assignment or task is too difficult for some groups, then the teacher could "divide" the podcast into separate sections, each one covering a different topic area. Then each student, or small groups, could be assigned a specific section to listen to and write a summary of the information, which could be made available to their colleagues. This way, each student would have an overview of the entire podcast.

If the topic of "to the moon and beyond" is interesting for the group, then students might want to choose another podcast in the series (each one is 30 to 34 minutes):

• 1: What we learned from landing on the moon and why we stopped going
• 2: How humanity reacted to the moon landing and why it led to conspiracy theories
• 3: The new space race and what winning it looks like
• 5: What space exploration will look like in 2069

Link to the series overview: https://theconversation.com/uk/podcasts/moon-and-beyond

SpaceX vs Nasa to the moon

A recent article on the website 'the conversation' compares and contrasts two rockets being developed for space travel: SpaceX vs Nasa: who will get us to the Moon first? Here's how their latest rockets compare, by Gareth Dorrian (Post Doctoral Research Fellow in Space Science, University of Birmingham) and Ian Whittaker (Senior Lecturer in Physics, Nottingham Trent University). Accompanying image is from the article.

Link to article: https://theconversation.com/spacex-vs-nasa-who-will-get-us-to-the-moon-first-heres-how-their-latest-rockets-compare-154199

The first part of the article gives background information about rockets, and then describes first the SpaceX Starship and then Nasa's Space Launch System (SLS). From this information, students could look into the relative advantages and disadvantages further. For example, SpaceX's launch vehicle burns a combination of liquid methane and liquid oxygen, while NASA's SLS core stage contains liquid hydrogen and liquid oxyen.

"The [SpaceX launch vehicle's] rocket will provide 15 million pounds of thrust at launch" vs. Nasa: "The core stage of the rocket is augmented by two solid rocket boosters, attached to its sides, providing a total combined thrust of 8.2 million pounds at launch."

The final paragraph sums up the pros and cons of each:

"Ultimately it is a competition between an agency that has had years of testing and experience but is limited by a fluctuating taxpayer budget and administration policy changes, and a company relatively new to the game but which has already launched 109 Falcon 9 rockets with a 98% success rate and has a dedicated long-term cash flow."

Students could first compare their first impressions of the two approaches, and then gather information to support one or the other. In a classroom setting, a debate could be organized (SpaceX or Nasa?). In a distance-learning situation, students could submit their "argument" supporting the one they think will be the 'winner' and why. Fellow students with an opposing view could choose one to read and comment on.

Throughout the semester, students can follow updates about the two rockets since both SpaceX and Nasa are often in the news and on many scientific/technical websites. Areas to focus on are not only each rocket's advantages and disadvantages, but also the differences in innovation development between a private firm and a government agency.

The article has relevant examples of language used to compare and contrast. For example:

• but X is also
• both X and Y are developing
• which is approximately twice as much as
• X and Y are both
• their main difference from X is that
• about 5% more than
• which is smaller and lighter than
• a task that current Xs are currently not capable of performing
• so there is a higher cost with X, both in materials and environmentally
• which is potentially more than
• whereas

There are also examples of the tenses that my students find most difficult to use.

Examples of the present perfect tense (which has no reference to a point of time in the past):

• No-one has visited the Moon since 1972.
• Nasa has selected the private company SpaceX to be part of its commercial spaceflight operations
• Musk has also stated that a crewed Martian mission could take place as early as 2024
• Ultimately it is a competition between an agency that has had years of testing and experience
• a company relatively new to the game but which has already launched 109 Falcon 9 rockets

Contrasted with simple past tense, with related past time reference underlined:

• A recent test flight of the Starship prototype, the SN8, successfully demonstrated ... Unfortunately there was a malfunction in one of the Raptor engines and the SN8 crashed on landing.
• three of which were used on the previous Space Shuttle
• a test fire of the SLS core stage was stopped a minute into the eight-minute test

There are many examples of the use of the simple present tense to indicate "something that is true in the present; that happens regularly in the present; that is always true" (according to the British Council website https://learnenglish.britishcouncil.org/english-grammar-reference/present-simple) -- Rockets go through multiple stages to get into orbit; the rocket becomes lighter; the Starship flips into a vertical position and uses its on-board Raptor engines; etc.

