1900 Air Pollution

Examine this graph from FRONTLINE/NOVA: "What's Up with the Weather?" Web site to see dramatic increases in three greenhouse gases over the last two hundred years.

The Advantage of Sex

Why did sex evolve? The likely answers, in this essay for the Evolution Web site by science journalist Matt Ridley, may surprise you.

Amazing Heart Facts

This feature from the NOVA "Cut to the Heart" Web site highlights facts about the heart -- including its size and placement -- and will help you to understand the importance of this wondrous organ in our bodies.

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Animal Body Plans: Homeobox Genes

The homeobox genes that define the basic body plan of mice and fruit flies are illustrated in this graphic from The Human Evolution Coloring Book by Adrienne Zihlman. The accompanying article describes how these genes act as "molecular architects" in all animal species.

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Astronauts in Hard Hats

This media-rich series of interviews from the NOVA Web site explores the unique challenges faced by astronauts doing construction work in outer space.

Atmospheric Carbon Dioxide Levels

Earth is warming because of an increase in greenhouse gases, including carbon dioxide (CO₂). Explore what can be done to slow or stop continued climate change.

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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.

The Beginnings of the Telescope

This animated essay from the NOVA Web site examines the design of Galileo's refracting telescope and Sir Isaac Newton's reflecting telescope.

Buoyancy Basics

This illustrated demonstration from the NOVA Web site explains the concepts of buoyancy and density by showing what happens when different kinds of wood blocks are dropped in water.

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.

Chris Schneider: Rethinking Conservation

In this interview filmed for Evolution: "Darwin's Dangerous Idea," biologist Chris Schneider discusses the relationship between conservation and speciation.

CO₂ Concentrations at Mauna Loa Observatory, Hawaiʻi

This resource, adapted from the Carbon Dioxide Information Analysis Center, provides a graph of monthly average carbon dioxide (CO₂) concentration from 1958 to 2000 at the Mauna Loa Observatory in Hawaiʻi.

Complex Relations

In this text excerpted from chapter 3, "Struggle for Existence," of Charles Darwin's On the Origin of Species, Darwin draws on firsthand and historical information for his observations about evolution.

Convergence: Marsupials and Placentals

This graphic illustrates some of the marsupial mammals in Australia and placental mammals in North America. Even though they are not closely related, these mammals look alike because they have adapted to similar ecological roles. From The Human Evolution Coloring Book by by Adrienne Zihlman.

Dab of DNA Helps Keep Counterfeiters at Bay

Find out in this USA Today article how DNA sequences can vouch for a souvenir's authenticity.

Darwin's Letters: Collecting Evidence

This group of letters is a sample of the extensive correspondence Darwin carried on with a wide group of friends and colleagues as he collected evidence to support his theory of evolution by natural selection. From Charles Darwin's Letters: A Selection 1825-1859.

Darwin's Letters to Lyell

In this letter written to his friend and mentor Charles Lyell less than three weeks after the publication of On the Origin of Species, Darwin describes the reaction of the great anatomist Richard Owen to his theory. From Charles Darwin's Letters: A Selection 1825-1859.

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.

Decreasing California Snowpack

Approximately 40 percent of California's surface water supply originates from the snowpack in the Sierra Nevada Mountains. However, climate change is significantly altering this precious water source.

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Demolition Woman

Find out how controlled explosions are used to demolish multi-story buildings in this interview from the NOVA Web site.

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.

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.

DNA Fingerprint Photos

These photographs supplied by Genelex Corporation depict actual DNA fingerprints and show the types of information that can be gleaned from them.

DNA Makes History

Read how DNA was used to solve the mystery of the Romanov family's execution. From Human Genetics: Concepts and Applications by Ricki Lewis.

DNA on the Witness Stand

In this article, Dr. Eric Lander of the Human Genome Project comments on the use of DNA as an identification tool -- the theoretical versus the practical results.

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Dr. Jay Giedd: The Adolescent Brain

In this transcript from FRONTLINE: "Inside the Teenage Brain," neuroscientist Dr. Jay Giedd discusses new research on brain development in teenagers.

Einstein: A Timeline of His Life

This illustrated timeline from the NOVA Web site follows Albert Einstein's life, including 1905, his "Miracle Year," during which he developed his Special Theory of Relativity and the equation, E=mc².

Einstein: How Smart Was He?

This essay from the NOVA Web site explores the impact Einstein made on physics and most everything we know about the cosmos.

Evidence for Evolution

In this Evolution WebQuest you will investigate a variety of types of evidence for evolution.

Evolution on Double Time

This excerpt from Evolution: The Triumph of an Idea by Carl Zimmer describes how gene duplication may have been the key to the rapid evolution of the early stages of life on Earth.

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.

Farallon Islands Map

With this map from QUEST produced by KQED, explore what it is like to live on the rocky remote Farallon Islands for both birds and the scientists who explore them.

