Video / Animation
Absorption of Light
This animation explains how a material's chemical composition affects the wavelengths of light it absorbs and the color it displays.
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Video / Animation
Alpha, Beta, and Gamma Rays
This animation explains the difference between the alpha particles, beta particles, and gamma rays emitted by various radioactive materials.
Video / Animation
Are Invisibility Cloaks Possible?
Have you ever wished you could hide under an invisibility cloak, like Harry Potter did? This video explores the science behind light, sight, and invisibility. Though we can’t make ourselves invisible yet, some promising research may light the…
Video / Animation
Are We Running Out of Helium?
Helium has helped create revolutionary scientific innovations, and has industrial uses that simply cannot be replicated. Yet helium—a gas that defies gravity—is constantly being lost as it escapes Earth’s atmosphere into space. This video…
Video / Animation
Chain Reaction
This animation shows how a nuclear chain reaction works and explains how it is used in nuclear fission devices.
Video / Animation
Chaotic System
This animation shows how chaotic systems are unpredictable because of their extreme sensitivity to their initial conditions.
Video / Animation
The Chemistry of Aerosol Shaving Cream
People who shave share one concern—the threat of razor-sharp metal. Luckily, aerosol-based shaving cream packs the right chemistry to protect sensitive skin, thanks in part to surfactants. Watch this video to learn more about this fantastic…
Video / Animation
The Chemistry of Snowflakes
This video tracks the formation of snowflakes from their origins in bits of dust in clouds that become droplets of water falling to Earth. As each snowflake rises and falls through warmer and cooler air, it develops its own distinctive shape.…
Video / Animation
Collision (physics)
This animation explains the phenomenon of collision and shows the difference between elastic and inelastic collisions.
Video / Animation
Conservation of Energy
This animation explains conservation of energy and shows how the total amount of kinetic and potential energy in an isolated system is constant.
Video / Animation
Conservation of Momentum
This animation explains the phenomenon of conservation of momentum and shows how momentum is the product of mass and velocity and is conserved in collisions.
Video / Animation
Damping and Shock Absorption
This animation describes how a shock absorber minimizes the effect of shock on a mechanical system.
Video / Animation
Do Astronauts Need Sunscreen?
How do astronauts survive the deadly radiation of deep space? NASA is still figuring out how to protect astronauts from cosmic radiation using plastic shielding and magnetic deflectors. Credit: Reactions/American Chemical Society
Video / Animation
Doppler Shift
This animation explains the Doppler shift and shows how the movement of a sound source relative to a listener raises or lowers the pitch.
Video / Animation
Echo
This animation explains echoes and shows how echoes occur when soundwaves bounce off objects.
Video / Animation
Five Surprising Facts About Crystals
From the dinner table to the human body, crystals are everywhere. This video highlights five scientific facts about this ubiquitous solid. [Credit: Reactions/American Chemical Society (www.youtube.com/acsreactions)]
Video / Animation
Food Myths #1: No, Your Microwave Isn't Dangerous
We all want to be healthy, but some food myths can actually get in the way of good nutritional decisions. This video shatters one food myth that you may have heard: microwaving your food zaps its nutritional value. Watch to find out why that…
Video / Animation
Fried Chicken’s Deliciousness, Explained
Battered and deep-fried chicken might be one of the world's most delicious foods. But what makes fried chicken so tasty? It all comes down to the chemistry of frying. In the video, learn how the delicate dance of fat at high temperatures…
Video / Animation
Graphene: The Next Wonder Material?
This video explains how graphene's remarkable properties come from the unique arrangement of its atoms. (Correction: The video's narration incorrectly states that Andre Geim and Konstantin Novoselov are chemists. Both Geim and Novoselov are…
Video / Animation
Gravity
This animation shows how all objects fall at the same rate of accelleration due to the force of gravity.
Video / Animation
Harmonic Motion-Damping
This animation explains harmonic motion damping and shows how an applied force can decrease a simple harmonic motion.
Video / Animation
Have We Found All the Elements?
Four elements were added to the periodic table in 2016, completing the seventh row. However, these new elements are not naturally occurring. Scientists had to create them and overcome a number of challenges to do so. This video explains some…
Video / Animation
How Air Conditioning Works
To beat the heat, many people turn to air conditioning. That sweet, cool relief isn’t magic, it’s the science of heat transfer and the chemistry of refrigerants. This video explains the science and chemistry of air conditioning. Credit:…
Video / Animation
How Can You See an Atom?
Since ancient Greek times, philosophers and scientists have tried to figure out what an atom looks like. It wasn't until the 1980s that chemists could see individual atoms. In this video, bestselling author Sam Kean discusses the nearly…
Video / Animation
How Do Airbags Work?