But my students find it more difficult to decide when to use the present progressive tense. So the examples from the article are very useful as illustrations of something happening currently:

• the firm is also pursuing its own space exploration agenda
• both Nasa and SpaceX are developing new heavy lift rockets
• The spacecraft is maturing rapidly
• a task that current Nasa rockets are currently not capable of performing
• "I don't think we're looking at a significant design change."
• they are running #dearMoon - a project involving lunar space tourism

Finally, since the article includes information about planned future developments, there is the use of the future tense with "will": SpaceX's launch system will be comprised of two stages; the rocket will provide; it will have sufficient thrust; this will lift the spacecraft; etc. But the future is also referred to with the simple present tense and with phrases useful for students to learn:

• The upper stage is intended to lift the attached payload
• The core stage and booster rockets are unlikely to be reusable
• It is designed to evolve to larger stages
• which is potentially more than Starship
• Artemis 2 is planned as the first crewed mission
• and is expected to launch in August 2023
• a crewed Martian mission could take place as early as 2024

The article ends with the sentence: "Whoever reaches the Moon first will inaugurate a new era of exploration of a world which still has much scientific value." This alone could provide much discussion or response: Who is likely to "reach the Moon first"; what the impact could be of "who" the first would be; what a "new era" would look like; what aspects of "exploration" would be the most useful or least harmful; and what examples of "scientific value" would be generated.

Bonus: The article's website has a 2:21-minute film clip of the Starship SN8 High-altitude flight re-cap. There is no narration except for the voice counting liftoff, but the stages are labeled on the screen. There is also a labeled diagram of the stages of Nasa's SLS as well as the illustration comparing rockets that I have used for this post.

Explaining with comparison

 A timely article on the website engineering.com is an excellent example of a way to explain a complicated idea to a non-specialist audience: How One Virologist is Using Cheese to Explain Covid-19. The title itself caught my attention, and I challenged my students to think of ways that cheese could be used this way before reading the article (they couldn't, but neither could I). 

Link to article: https://www.engineering.com/story/how-one-virologist-is-using-cheese-to-explain-covid-19

In this blog, I've referred to using examples in texts to raise students' awareness of how to focus on audience when they write or present. One of the ways to explain a concept is to use comparisons to something the audience already knows. In this article, the comparison uses the example of stacked slices of Swiss cheese (a cheese with holes).

The article relates an idea of Ian M. Mackay, a virologist at the University of Queensland, who uses the example of Swiss cheese to explain why one defense alone against the Covid-19 virus is not effective, but that a variety of methods are:

    "Imagine multiple Swiss cheese slices with their holes and all, each lined up one after the other. When the cheese is stacked, it is hard to see what's on the other side. However, when you take some slices out of the stack, it becomes more visible. When applying this analogy to the COVID-19 pandemic, the layers can signify social distancing, masks, hand-washing, refraining from touching your face, avoiding crowded areas, testing and tracing, ventilation, government messaging, quarantines, and vaccines."

The infographic above shows the idea, and is from Mackay's twitter account (pic.twitter.com/nNwLWZTWOL).

As stated in the article, "The model aims to explain that there is no single intervention that can be the answer to solve the virus, as each layer has its holes or faults. Instead, society should adopt multiple methods to stop transmission of the virus."

The idea is related to the Swiss Cheese Model of Accident Causation, which comes from psychologist James T. Reason (in his book Human Error) and is said to "explain many disasters from the space shuttle Challenger Shuttle (sic) explosion to the Bhopal disaster, and the Chernobyl nuclear accident." In Reason's model, the slices of cheese are lined up so that the holes are in a straight line, leading to the buildup of the accident. The article has an image of Reason's model as well.

