Atmospheric Pressure

Did you know that air has weight? This illustrated essay from the NOVA Web site explores conditions that affect air density and atmospheric pressure.

Atom Builder

Build a carbon atom out of up quarks, down quarks, and electrons in this interactive activity from the NOVA Web site.

Atomic Structure of an Alloy

Learn about the atomic structure of bronze, a copper alloy, in this video excerpt from NOVA: "Hunting the Elements."

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Bend, Twist and Break: Beyond the Laboratory

Dr. Chris Muhlstein explains that when scientists study fracture surfaces from controlled experiments to understand the resulting shapes and features, they can use their understanding to deduce what happened when they were not around to see the material fail or break. Further they can predict what will have to a larger or smaller piece of material under stress. This process is how scientists and engineers translate a lab experiment into a design for an airplane, bridge or even a bike frame.

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Bend, Twist and Break: Breaking Glass

Dr. Chris Muhlstein explains that researchers learn about the scientific basis for failure of materials by running experiments in the lab, using a simple shape like a glass rod to calculate the strength of material and predict its failure. The same tests can be done at the micro and nano scale using tiny specimens. Students can run a similar experiment with a bar of chocolate.

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Bend, Twist and Break: Fracture Surfaces

Dr. Chris Muhlstein explains that fracture surfaces can reveal how and why a material has failed. An image of a fracture surface has features or shapes that we can use to understand where a material failed and why. Scientists use an optical microscope or a scanning electron microscope to read a fracture surface at high magnifications, much like we read maps to find our way.

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Bend, Twist and Break: The Bridge

Dr. Chris Muhlstein explains that the arrangement of atoms in a material determines the properties. He drops an iPod to illustrate how the arrangement of atoms can protect it from damage; he narrates footage of the collapse of the Tacoma Narrows Bridge in the 1940s to show how the deformation of materials can cause the collapse of a structure.

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Birth of a Supernova, Type Ia

In this interactive activity from NOVA Online, learn about a type of exploding star — a Type Ia supernova — that is so bright that astronomers can measure the distance to the galaxy in which it resides, and even learn which elements make up the star.

Birth of a Supernova, Type II

In this interactive activity from NOVA Online, learn about a type of exploding star — a Type II supernova — that is so large it has a mass 10 times greater than the mass of our Sun.

Breaking Things on Purpose

*Materials such as metals (aluminum, iron, copper, etc.), ceramics (silicon carbide, porcelain) or polymers (milk jugs made of polyethylene) are tested by scientists and engineers to reveal certain mechanical properties such as the maximum stress a material can withstand. The stress at which a material breaks is a measure of its strength. In this lesson you will be testing the strength of a delicious material you know as chocolate!

Build a Steroid

In this interactive activity from NOVA, learn about the molecular structure of steroids. See the intermediate molecules that are part of the pathway for synthesizing cortisone from diosgenin.

Building Blocks of Matter

Structure of matter.

Carbon Cycle Diagram

This diagram from NASA's Earth Science Enterprise illustrates Earth's carbon cycle.

Chernobyl: What Really Happened?

This text excerpted from Richard Rhodes' book, Nuclear Renewal and reprinted on the FRONTLINE Web site examines the causes of the Chernobyl accident.

The Dating Game: Radioactive Carbon

In this media-rich essay from the NOVA Web site, learn about the atomic structure of radioactive carbon and how it can be used to determine the age of organic remains, such as bones and teeth.

Design an Ion Engine

Learn about ions and then design an ion engine to maximize thrust in this interactive activity adapted from NASA.

Diamonds: The Science Behind the Sparkle

This illustrated essay from the NOVA Web site explains why the atomic structure of a diamond slows down light and produces a sparkle more brilliant than from any other colorless substance.

Disappearing Milk

A magician pours milk into a glass, but when he turns the glass upside down, nothing comes out. How does he do it? Discover the science behind the "magic" in this video adapted from the American Society of Mechanical Engineers.

Discovering Air

Our understanding about the air we breathe has changed dramatically through time. This illustrated timeline from the NOVA Web site tracks the changing thought on air and the creation of the Periodic Table of the Elements.

Dissolving Salts in Water

In this interactive activity adapted from Iowa State University, design and carry out an experiment: dissolve salts in water, see how different ionic compounds produce different reactions, and observe the resulting changes in temperature.

Electric Charges Interact

Experiment with electric charges to find out how they interact in this interactive activity adapted from NASA.

Elements of Steel

This resource from the AMERICAN EXPERIENCE Web site, which contains both an interactive activity and illustrated text, looks at the composition of different types of steel and their impact on technology.

Everyday Radiation

How much radiation are we exposed to every day? Find out in this video segment adapted from FRONTLINE.

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Facts About Radiation

This document from the FRONTLINE Web site offers examples of everyday exposure to radiation.

FAQs About Nuclear Power

Nuclear physicist, Dr. Charles Till, answers questions about nuclear power in this interview from the FRONTLINE Web site.