If you’re in an automobile accident, you want to be sure the vehicle's airbags protect you. Airbags work because of chemistry, with some physics thrown in. This video explores the science of airbags. And remember, airbags are meant to work in…
Video / Animation
How Do Snowflakes Form?
A large snowstorm could produce trillions of tiny snowflakes. Through advances in crystallography, scientists have learned much about the structure of this form of precipitation. Although snowflakes all start out similarly, once they begin…
Video / Animation
How Do Some Animals Glow?
What's the difference between fluorescence and bioluminescence? This video illuminates the biochemical distinctions. Credit: Reactions/American Chemical Society
Video / Animation
How Fluorescence Works
Have you ever wondered what makes a fluorescent color stand out so brightly from other colors? This video digs into what makes those colors pop, and highlights some of the brilliant applications of fluorescence coming out of nanotechnology.…
Video / Animation
How Much Does a Cloud Weigh?
This video explores the chemistry behind how clouds develop and how they stay aloft in the sky, despite their tremendous weight. Credit: Reactions/American Chemical Society
Video / Animation
How to Fry a Turkey
When Thanksgiving comes around, many people think about taking their turkey preparation to the next level. But before you whip out that deep fryer, you're going to want to watch this video. This video brings you the do's and don'ts of turkey…
Video / Animation
How to Keep Your Phone Battery Charged Longer
New smartphones are slimmer and faster than ever. But like most new generations of smartphones, their battery has pretty much stayed the same over the years. Short of carrying an external battery all the time, is there any way to extend the…
Video / Animation
How to Make Fluorescent Flowers
Do you have a special someone you want to impress? This video might help. Learn how to turn white flowers into fluorescent masterpieces. Credit: Reactions/American Chemical Society
Video / Animation
Innovative Ways to Fight Climate Change
This video examines some novel proposals for combating climate change—including space mirrors, seeding the ocean with iron, and feeding cows seaweed. In reality, these ideas may or may not be feasible, but they are all supported by valid…
Video / Animation
Laminar Flow
This animation explains the phenomenon of laminar flow and shows how the movement of air past a moving vehicle creates laminar flow and boundary flow.
Video / Animation
Laser
This animation shows how lasers result from the light amplification by stimulated emission of radiation and explains why laser beams are sharply focused.
Video / Animation
The Leidenfrost Effect
Have you ever seen a drop of water navigate a maze? It’s possible, thanks to an unusual phenomenon called the Leidenfrost Effect. Understanding this effect—first described more than 200 years ago—helped engineers make more efficient steam…
Video / Animation
Lever
This animation explains the concept of a lever and shows how the amount of force a lever exerts depends on the distance between the fulcrum and the end of a lever.
Video / Animation
Pulley
This animation shows how a pulley applies the concept of mechanical advantage to make it easier to lift heavy objects.
Video / Animation
Quantum Mechanics
This animation shows how the behavior of quantum mechanical systems differs from that of classical systems and allows phenomena that would be impossible in classical mechanics.
Video / Animation
Reflection and Refraction
This animation shows how light moving into a denser medium is both reflected and refracted.
Video / Animation
Reverberation
This animation explains how the reverberation of sound results from the echo bouncing off the walls of a room.
Video / Animation
The Science Behind the Chernobyl Accident of 1986
This video explores the chemistry and physics behind the disastrous explosion of the former Soviet Union’s Chernobyl Power Complex nuclear reactor 4 on April 26, 1986. The Chernobyl disaster was the only accident in the history of commercial…
Video / Animation
Sound Waves
This animation shows how the sound of a complex tone depends on the sum of the waveforms of the simple tones contributing to it.
Video / Animation
Stereophonic Sound
This animation explains how stereophonic sound results from recording and playing back multiple microphone tracks simultaneously.
Video / Animation
The Universe in a Cup of Coffee
This video does a deep dive on the surprisingly complex chemistry behind many people's favorite morning beverage: coffee. The chemistry of the universe is, in a way, in your morning cup of coffee—from the evolution of caffeine as a defensive…
Video / Animation
Vertical Farming
There’s a new trend in agriculture called vertical farming. When humans first learned to farm, we arranged plants outside in horizontal fields, and then invented irrigation and fertilizers to grow crops. But with modern technology and…
Video / Animation
What Are Isotopes?
This video explores the basics of isotopes, including what they are and why they are important. Credit: Reactions/American Chemical Society
Video / Animation
What Causes Auroras?
There are many misconceptions about what causes auroras as well as when, where, and how they occur. Watch this video to learn the true answers. Credit: Reactions/American Chemical Society
Video / Animation
What Do Thermometers Measure?