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Finch Beak Data Sheet

This graphic from Ecology and Evolution of Darwin's Finches by Peter Grant presents data from the Galapagos Islands, showing that a severe drought put selective pressure on the population of Darwin's finches and resulted in a change in the average beak size in the next generation.

Fission and Reprocessing: How They Work

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

Forecasting Suitable Habitat for North American Wolverines From the Present to 2100

Learn what plants and animals must do in order to survive significant environmental changes.

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Forensics

Find out how DNA profilers analyze bits of tissue to identify human remains. From NOVA: "Lost on Everest" Web site.

Galileo: His Place in Science

Einstein called Galileo the "father of modern physics." This media-rich essay from the NOVA Web site looks at Galileo's quest to understand the mathematics of motion.

Galileo: Timeline of His Life

This illustrated timeline from the NOVA Web site turns back the clock to the late 1500's to relive the dramatic life of one of the world's most renowned scientists.

Genetic Art

Take a peek at the artistic side of science in this virtual exhibit, featuring work by Eva Sutton, Alexis Rockman and Sidney Harris.

Genetics Case Studies

Wrestle with ethical issues concerning genetic rights and practices from the NOVA: "Cracking the Code of Life" Web site.

Genome Facts

This list from NOVA: "Cracking the Code of Life" Web site provides some of the basic, yet impressive, facts and figures about the Human Genome Project.

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: 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 graphs from the NOVA/FRONTLINE Web site to see dramatic changes in the temperature of Earth's surface and in the levels of greenhouse gases in the atmosphere.

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.

Global Weather Machine

In this illustrated essay from NOVA Online, explore the cyclical process of weather creation and the effects of El Niño on the global weather system.

The Greenhouse Effect and Greenhouse Gases

Increasing greenhouse gases are contributing to global warming, which is changing our climate.

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How Big Is the Universe?

In this media-rich essay from the NOVA Web site, astronomer Brent Tully of the University of Hawaiʻi walks you through the latest scientific theories about the size of the universe.

How DNA Evidence Works

In this article by An Meeker-O'Connell, discover how DNA evidence is processed before it goes to court.

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How Genetic Disorders Are Inherited

Learn how genetic disorders are passed from parents to children as explained in this excerpt from Blazing a Genetic Trail, from the Howard Hughes Medical Institute.

How to Conquer a Genetic Disease

In Blazing a Genetic Trail, by the Howard Hughes Medical Institute, follow this three-step approach to treating genetic diseases.

Hurricane Katrina: Possible Causes

This media-rich essay from NOVA scienceNow explores new research into hurricanes that may help explain Katrina's devastating impact and discusses the possibility that global warming played a role.

Is Lactic Acid a Four Letter Word?

This essay by Patti and Warren Finke describes the process by which our bodies transform food energy into energy that our cells can use.

The Leaning Tower: Where It Stands Today

Will the Leaning Tower of Pisa give way to gravity? In this interview from the NOVA Web site, engineer John Burland relates the difficult job of saving the tower.

Life's Grand Design

Are nature's complex forms evidence of "intelligent design"? In this Evolution essay, biologist Kenneth Miller explains how the processes of evolution account for complex structures such as the human eye.

Life's Little Essential: Liquid Water

Why is water necessary for life? Why is it the best and possibly only liquid to do the job? This illustrated essay from NOVA Online answers these questions, explaining why planetary scientists are on the lookout for water elsewhere in the solar system.

Life Stages Cards

All animals develop and grow over time. The animals in this document undergo one of the most dramatic developmental processes known: metamorphosis. See if you can place the developmental stages in their proper order.

Mike Novacek: Fossils in the Gobi

Biologist Mike Novacek discusses his discovery of mammal fossils in the Gobi Desert and what we can learn from them. From Evolution: "Extinction!"

Mitochondria

Often referred to as the powerhouses of the cell, mitochondria provide the energy that powers nearly every cellular process. This essay by John Ross describes in detail the structures and functions of these amazing organelles.

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Mitochondria Functions and Training

This essay by Owen Anderson describes the effects of physical exercise on the number and function of mitochondria inside muscle cells.

Molecular Clocks: Proteins That Evolve at Different Rates

From The Human Evolution Coloring Book by Adrienne Zihlman, four different proteins from humans and horses are compared in this graphic and article, and the reasons each protein evolves at its own characteristic rate are discussed. Each protein is useful for measuring evolutionary change over a different time scale.

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Molecular Level of Genetics

Get down to the molecular nitty-gritty of DNA replication and protein synthesis in this article by Dennis O'Neil.

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More on Galileo's Big Mistake

Even great scientists make mistakes! This illustrated essay from the NOVA Web site looks at Galileo's theory of the tides, which, while well thought out, was wrong.