Fission and Reprocessing: How They Work

This video-enhanced document from the FRONTLINE Web site explains how nuclear fission and nuclear reprocessing work.

Floating and Sinking: Hot Air Balloons

Why do hot air balloons float? This resource from the NOVA Web site offers a series of interactive activities that illustrates the physics of hot air balloons.

Fluid Dynamics

In this video from NASA Launchpad, learn about the techniques and facilities astronauts use to train for working in microgravity environments.

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Fusion: Testing the First Hydrogen Device

This video segment adapted from AMERICAN EXPERIENCE features original footage of the U.S. test of the first hydrogen device, code-named "Mike", that would trigger thermonuclear fusion.

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Fusion: The Hydrogen Bomb

Just after World War II, nuclear scientists turned their attention from fission to fusion. This video segment adapted from AMERICAN EXPERIENCE looks at the beginnings of thermonuclear power generation.

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Get Close to a Nuclear Fission Reaction!

Learn how scientists regulate a nuclear reactor in this animation-enhanced essay from the FRONTLINE Web site.

Global Warming and The Greenhouse Effect

This video excerpt from Race to Save the Planet discusses the greenhouse effect and global warming.

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Global Warming: Beyond Fossil Fuels

Martin Hoffert, professor of physics at New York University, discusses global warming and alternative energies in this interview from the NOVA/FRONTLINE Web site.

Global Warming: Graphs Tell the Story

Examine these graphs from the NOVA/ FRONTLINE Web site to see dramatic increases in the temperature of Earth's surface and greenhouse gases in the atmosphere.

History of the Universe

This interactive timeline from the NOVA Web site recaps the theoretical origin and formation of the universe, and forecasts its eventual fate.

How Hard is Chocolate?

Hardness is probably a concept you are well familiar with. You already know that certain materials are harder than others; in fact, you prove it everyday when you chew your food and your teeth don’t break (because your teeth are harder than the foods you chew). Hardness can be defined as a material's ability to resist a change in shape. Modern hardness testers take a well-defined shape and press it into a material with a certain force, observing the indent it leaves in the material when it is removed. In this lesson, you will be performing hardness testing on different bars of chocolate.

The Impact of Technology: Nylon

This video segment adapted from A Science Odyssey looks at the invention of nylon.

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Ionic Bonding

In this interactive activity from ChemThink, learn how ionic bonds are formed and how an ionic bond structure is represented by its formula.

Island of Stability

In this video segment adapted from NOVA scienceNOW, follow scientists in their quest to understand how stable elements are made and how to create the elusive element 114.

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Making Cortisone From Plants

This video segment adapted from NOVA is a dramatized story of chemist Percy Julian’s work to synthesize cortisone. Find out how a biological process, not a chemical one, proved the key to producing cortisone in bulk.

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Measuring Bond Energy of an Ionic Compound

In this media-rich lesson, students investigate bond energy and the law of conservation of energy. They examine the chemistry behind instant cold packs by using a calorimeter to study the endothermic dissociation of ammonium chloride in water.

Mechanical Properties of Chocolate: How Hard is your Chocolate?

Hardness is probably a concept you are well familiar with. You already know that certain materials are harder than others; in fact, you prove it everyday when you chew your food and your teeth don’t break (because your teeth are harder than the foods you chew). Hardness can be defined as a material's ability to resist a change in shape. Modern hardness testers take a well-defined shape and press it into a material with a certain force, observing the indent it leaves in the material when it is removed. In this lesson, you will be performing hardness testing on different bars of chocolate.

Mechanical Properties of Chocolate: How Strong is your Chocolate?

*Materials such as metals (aluminum, iron, copper, etc.), ceramics (silicon carbide, porcelain) or polymers (milk jugs made of polyethylene) are tested by scientists and engineers to reveal certain mechanical properties such as the maximum stress a material can withstand. The stress at which a material breaks is a measure of its strength. In this lesson you will be testing the strength of a delicious material you know as chocolate!

Melissa Franklin: High Energy Physics

This video segment adapted from Discovering Women profiles Fermilab physicist and Harvard professor Melissa Franklin.

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Nanotechnology

Learn about the fundamentals of nanotechnology and its applications, in this video segment adapted from Pennsylvania College of Technology and WVIA.

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A Nanotube Space Elevator

In this video adapted from NOVA scienceNOW, find out about the discovery of a new building material, the carbon nanotube, whose physical properties could theoretically enable the creation of a 22,000-mile elevator to space.

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Nature's Pharmacy

In this interactive activity from NOVA, learn about chemicals in nature that are used in medicine.

NOVA Elements

Explore the periodic table, and build atoms and molecules in this web edition of the NOVA Elements iPad App.

Nuclear Blast Damage

This illustrated document from the AMERICAN EXPERIENCE Web site examines the "zones of destruction" caused by nuclear weapons.

Nuclear Blast Footage

These video clips from the AMERICAN EXPERIENCE Web site feature actual footage of thermonuclear blast testing done in the 1950s.