ALL POSTS
Real, live scientists sharing cutting-edge research and related classroom activities.
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Developing materials that more efficiently convert solar energy to electrical energy is a major research goal of condensed matter physicists. But how do solar panels work?
Neutrons for Nanoscience!
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!
New World Disorder
We tend to think of materials as either electrical conductors or insulators: some materials, like metals, have low electrical resistance and conduct electricity easily, while others, like wood or plastic, have high electrical resistance and do not readily conduct electricity. Strange experimental results, however, reveal large fluctuations in the electrical resistance of thin metallic nanowires when a magnetic field or charge difference is applied to them. Click to learn how a more nuanced understanding of electron behavior helps to explain these variations in electrical resistance that may revolutionize the tech industry!
Physics Wonder Girls!
Research shows that, among girls, interest in science is most likely to wane during the middle school years. Our Physics Wonder Girls Camp provides three days of physics-based experiments, fun demonstrations, and contact with women scientists to plant and sustain middle-school girls' interest in science in general, and physics in particular.
Plot Twist! The Science of Oreology
You take a pristine-looking Oreo from a package of seemingly identical sandwich cookies, and you decide to open it up to eat the creme filling first. You gently twist the cookie apart without breaking the chocolate wafers, but the creme sticks to one side only. Why? Happily, the physics of fluids helped two MIT students solve this delicious mystery. Read on to find out what they learned, and how you can test their results at home.
Quasiparticles and ‘Weyltronics’
Scientists have finally discovered massless particles, and they could revolutionize electronics.
Scanning Tunneling Microscopy
You’re lining up your phone to take a picture of your dog. Light comes down from the sun, bounces off the dog, and into your camera lens, allowing you to take the photo. Your eyes work similarly, taking in all the light particles, known as photons, that are scattering off of objects in the world. Most things “see” by detecting these bouncing photons, which is why both you and your phone have a hard time seeing anything at all when the lights are off.
Spin cant? Spin CAN!
In most magnetic materials, the magnetic moments of individual atoms are aligned parallel to one another and point in the same direction. In special structures called skyrmions and antiskyrmions, however, they are arranged in a spiraling pattern. Their stability and compact size makes skyrmions and antiskyrmions especially useful for encoding lots of data in a small space. But a few questions need to be answered before skyrmion-based technology can be used in your iPhone or other memory devices. First, why do these magnetic structures form in some materials and not others? How can we design a system where they will form? And how can we generate these structures on demand? Click to find out!
Spins and Skyrmions
Recent progress in materials science has led to the creation of new magnetic materials in which the magnetism follows complex patterns. The formation of these patterns depends on a phenomenon called spin-orbital coupling. Because they can be manipulated by electric currents and temperature changes, materials exhibiting these interesting magnetic patterns may have applications in magnetic memories and logic devices. Click to learn how!
Squeezing and Stretching Nanomaterials
Squeezing and stretching materials only a few atoms thick can result in dramatic changes.
Straining for More Stable Memory
Would you rather have data storage that is compact or reliable? Both, of course! Digital electronic devices like hard drives rely on magnetic memory to store data, encoding information as “0”s and “1”s that correspond to the direction of the magnetic moment, or spin, of atoms in individual bits of material. For magnetic memory to work, the magnetization should not change until the data is erased or rewritten. Unfortunately, some magnetic materials that are promising for high density storage have low data stability, which can be improved by squeezing or stretching the crystal structures of magnetic memory materials, enhancing a material property called magnetic anisotropy.
Superfluid helium and black holes
At low temperatures, helium—the same substance that makes balloons float—becomes a special type of liquid known as a superfluid, which has zero viscosity. It's like the anti-molasses! The properties of superfluids are governed by the laws of quantum mechanics. More specifically, the atoms in superfluid helium are “entangled” with each other, allowing them to share information and influence each other’s behavior in ways that are totally foreign to our everyday experience, and which Einstein famously described as "spooky action at a distance." Better still, scientists have recently discovered that the law controlling entanglement between different parts of a helium superfluid is the same as that governing the exotic behavior of black holes in outer space.
Superpowers of Liquid Crystals
It's a solid . . . it's a liquid . . . it's a LIQUID CRYSTAL! Researchers at the University of Wisconsin-Madison Materials Research Science and Engineering Center are investigating how the unique properties of liquid crystals allow them to act as environmental sensors, detecting toxins in the environment. In this video, we give a brief overview of what liquid crystals are and how their properties can be utilized to improve the world.
The Adventures of Solar Neutrons
Neutron radiation detection is an important issue for the space program, satellite communications, and national defense. But since neutrons have no electric charge, they can pass through many kinds of solid objects without stopping. This makes it difficult to build devices to detect them, so we need special materials that can absorb neutrons and leave a measurable signature when they do. Researchers at the University of Nebraska-Lincoln are studying the effects of solar neutron radiation on two types of materials on the International Space Station (ISS), using detectors made of very stable compounds that contain boron-10 and lithium-6.
The Future is Flat
Welcome to the fascinating world of two-dimensional (2D) materials! Today, we're going to explore a novel 2D material created by boiling off atoms, which we guide to form large crystalline flakes that will become the filling in tiny magnetic sandwiches. Intrigued? Click to learn more!
The future of solar energy is . . . an inkjet printer?!
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.
The Shape of the Future
There are many ways atoms can arrange microscopically to form crystalline materials. Interestingly, materials created from different arrangements of the same atoms may exhibit completely different physical and chemical properties. A method called thin film epitaxy allows scientists not only to fine-tune the properties of known materials, but also to generate completely new materials with structures and properties not found in nature.
This photon walks into a crystal . . .
When light strikes a material, electrons may be ejected from the material. This is called the photoelectric effect, and it’s the basis for many different technologies that convert light energy into electrical energy to generate current. In addition, the photoelectric effect is useful to scientists studying novel materials.
Unit Cells and Their Molecular Building Blocks
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!
Use a laser pointer to measure the thickness of your hair!
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!
Use Light to Turn Your World Upside-Down!
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.