We place a lot of trust in modern thermometers, but do you know how those instruments actually work? The answer involves thermodynamic principles. Physical chemists and engineers have taken temperature-measuring tools from the simple—but…
Video / Animation
What is the Blackest Black?
Go to any paint store, and you’ll see a dozen or so variations of the color black. But what is the darkest one available? This video looks for—and finds—the blackest black material. Credit: Reactions/American Chemical Society
Video / Animation
What's That After-Rain Smell Made Of?
There’s a sweet smell in the air after it rains, whether it’s been a spring shower or a summer storm. This video explains the chemistry of petrichor, the smell of rain. Credit: Reactions/American Chemical Society
Video / Animation
Women in Chemistry: Heroes of the Periodic Table
This video shares the story of two of chemistry’s most brilliant and bold women and their paths of elemental discovery. What these women brought to the table changed the world as we know it. Credit: Reactions/American Chemical Society
Video / Animation
Work
This animation explains how physical work is the product of force times the distance over which it is applied.
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from article Nuclear isomerism
Decays of isomers in (a) 77Kr and (b) 77Zn, showing the effects of energy and change of spin/parity on the lifetimes of the states. Numbers and “+” or “−” signs to the left of levels give their spins and parities, and numbers to the right of levels…
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from article Nuclear isomerism
Decays of shape isomers in (a) 74Kr and (b) 238U. Labeling of levels and gamma transitions is the same as in Fig. 1.
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from article Nuclear isomerism
Decay of the spin-gap 95mPd isomer. Labeling of levels and of the gamma transition from the isomeric (21/2+) level is the same as in Fig. 1.
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from article Boiling
Typical boiling curve, showing qualitatively the dependence of the wall heat flux q on the wall superheat ΔT, defined as the difference between the wall temperature and the saturation temperature of the liquid. Schematic drawings show the boiling…
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from article Boiling
Effect of external forced flow, at low and high velocity, on the boiling heat curve. The maximum heat flux is increased and the natural convection curve is shifted up due to forced convection. Locations of points A and C in Fig. 1 are indicated.
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from article Spin-density wave
Types of spin-density wave observed in metals: SS = spiral (helical); FS = ferromagnetic (cone); = skewed; LSW = longitudinal; TSW = transverse; FAN = stable only in a magnetic field B in the direction shown.
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from article Pitot tube
Pitot tubes. (a) Original form. Symbols explained in text. (b) Modern shielded Kiel probe.
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from article Thermistor
Bridge circuit for measuring radio-frequency power by use of a pair of thermistors.
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from article Aerodynamic sound
Separate-flow high-bypass-ratio jet engine.
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from article Aerodynamic sound
Sources of airframe noise.
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from article Mechanical vibration
Vibrating linear system (mass-spring-damper) with one degree of freedom.
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from article Mechanical vibration
Variation of amplitude of vibration with forcing frequency and damping. Xmax = maximum displacement.
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from article Mechanical vibration
Impedance of a simple oscillator.
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from article Mechanical vibration
Comparison of suggested building damage criteria and human threshold of perception curves for whole-body vibration. Acceleration level in dB = 20 log acceleration level/g. Because they are negative logarithms, the decibel values on the vertical axis…
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from article Mechanical vibration
Levels of perceptibility of vibration and audibility of noise. Acceleration level in dB = 20 log acceleration level/g. Because they are negative logarithms, the decibel values on the vertical axis indicate increasing acceleration levels from bottom…
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from article Electron spectroscopy
Excitation of electron spectra recorded with high-resolution instruments. (After H. Siegbahn and L. Karlsson, Photoelectron spectroscopy, Handbuch der Physik, vol. 31, 1982)
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from article Electron spectroscopy
The system of levels of an atom in a molecule can be divided into a valence electron region and an atomic-core region. Excitation of electron lines from the various regions can be made at different photon energies.
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from article Electron spectroscopy
Valence-band electron spectrum of gold excited by monochromatized Al Kα radiation (solid curve). Comparison is made with a theoretically calculated density of states (broken curve) which has been folded with a 0.25-eV gaussian corresponding to the…
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from article Electron spectroscopy
Benzene valence electron spectrum excited by Hel radiation at 21.22 eV, showing vibrational structures.
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from article Electron spectroscopy
ESCA spectrum of cesium fluoride (CsF) in glycol (HOCH2CH2OH) solution. Comparison is made with the corresponding electron-binding energies in the gas phase. (After H. Siegbahn et al., Phys. Scripta, 27:431, 1983)
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from article Electron spectroscopy
Electron spectrum from the 1s level of carbon in ethyl trifluoroacetate; binding energy = 291.2 eV.
