Fields & matter

Ising Critical Fluctuations

Why do large patches of aligned spins appear near a critical temperature?

12 min

Fields & matter

Hopfield Associative Memory

How can a network recover a whole picture from a damaged cue?

12 min

Fields & matter

Climate Energy Balance

Why does Earth keep warming after the heating stops increasing?

12 min

Fields & matter

Alfvén Waves

How can a magnetic field carry a sideways disturbance through a plasma?

12 min

Fields & matter

Transistor Bias and Output Curves

Why does the collector current stop following the base current at low output voltage?

15 min

Fields & matter

Heterojunction Injection

How do a band step, bias and temperature change carrier injection?

15 min

Fields & matter

Blue LED: Recombination and Efficiency

Why can a blue LED become brighter while its efficiency falls?

15 min

Fields & matter

CCD: Follow the Charge

Why does a bright CCD pixel leave a trail when charge transfer is imperfect?

16 min

Fields & matter

GMR Spin Valve

How does rotating one magnetic layer change the resistance of a spin valve?

16 min

Fields & matter

Neutron Triple-Axis Spectrometer

What does a neutron’s final energy tell us about motion inside a sample?

20 min

Fields & matter

Solar Neutrino Flavor Observatory

How can you tell a fainter Sun from neutrinos that change flavor on the way?

25 min

Fields & matter

Long-Baseline CP Observatory

Can the neutrino and antineutrino spectra from an accelerator beam reveal the CP phase?

30 min

Fields & matter

Neutrino Sky Search Observatory

Does a neutrino hotspot found by scanning the whole sky count as real evidence?

25 min

Fields & matter

Beta Energy Sharing Observatory

Why do electrons from beta decay come out with a whole range of energies?

25 min

Fields & matter

Double Beta Decay Observatory

In double beta decay, what would a peak in the two electrons’ total energy mean, and what if none appears?

25 min

Fields & matter

Beta Endpoint Mass Observatory

How can electron energies near the end of the beta-decay spectrum reveal the neutrino’s mass?

25 min

Fields & matter

Reactor Near–Far Spectra

How can detectors near and far from a reactor reveal neutrinos disappearing on the way?

25 min

Fields & matter

Neutrino Matter Resonance

When a neutrino passes through matter of changing density, does its quantum state keep up with the change?

25 min

Fields & matter

Supernova Neutrino Burst Observatory

When should a sudden jump in neutrino events trigger a supernova alarm?

25 min

Fields & matter

Liquid Argon Time Projection Chamber

How does a liquid argon detector use timing to get a track’s third dimension?

25 min

Fields & matter

Atmospheric Neutrino Zenith Experiment

How can the direction atmospheric neutrinos come from reveal that some change flavor?

25 min

Fields & matter

Neutrino Flavor Propagation

Why does the chance of finding a neutrino in each flavor rise and fall as it travels?

25 min

Fields & matter

Reactor Antineutrino Coincidence

Can you widen the timing window to catch more reactor antineutrinos without letting in too many false pairs?

20 min

Fields & matter

Cherenkov Light & Detector Rings

When does a cone of light become a ring?

20 min

Fields & matter

IceCube: From Sensor Hits to a Track

Can the light recorded by IceCube’s sensors reveal which way a particle was going?

20 min

Fields & matter

Electron–Matter Signal Map

When an electron beam enters a specimen, where do the different signals come from?

20 min

Fields & matter

Raster Scan & Drift Recovery

Can aligning repeated frames undo the distortion that drift causes in a scanned image?

20 min

Fields & matter

Electron Diffraction & Reciprocal Space

Which reciprocal-lattice points become detector spots?

20 min

Fields & matter

Spin ARPES: Polarization & Counting

When reversing a spin detector's magnetization changes the count, is that spin or unequal photon flux?

25 min

Fields & matter

SEM Microanalysis: EDS & WDS

Do X-ray counts at the vanadium energy prove that a sample contains vanadium?

25 min

Fields & matter

FIB Lamella: From Bulk to TEM Grid

How do you lift out a thin specimen without losing its support or useful material?

20 min

Fields & matter

Electron Lithography: Draw, Expose, Develop

Why do isolated and dense lines develop differently?

20 min

Fields & matter

CBED: Read Thickness Inside the Disc

Can a CBED disc tell a crystal's thickness apart from its tilt?

25 min

Fields & matter

MicroED: Rotate, Integrate, Fit the Basis

If the crystal turns through only a limited angle, along which directions can its diffraction locate the atoms?

25 min

Fields & matter

Aberration Corrector: Tune the Electron Probe

Can a wider cone of electrons focus to a sharper probe?

25 min

Fields & matter

Electron Ptychography: Recover Phase from Overlap

What do overlapping probe positions add to a set of diffraction patterns?

25 min

Fields & matter

Multi-beam SEM: Calibrate Before Stitching

Can a multi-beam SEM scan faster and still stitch its tiles into a seamless image?

25 min

Fields & matter

Ultrafast TEM: Resolve Time Without Losing Counts

Can many weak electron pulses capture fast dynamics that one intense pulse would blur?

