Introduction and Outline

I'm working on text today, so you'll see it come in during the day if you're checking in. Until then, please watch the video in Section 15.5 and complete the exercise.

Every material has its use, and using materials has a wide variety of impacts. In this chapter we'll consider these broader impacts (bother positive and negative) of materials on the economy, the environment, and society at large. Below, we'll outline a few general examples, and then we'll focus on economic and environmental impacts in particular in the following sections.

Material Impacts on Society

I cannot think of a single aspect of society that is not impacted by materials. Materials are a main driver in societal change, foster positive, negative, and neutral changes in human social behavior. The list of impacts that materials have on society is inexhaustible, so I gave myself a half and hour to enumerate some of them - I decided on Sport, Art, and Gaming, but you can choose anything of course and find your own impacts Exercise 15.2.1. You might consider consumerism, travel, language, traditions/culture, religion/spirituality, social interaction (i.e., cell phones and their impact), education, law/justice, civil rights, public health. Anything! There's a material that has an impact.

Sport

Pick your favorite sport - it does matter what it is - and look at its history. Undoubtedly materials have affected the game in some way. One of my favorite examples of this is the World Record progressions in swimming, cross-referenced with new technology (which of course are enabled by materials.

In Fig. Figure 15.2.1, we see the number of world records broken in swimming each year since 1956. Three of the top five record-setting years align with the introduction of a new, material-enabled technology. In 1967 it was touch pads, which eliminated systematic visual delays in timing from judges and eliminated timing controversies. These touch pads were made of electronic pressure sensors (two plates/meshes that created an electrical signal when they contacted) surrounded by a water- and chemical-proof synthetic rubber pad. Without these materials (and the nice design from electrical engineers and others), we'd still be using stopwatches and our swimmers would be "slower".

In the 1960s few swimmers wore goggles, but if they did, they were bulky and made of thin glass. There was no silicone to seal the goggle against the eye, and they were tied on with string. However, in the 1970s the goggle wen through a design revolution with elastic straps, rubber eye seals, and polycarbonate lenses. Swimmers could now see clearly underwater, improving orientation and allowing swimmers to focus on swimming form. They may have even been able to train longer since they no longer had annoying chlorine eye! Over 20 World Records fell that year.

Then - and perhaps the most conspicuous - was in 2008. There were some good swimmers that year, of course, but much of the attention was on the full-body LZR Racer Suit. Just in March of 2008, 13 World Records fell. This suit was designed to improve hydrodynamics with a elastane-nylon surface to reduce skin friction, but also incorporated foamed polyurethane to trap air for bouyancy. In 2008 and 2009 over 30 world records were broken before the suit was nerfed on Jan. 1 2010.

Art

Art media are ever-changing, and new materials enable artists to explore new artistic forms. Some of you were able to participate in the MAT_SCI 302 Laboratory where we made jewelry out of metals clays - that's one example. Historical examples include glasswork, bronze and plastics for sculpture, and photosensitive technologies for photography.

I'll highlight the first color photographic technology: Autochrome Lumière. This technology was the first to utilize dyed filter layers - materials that absorbed specific wavelengths of light and let others pass - and silver halide (and interesting material in its own right). In the case of Autochrome Lumière the filter was very simple: the natural material of potato starch, dyed with yellow, green and red. These starch particles were processed to be about 10 um in size, which provided some resolution, and were protected from moisture with shellac. The tone of the final images were dark (Fig. Figure 15.2.2), which gives these early 20th century photographs a ""vintage" look

Gaming

The online gaming industry is massive, producing around $200 billion dollars in revenue a year. The industry is also global, and an important draw of gaming is that you can play with anyone in the world with an internet connection, anytime you want. The ability to do this has created an entire international gaming culture.

Every time you play a online game with a friend, you're communicating with them. This communication is nearly fully dependent on the world's submarine optical cable networks (99% of all international data goes through this system). In turn, this network is fully dependent on an important device developed in earnest in the 1980s: the fiber optical cable. At the "core" of this important device is the glass fiber that enables the technology.

The glass is made from ultra-pure silica $\ce{SiO2}$ which transfers the light-based communication with minimal loss. It is inert and does not absorb water. It is cheap. It can be doped to change its refractive index as necessary. It probably won't suprise you, but American company Corning was behind the glass technology that enabled the fiber-optic communication explosion.

This technology has changed how people game. When I was a kid, it was Sega in a basement with friends - this was before the internet came to my small rural town in Wisconsin. In the late 90s broadband internet access was still inaccessible for many, but people still wanted to socialize and play games, so the LAN party was born. Nowadays, you can use the world's fiber optic network to play games in your room, with the lights off, wearing a headset by yourself... a very distinct social experience from those of even 20 or 30 years ago with both positive (friends from anywhere!) and negative (no eye contact) social impacts.

Outline

• Section 15.3, Materials Scarcity, Demand, and Consumption: The supply and demand for materials influences their utility. In this section we'll discuss the historical and future consumption of materials and some factors that influence their scarcity.
• Section 15.4, Materials' Environmental Impact: In this section we'll outline the ways that materials can impact the environment, which are multi-faceted and ever-changing.
• Section 15.5, Life-cycle Analysis: To make good decisions about which materials to use if we are to reduce their impact on the environment, we must understand the different stages of a materials life-cycle, from "birth" (extraction and processing) to "death" (disposal or recycling).
• Section 15.6, Recycling: One option for a materials "end-of-life" is recycling. While the question of whether to recycle a material depends on economics, extend of environmental impact, societal impact of disposal, but the process of recycling is pure materials science and engineering!

Outcomes

By the end of this module, students should be able to:

• Assess and infer (broadly) the role of materials in affecting society, the environment, and the economy.
• Identify the phases of the materials life cycle, and analyze positive/negative inputs/outputs during the materials life cycle.
• Evaluate factors that limit efficiency during materials production.
• Assess (broadly) the impacts of materials production, product fabrication, product use, and materials disposal on society, the economy, and the environment.
• Evaluate materials structure and properties within the context of recycling.
• Perform basic energy evaluations to inform decision-making in materials selection and usage.