Engineering students can use the examples in this article to think of their own ways to explain a technical concept from their studies or work to a layperson. Particularly useful is the concept of analogy, which many of my students often have a difficult time understanding. Not only is there the analogy of aligned slices of Swiss cheese to explain how multiple actions provide a better defense against the virus, but there is also a quote from James T. Reason giving an analogy that compares active failures to mosquitoes:

    "Active failures are like mosquitoes. They can be swatted one by one, but they will still keep coming. The best remedies are to create more effective defenses and to drain the swamps in which they breed. The swamps, in this case, are the ever-present latent conditions."

The explanations themselves provide a template for students' writing or presentations:

• Imagine ____
• When applying this analogy to ____
• the ____ can signify ____
• ____ are like ____
• The ____, in this case, are ____

The article ends with: "This model is not widely accepted without its share of criticism due to its limitations in understanding the full scope of the pandemic; however, it can guide society toward a better understanding of the risks and tools to combat the virus in these unprecedented times."

In the same way, this example alone might not be enough to help students come up with their own ideas; however, it can guide them toward a better understanding of how comparisons can be used to explain technical information to a non-technical audience.

A Bonus: Students can listen to the article being read by a male voice with an American accent by clicking Listen to Story at the top of the page. The recording is 5:21 minutes.

SpaceX's car in space

Image: Elon Musk/SpaceX via Instagram

This month SpaceX, Elon Musk's company, launched its Falcon Heavy rocket successfully, which is big enough news to discuss with my students. However, making it even more interesting is that the rocket launched a car into space. The car is a Tesla Roadster and it has a "starman" sitting in the driver's seat.

This topic is interesting for my engineering students for a number of reasons. First, they find Elon Musk to be an interesting entrepreneur and innovator - young, dynamic and not tainted by a bad corporate image. Then, this is about rockets, space, technology and cars - all things my students like to learn about. And this idea seems a bit crazy, unconventional. Finally, there are many implications for the future of the technology used and the successful launch of a non-government rocket. 

There are many articles on all sorts of websites about the successful launch of SpaceX’s Falcon Heavy rocket. The one I have chosen is written in a fairly conversational register, but also has useful technical vocabulary and collocations.

The article is from The Guardian, titled SpaceX oddity: how Elon Musk sent a car towards Mars. The subheading is, "A Starman sitting in a tin can is currently navigating the heavens, soundtracked by David Bowie. How did it -- and we -- get there?

Link:  https://www.theguardian.com/science/2018/feb/07/space-oddity-elon-musk-spacex-car-mars-falcon-heavy 

In addition to the article, there are two further links; one to a video (1:37) "watch the launch of the Falcon Heavy rocket"; and to a graphic showing the path of the Falcon Heavy rocket (which is useful for description). 

The language material that seems useful is also related to description: adjectives, descriptive phrases, and expressions.

Since it is describing the sequence of events, there are also useful phrases of time:

• now the most powerful rocket
• during the Apollo era
• on Tuesday
• on launch day
• delayed for over three hours
• minutes before countdown
• (don't clap) until you see
• in the end
• moments later
• after that
• not seen since the 60s
• before liftoff
• when (mission CRS-7) was lost
• for more than a year
• last February
• as soon as this year
• in the meantime

Students can not only notice these phrases, but consider how they could be put in order so that they can relate the events differently.

For relating the information, students can also notice useful collocations, such as:

• navigating the heavens
• (be) at the wheel
• beam down
• imprinted on (the circuit board)
• in orbit around
• music playing on (the speakers)
• (high-energy radiation belts that) circuit Earth
• projected path
• crash into (the planet)
• stay on course
• drift through space
• forcing (it) to close
• propel into orbit

Finally, there is material for discussion about the future impact of this launch. Elon Musk is quoted in the article as saying,

• "If we are successful, it's game over for other operators of heavy-lift rockets." 

He goes on to explain:

• “It’s like where one aircraft company has reusable aircraft and all the other aircraft companies had aircraft that were single-use, and you’d sort of parachute out at your destination and the plane would crash land somewhere. Crazy as it sounds, that’s how the rocket business works.”

And the article concludes with the observation:

• "The Falcon Heavy's successful launch propels the dream into a new orbit. Plans include building a new space station above the moon, carrying new telecom or spy satellites, and shuttling people to deep space destinations."

Students could have a lot of ideas about the impacts of these changes.