Nature vs. Nurture Revisited

Which dictates our existence -- our genetic makeup or the environment we grow up in? Kevin Davies offers an update on this long-standing debate, from the NOVA: "Cracking the Code of Life" Web site.

Nuclear Blast Damage

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

Nuclear Reaction: Searching for Safety

This text excerpted from Beyond Engineering: How Society Shapes Technology by Robert Pool and reprinted on the FRONTLINE Web site looks at the impact of nuclear power.

On Human Cloning

Three cloning experts share their opinions in these interviews from the NOVA "18 Ways to Make a Baby." Web site.

Periodic Table of the Elements Chart

This downloadable periodic table of elements, produced for Teachers' Domain, provides easy, transportable access to a wealth of chemical information, including the oxidation state number of each element.

Periodic Table of the Elements essay

This essay, written for Teachers' Domain, describes the foresight and pattern recognition that Russian chemist Dmitri Mendeleyev used to develop the modern periodic table of elements.

Projected Sea Level Rise

Climate change is affecting our oceans in more ways than one. Explore how climate change is affecting sea levels.

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Pulsars: Little Green Men

The story behind Jocelyn Bell's role in the discovery of pulsars is told in this colorful, comic-book-style resource from A Science Odyssey Web site.

Pyrotechnically Speaking

Meet chemistry professor Dr. John Conkling in this interview from the NOVA Web site and learn why fireworks are his passion.

Quantum Mechanical Atom

This illustrated essay, written for Teachers' Domain, describes the orderly arrangement of electrons around the nucleus of an atom and explains how to determine each element's configuration based on the number of electrons it has.

Record of Time

Enter the exciting world of dating ... fossil dating, that is. From Record of Time by anthropologist Dennis O'Neil.

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Relativity and the Cosmos

This illustrated essay from the NOVA Web site introduces the basic concepts of Einstein's General Theory of Relativity and what we know about cosmology as a result.

Sagan on Time Travel

Astronomer Carl Sagan discusses the possibility of time travel in this audio-enhanced interview from the NOVAWeb site.

Seahorse Basics

This diagram from the NOVA: "Kingdom of the Seahorse" Web site reveals some of the more remarkable traits of this enigmatic creature.

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Sea life is troubled by noise

This article from Science a GoGo describes the risks that increasing noise pollution in ocean waters may pose to the creatures that live there. Once you read it, you'll never tap on a fish tank again!

Sound Waves Underwater: Experiment with Sonar

This animation from the NOVA Web site describes how sonar uses sound waves to "see" underwater.

Stem Cell Debate

This essay from the NOVA "Life's Greatest Miracle" Web site explores the debate over the use of embryonic stem cells in scientific research.

Stories in the Ice

Take a journey back through time, using ice cores to learn about the Earth's climatic history. From the FRONTLINE/NOVA: "What's Up with the Weather?" Web site

Stories in the Ice

Take a journey back through time, on the NOVA/FRONTLINE Web site, using ice cores to learn about Earth's climatic history, including evidence of global warming and nuclear activity.

String Theory: A Theory of Everything Essay

In this essay from the NOVA Web site, string theorist Brian Greene introduces the basic ideas behind string theory and how it might help us better understand the universe.

String Theory: Elementary Particles

This illustrated essay from the NOVA Web site looks at the fundamental forces and particles that make up all matter.

Ted Daeschler and Neil Shubin: Early Tetrapod Fossils

In this transcript of an interview filmed for Evolution: "Great Transformations," Ted Daeschler and Neil Shubin describe the discovery and significance of some of their key fossil finds.

Tidal Curiosities

This illustrated essay from the NOVA Web site answers questions about irregularities in the tides.

The Transforming Leap, from Four Legs to Two

John Noble Wilford, a New York Times science writer, outlines various hypotheses on the origin of bipedalism.

Understanding Gene Testing

In this article by the National Cancer Institute and the National Center for Human Genome Research, find answers to your questions about genetic testing.

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Viewpoints: Harvest of Fear

What do the experts say about genetically modified (GM) foods? Read these interview excerpts from the FRONTLINE/NOVA: "Harvest of Fear" Web site to find out.

Water Planet: How the Water Cycle Works

The climate change-induced animations produced by KQED, are designed to illustrate changes to the water cycle that may occur over many years.

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Wave of the Future

This media-rich essay from NOVA Online describes the challenges involved in installing a warning system for tsunamis in the Indian Ocean.

Whale and Human Ears

What do whale ears look like? You might be surprised! These two versions of this diagram -- one with the anatomical parts labeled and one that students can label themselves -- compare the anatomy of a whale ear to that of a human ear. From Marine Biology: Environment, Diversity, and Ecology by David Lerman

Whales in the Making

This graphic from Evolution, traces the evolution of whales from land-dwelling mammals to the aquatic creatures we know today.

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