25 min

Fields & matter

Single-particle Cryo-EM: From Movies to a Map

Can more particle images fill in a missing viewing direction?

30 min

Fields & matter

Photoelectron Structure: Direction and Depth

What can photoelectron diffraction and standing-wave scans tell you about where atoms sit?

30 min

Fields & matter

Electron Tomography: Reconstruct the Missing View

How much of a specimen's three-dimensional structure can a tilt series recover?

25 min

Fields & matter

Cryo Electron Tomography: Spend Dose, Average Copies

Can averaging many copies of a structure pull its signal out of the noise in a cryo-electron tomogram?

25 min

Fields & matter

Environmental SEM: Keep Water, Control Charge

Can chamber gas stop a wet insulator from drying out and charging without blurring the probe?

20 min

Fields & matter

Cryo-SEM: Preserve Before You Observe

Can you distinguish freezing damage, frost, charging and beam damage?

20 min

Fields & matter

STEM-in-SEM: Through a Thin Specimen

How thin must a specimen be for a useful SEM transmission image?

20 min

Fields & matter

STEM Detectors: Choose the Scattering Angle

Which electrons make columns of heavier atoms look brighter in a STEM image?

20 min

Fields & matter

EBSD: From Bands to Grains

Can you trust an EBSD grain map made with a bad calibration?

25 min

Fields & matter

TKD: Through the Nanocrystal

Can a thinner specimen resolve smaller grains?

25 min

Fields & matter

BSE: Composition or Orientation?

Can brighter grains prove a different composition?

20 min

Fields & matter

Low-energy SEM: Slow at the Surface

Can electrons travel fast in the column and land gently?

20 min

Fields & matter

Scanning Auger: A Few Nanometres

Can a sharp Auger elemental map hide beam damage to the surface chemistry?

25 min

Fields & matter

Inverse Photoemission: Empty States

What can emitted photons tell us about empty electron states?

25 min

Fields & matter

FIB-SEM: From Slices to Volume

When can clear slices produce a wrong volume?

25 min

Fields & matter

Block-face SEM: Between the Cuts

Can sharp block-face images still miss structures that lie between two cuts?

25 min

Fields & matter

In-situ TEM: Measure a Thermal Rate

In an in-situ heating experiment, is the electron beam only watching the transformation or also driving it?

25 min

Fields & matter

Liquid-cell TEM: Observing or Driving?

Does a clearer liquid-cell movie give a more reliable reaction rate?

25 min

Fields & matter

Lorentz TEM: Where the Walls Appear

Why does a magnetic domain wall switch from bright to dark when the defocus is reversed?

25 min

Fields & matter

Electron Holography: Recover the Hidden Phase

Can electron holography separate the magnetic part of the phase from the electric part?

25 min

Fields & matter

Dynamical Diffraction: When Intensity Returns

Does a thicker crystal always send more intensity into diffraction?

25 min

Fields & matter

Precession Diffraction: From Spots to Grains

Can swinging the electron beam around a cone make grain orientations easier to identify?

25 min

Fields & matter

Cathodoluminescence: Where Light Is Born

Does a dark spot mean the beam generated fewer carriers?

25 min

Fields & matter

Vibrational EELS: Resolution & Aloof Probes

How far can you narrow the electron source's energy band to sharpen a vibrational spectrum?

25 min

Fields & matter

STEM-EDS: Nanochemical Maps

Does a sharper electron probe guarantee a sharper chemical map?

25 min

Fields & matter

PEEM: Thresholds & Magnetic Domains

Can PEEM tell magnetic contrast apart from brightness caused by uneven illumination?

25 min

Fields & matter

LEEM: Surface Reflection & Diffraction

Can imaging with a single diffracted beam pick out one kind of surface domain?

25 min

Fields & matter

Micro / Nano ARPES: Spots & Domains

Can a smaller light spot resolve a narrow domain without damaging it?

25 min

Fields & matter

Momentum Microscopy: Time-of-Flight Cube

When does time-of-flight counting distort the band map in a momentum microscope?

25 min

Fields & matter

Time ARPES: Pulses & Relaxation

Does a decay measured in time-resolved ARPES show the true lifetime or the length of the pulses?

25 min

Fields & matter

APXPS: Gas, Reaction & Operando States

When an XPS peak weakens under gas, is that the gas or a change in the surface?

25 min

Fields & matter

HAXPES: Depth & Buried Interfaces

Can higher-energy X-rays reveal a layer buried under the surface?

25 min

Fields & matter

XPS: Elements, Chemical States & Charging

How can you tell whether a shifted XPS peak comes from a chemical change or from charging?

25 min

Fields & matter

UPS: Valence Bands & Work Function

Which two edges of a UPS spectrum give the work function?

25 min

Fields & matter

4D-STEM: One Scan, Many Virtual Images

What can you learn by recording a full diffraction pattern at every probe position?

25 min

Fields & matter

DPC: Beam Deflection & Projected Fields

When does the shift of the diffraction disk measure the field in the specimen?

