Students make paper models of crystal unit cells and build a large crystal structure together while reflecting on the role of symmetry in crystal formation. This lesson is part 3 of a 4-part student-driven, lecture-free series, in which students will do card sorts, build hands-on models, solve engineering design puzzles, and more!
Crystals aren't magic, but they are amazing! In this engaging, comic-driven lesson, students do individual and group-based activities to understand the characteristics of crystals (like quartz) versus amorphous solids (like glass). This lesson is part 1 of a 4-part student-driven, lecture-free series in which students will do card sorts, build hands-on models, solve engineering design puzzles, and more!
Through hands-on activities using gumdrops and toothpicks, students will learn about unit cells that make up the repeating structures of crystals like table salt. This lesson is part 2 of a 4-part student-driven, lecture-free series, in which students will do card sorts, build hands-on models, solve engineering design puzzles, and more!
Students learn how some crystals produce electricity when squeezed! This lesson is part 4 of a 4-part student-driven, lecture-free series, in which students will do card sorts, build hands-on models, solve engineering design puzzles, and more!
Scientists are working to develop electronic devices that store and process information by manipulating a property of electrons called spin—a research area aptly known as spintronics. The semiconductors we are developing will not only be faster and cheaper than those used in conventional devices, but will also have more functionality.
When we examine the world around us, we observe its structure, or where things are, as well as its dynamics, or how things move and interact. Likewise, when we investigate a new material, we want to understand its structure and dynamics—where the atoms and molecules are, and what they are doing. To do this, we need measurement techniques that can tell us what is happening at a very small scale. Read on to find out how neutrons come to our rescue!
Have you ever wondered why some materials are hard and others soft, some conduct heat or electricity easily while others don't, some are transparent to light while others are opaque . . . and on and on and on? The material universe is vast and diverse, and while a material's properties depend in part on the elements it is made from, its structure—how it is built from its constituent atoms—can also have wide-ranging effects on how it looks, feels, and behaves. Diffraction is a method that allows us to "see" the atomic structure of materials. Read on to find out how it works!
Inside solids, the properties of photons can be altered in ways that create a kind of "artificial gravity" that affects light. Researchers at the University of Pittsburgh tracked photons with a streak camera and found that whey they enter a solid-state structure, they act just like a ball being thrown in the air: they slow down as they move up, come to a momentary stop, and fall back the other way. Studying this "slow reflection" will allow us to manipulate light's behavior, including its speed and direction, with potential applications in telecommunications and quantum computing technologies.
In phase-change memory (PCM), nanoscale volumes of a special kind of glass compound are heated by very short electrical pulses, causing the atomic structure of the material to switch between an ordered phase and a disordered phase. These phase-change materials have been used for years to store data on rewritable CDs and DVDs, but until recently, the large energy required to change the state of the material has made it impractical for electronic memory. If this challenge can be overcome, phase-change memory can be integrated with conventional silicon electronics for high-capacity data storage and more efficient computation. Click to read more about how we are working to make this new technology a reality!
Very small structures, much smaller than the human eye can see, often fall in the size range of nanometers. By understanding how the molecules that make up these structures interact, we can engineer them to do many special things that cannot be done at a larger scale. One exciting structure is a polymer brush, in which long, chain-like molecules called polymers are tethered at one end to a surface and stick up from the surface like bristles on a hairbrush. Polymer brushes can be used to keep bacteria away, provide an exceptionally smooth surface for items to slide across, or trap other molecules in solution like a hairbrush traps loose hair. In order to engineer polymer brushes that will perform as desired for a given application, we must understand the physics of how the molecular bristles move, and the chemistry of how they interact with their environment.
To increase our use of solar energy, we need to create more efficient, stable, and cost-effective solar cells. What if we could use an inkjet printer to fabricate them? A new type of solar cell uses a class of materials called perovskites, which have a special crystal structure that interacts with light in a way that produces an electric voltage. We've developed a method to produce perovskite thin films using an inket printer, which in the future could pave the way to manufacture solar cells that are surprisingly simple and cheap.
Have you ever wondered how scientists can accurately measure the size of very small objects like molecules, nanoparticles, and parts of cells? Scientists are continually finding new ways to do this, and one powerful tool they use is light scattering. When an incoming beam of light hits an object, the light "scatters," or breaks into separate streams that form different patterns depending on the size of the object. This incoming light might be visible light, like the light we see from the sun, or it might be higher-energy light like X-rays. The light from commercial laser pointers, it turns out, is perfectly suited to measure the size of a human hair!
AtomTouch is a free, interactive molecular simulation app, created by researchers at the University of Wisconsin Materials Research Science and Engineering Center (UW MRSEC) to allow learners to explore principles of thermodynamics and molecular dynamics in an tactile, engaging way.
Self-assembly is the process by which individual building blocks—at the smallest level, atoms—spontaneously form larger structures. The structures they form depend on the size and shape of the building blocks, and on the conditions to which these building blocks are exposed. This can be demonstrated quite simply using breakfast cereal, or for more complex cases using specially prepared Legos.
Solids are generally divided into metals, which conduct electricity, and insulators, which do not. Some oxides straddle this boundary, however: a material's structure and properties suggest it should be a metal, but it sometimes behaves as an insulator. Researchers at the University of California, Santa Barbara are digging into the mechanisms of this transformation and are aiming to harness it for use in novel electronic devices.
Graphene is a two-dimensional material made from a single sheet of atoms, with outstanding mechanical, electronic, and thermal properties. It is a promising candidate to enable next-generation technologies in a wide range of fields, including electronics, energy, and medicine. This economical, safe, and simple lab activity allows students to make graphene via chemical vapor deposition in 30–45 minutes in a classroom setting.
Many solid materials have a crystal structure, with atoms that exist in a particular, organized arrangement. The degree of organization can vary among crystals, however. High-quality crystalline materials are the foundation of many familiar devices, such as integrated circuits and solar cells. A better understanding of these materials and how to produce them is important for developing new technologies.
We can easily observe light with our eyes, and so it is one of the most familiar parts of the world around us. And yet, light often does amazing and unexpected things. Light travels in straight lines from the source to our eyes. This fact allows us to understand many of the cool things that light can do. In this lesson, we will observe how light creates mirages and shadows. And we will build a pinhole camera which makes things appear upside-down. We can understand the upside-down images by thinking about the straight line that the light took from the object to the screen.
Magnets curve themselves into beautiful patterns called domains, which cannot be seen with the naked eye. Now that magnetic paint and nail polish are easily available, we can use magnets to create all kinds of magnetic patterns which we can see, photograph, erase and rewrite! Click to find out how YOU can paint with magnets!