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from article Electron spectroscopy
Binding-energy shifts for the sulfur 2p electrons versus the calculated charge. The points indicate averages from more than 100 compounds.
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from article Matthiessen's rule
Resistivity of copper and copper alloys. Solute concentrations are given in atomic percent. °F = (°C × 1.8) + 32. (After J. O. Linde)
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from article Colloidal crystals
Arrangement of particles and distribution of electrical charges in a charged stabilized body-centered-cubic colloidal crystal. Spheres indicated by broken lines show extent of positive counterion clouds.
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from article Colloidal crystals
Reflection of white light from a polycrystalline colloidal crystal suspension. The crystals are body-centered cubic, with a particle diameter of 0.1 μm and interparticle spacing of 1.5 μm.
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from article Colloidal crystals
Inverse opal structure formed by filling the void space of a face-centered cubic colloidal crystal emulsion of oil drops in water and then condensing silica in the aqueous void spaces. (D.J. Pine, University of California at Santa Barbara)
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from article Analog states
Partial level diagram of the 208Pb and 208Bi isobar system. Broken lines connect parent–analog state pairs. Energies of excited states are given relative to the ground states, respectively, in megaelectronvolts. The isospin, T, and the angular…
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from article Steam
Vapor-tension curve for water. 1 lb/in.2 abs. = 6.895 kPa, absolute pressure. °C = (°F − 32)/1.8.
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from article Steam
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from article Steam
Temperature-enthalpy chart for steam. 1 Btu/lb = 2326 J/kg. °C = (°F − 32)/1.8.
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from article Steam
Temperature-entropy chart for steam. °C = (°F − 32)/1.8; 1 Btu/lb °F = 4186.8 J/ kg °C; 1 Btu/lb = 2326 J/kg; 1 ft3/lb = 62.4 × 10−3 m3/kg; 1 lb/in.2 = 6.895 kPa. (After J. H. Keenan and F. G. Keyes, Thermodynamic Properties of Steam, John Wiley and…
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from article Steam
Mollier diagram for steam. 1 Btu/lb = 2326 J/kg; 1 Btu/lb °F = 4186.8 J/kg °C; °C = (°F − 32)/1.8; 1 lb/in.2 = 6.895 kPa. (After Mollier's Steam Tables and Diagrams, Pitman, 1927)
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from article Watt balance
Diagram of the Watt balance, illustrating the working principle of the apparatus. Symbols are defined in text.
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from article Time
Division of the world into 24 time zones, progressively differing from Greenwich by 1 hour. Some countries use half-hour intervals or fractional hours. Letter designations are shown, and the key indicates number of hours by which zone time must be…
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from article Time
The improvement in timekeeping accuracy with time. The broken colored line shows the accuracy of clock measurements. The broken gray line shows the accuracy of the Earth's rotation in providing an accurate time scale.
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from article Quantum electrodynamics
Diagrams of photon absorption and emission. (a) Absorption of a photon (represented by a wavy line) by an electron (represented by a solid line with an upward arrow). (b) Emission of a photon by a positron (represented by a solid line with a…
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from article Quantum electrodynamics
Diagrams representing scattering of a photon on an electron caused by an exchange of a virtual electron. The electron and photon interact at space-time points x and y.
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from article Quantum electrodynamics
Diagrams representing encounters of an electron and a positron. (a) Scattering of a positron and an electron caused by an exchange of a virtual photon. (b) Mutual annihilation of an incident positron and electron into two photons.
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from article Quantum electrodynamics
Example of a diagram of order e04, involving two virtual photons and two virtual electrons. The diagram has a closed path of internal lines connecting the vertices x, z, and w.
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from article Quantum electrodynamics
Examples of divergent diagrams. (a) Electron self-energy diagram. (b) Photon self-energy diagram. (c) Vertex correction diagram.
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from article Binoculars
Modern prism binocular. (Bausch and Lomb Optical Co.)
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from article Harmonic motion
Representation of simple harmonic motion.
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from article Harmonic motion
Weight on an elastic spring. (a) Unloaded. (b) Statically loaded. (c) Weight and spring oscillating.
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from article Harmonic motion
Torsional pendulum.
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from article Harmonic motion
Three normal modes of the CO2 molecule. (a) Lower-frequency in-line mode. (b) Higher-frequency in-line mode. (c) Bending mode.
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from article Proton
An artist's impression of the three-quark composition of the proton, with up quarks colored red and the down quark colored blue. (Credit: Jefferson Lab)
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from article Proton
A diagram of an atom depicting red-colored, positively charged protons in the nucleus alongside green, neutrally charged neutrons. Yellow-colored, negatively charged electrons orbit the nucleus. In neutral atoms, such as this one, the number of…