25 min

Fields & matter

EELS: Energy Loss & Thin-Specimen Signals

What do electrons lose when they pass through a thin specimen?

20 min

Fields & matter

EFTEM: Energy Windows & Elemental Maps

Does a bright energy-filtered pixel mean more carbon?

25 min

Fields & matter

HRTEM Phase Contrast & CTF

Can the same atoms look dark in one high-resolution TEM image and bright in another?

20 min

Fields & matter

TEM Bright Field, Dark Field & SAED

In a TEM, which aperture selects one beam and which selects one region of the specimen?

20 min

Fields & matter

SEM Secondary-Electron Topography

Does a brighter surface mean a taller surface?

20 min

Fields & matter

TEM Mass–Thickness Contrast

Why does a denser inclusion look dark in bright-field TEM?

20 min

Fields & matter

Photoemission & Hemispherical Analyzer

Can you resolve two close peaks in a photoelectron spectrum without losing most of the counts?

20 min

Fields & matter

ARPES Band & Fermi-Surface Mapping

How does an emission angle reveal an electronic band?

20 min

Fields & matter

Electron Scattering & Mean Free Paths

How thin must a specimen be to avoid multiple scattering?

20 min

Fields & matter

Vacuum, Charging & Conductive Coatings

Can you stop charging without hiding the surface?

20 min

Fields & matter

Electron Dose, Noise & Damage

When does more exposure stop revealing more detail?

20 min

Fields & matter

Electron Wavelength & Voltage

Is higher accelerating voltage always better?

18 min

Fields & matter

Electron Gun Workbench

Which electron source gives the most coherent beam?

18 min

Fields & matter

Electron Optical Column

Can you focus an electron probe to a small spot and still keep enough current?

18 min

Fields & matter

Electron Resolution & Aberration Budget

Once spherical aberration is corrected, what limits how small the probe can be?

18 min

Fields & matter

How an Offset Circle Becomes a Lifting Airfoil

What sets how much circulation an airfoil carries, and so how much lift it makes?

12 min

Fields & matter

Make an Electric Field Visible

How can the shape of the electric potential tell you the force on a charge?

8 min

Fields & matter

Billions of Collisions in a Gas

How do random collisions settle into a steady pressure, temperature and speed distribution?

7 min

Fields & matter

A Charge Bending through Fields

How can a magnetic field turn motion without changing speed?

10 min

Fields & matter

Why a Spinning Ball Curves

How does tilting a ball's spin axis change the way it curves and where it lands?

8 min

Fields & matter

How One Moving Wall Drives an Entire Fluid

Why does a right-moving lid create one giant clockwise circulation inside a sealed cavity?

12 min

Fields & matter

How Neighbors Reconstruct a Splashing Pool

How can particles that only sense their neighbors work out the density and pressure of splashing water?

16 min

Fields & matter

How a Tiny Ripple Rolls into a Shear Vortex

When does a ripple between two fluid layers sliding past each other start to grow?

16 min

Fields & matter

Bend a Wall, Transform a Flow

Why does a conformal map change flow speeds near corners even though it preserves angles?

12 min

Fields & matter

Stretch the Dye, Keep the Rotation Ledger

How can a flow with no viscosity stir dye into fine threads without losing energy or rotation?

14 min

Fields & matter

Let Pressure Write the Shock Diamonds

Why does a supersonic jet form a chain of diamonds when its exit pressure differs from the surrounding air?

16 min

Fields & matter

Push a Numerical Jet by Hand

What do advection, diffusion and pressure projection each do in a fluid simulation?

12 min

Fields & matter

How Phase Turns Flapping into Propulsion

How does the timing between a wing's heaving and pitching decide whether it makes drag or thrust?

14 min

Fields & matter

Why a Symmetric Wake Breaks Itself

Why does the wake behind a fixed cylinder shed vortices from alternate sides?

12 min

Fields & matter

How Signed Singularities Assemble Fluid Orbits

How do a handful of point vortices move one another?

14 min

Fields & matter

How One Diaphragm Creates Three Compressible Waves

Why does bursting the diaphragm in a shock tube send out a shock, a contact surface and a rarefaction fan?

15 min

Fields & matter

How a Thermal Gradient Organizes into Rolls

When does a fluid layer heated from below start to convect?

12 min

Fields & matter

Immune Design from Molecule to Organoid

How does a T cell recognizing an antigen lead to clearing targets across a whole tissue?

12 min

Fields & matter

From Hard Spheres to Boltzmann

How can the Boltzmann equation be derived rigorously from Newtonian collisions of hard spheres?

14 min

Fields & matter

Why Two Vortex Rings Leapfrog

Why does the rear vortex ring shrink and slip through the front one?

12 min

Fields & matter

How Rotating Shear Fractures into Taylor Cells

Why can fluid swirling between two cylinders break up into stacked rolls?

14 min

Fields & matter

WBE and the Quarter-Power Pace of Life

How can a branching supply network explain why metabolism and heart rate scale with body mass?

12 min

Fields & matter

How Stars Build Elements up to Iron

Why does fusion release energy only until nuclei approach iron?

15 min