City Farm

In this interactive game from WGBH, players learn about sustainable practices by growing crops, protecting them against unforeseen problems, and determining how best to conserve resources.

The Civil Rights Movement in America, 1945-1975

This interactive timeline provides a chronological and geographic view of the events of the Civil Rights era and its aftermath.

Climate Change and Human Health

Learn how global climate change affects human health in this interactive activity adapted from "A Human Health Perspective: On Climate Change" by the National Institute of Environmental Health Sciences.

Climate Wisconsin: Ice Cover

Ice cover data and long term trends for Lake Mendota and Lake Mendota in Madison, WI can be explored in this interactive resource produced by the Wisconsin Educational Communications Board.

Climate Wisconsin: Temperature Change

Investigate observed and projected average annual temperature change in Wisconsin in this interactive resource produced by the Wisconsin Educational Communications Board.

Closed-Loop Systems

This interactive activity adapted from the Wisconsin Online Resource Center explores the processes, controls, and components that make up a typical closed-loop system used in automated manufacturing.

Cloud Types

This interactive resource, adapted from NASA's S'COOL Project Tutorial, explains how you can classify and identify various types of clouds.

Clues from Past Climates

In this interactive produced by ThinkTV, learn how scientists discover clues to past climates that lie hidden in the natural environment, as well as in some surprising historical documents.

Coastal Geological Materials

This interactive resource adapted from the National Park Service describes the different kinds of sediments that make up coastlines, with a focus on the variety in color, size, and sorting.

Coastal Geological Processes

This interactive resource adapted from the National Park Service describes the many forces that affect shorelines, including tides, weathering, erosion, and deposition.

Collisions on an Air Track

In this interactive activity adapted from the University of Toronto, observe the effect of mass on momentum in elastic and inelastic collisions.

Compare and Contrast Warm and Cold Fronts

This visualization from McDougal Littell/TERC visualizes the movement of warm and cold fronts and the cloud types that are generated as a result.

Compare the Poles

Explore the defining features of the Arctic and the Antarctic in this interactive activity adapted from the Woods Hole Oceanographic Institution.

Comparing Fractions: Bubble Gum Blowing Contest

In this interactive activity adapted from Anneberg Learner’s Teaching Math Grades 3–5, compare fractions on number lines to determine which class of students wins bubble-gum-blowing contests.

Compost Office

This interactive activity from Keep America Beautiful, Inc. uses illustrated text and a game to explain why it is important to compost, the science involved, and the perfect recipe for decomposition.

Computer Networks

This interactive activity adapted from the Wisconsin Online Resource Center describes types of computer networks and how they function.

Construct an Aqueduct

Think like an engineer and build an aqueduct in this interactive activity from the NOVA Web site.

Continental Divide: The Breakup of Pangaea

Examine geological evidence found in fossils, rock deposits, and ancient mountains that supports the theory of continental drift in this interactive activity adapted from the Exploratorium.

Cooking with Sugar

Find out about the chemistry of candy and how sugar reacts at different temperatures to become fudge, caramel, lollipops, and more in this interactive activity adapted from the Exploratorium.

Coral Reef Connections

Dive in and explore what makes this beautiful world so fragile. In this Evolution Web feature, discover how coevolution has shaped the ecological relationships among reef creatures.

Covalent Bonding

This interactive activity from ChemThink takes a closer look at a covalent bond—how it is formed and how the sharing of two electrons can keep atoms together.

Cow's Eye Dissection

In this interactive activity adapted from the Exploratorium, watch videos of a cow eye dissection and see how an eye works.

Crack Hacker's Safe

In this Cyberchase interactive, select the color, number, and shape of the next term in the pattern.

Create a DNA Fingerprint

Learn DNA profiling, the technique police use to catch the guilty and free the innocent. From NOVA: "The Killer's Trail" Web site.

Creepy Crawlies

This interactive feature from the NOVA: "Odyssey of Life" Web site explores the often unwitting relationship we share with the billions of organisms that reside in our bodies and in our homes.

Crocodiles! Clickable Croc

This interactive feature from the NOVA "Crocodiles!" Web site details some of the characteristics that have enabled crocodiles to thrive for 200 million years.

Accessibility features: Long Description

The Dam Challenge

In this interactive activity from the Building Big Web site, investigate dams in distress and decide if they should be repaired, removed, or left alone.

Dance of Development

Watch the "dance" of development as a zebrafish egg divides and differentiates on its way to becoming an embryo in this interactive activity adapted from the Exploratorium.

Dances with Bees

This interactive feature from the NOVA "Tales from the Hive" Web site explores the methods honeybees use to communicate to their hivemates the location, quantity, and quality of nearby food sources.

Darwin's Diary

Delve into the private thoughts of a reluctant revolutionary in this Evolution Web feature.

De-Twinkling the Stars

Find out why stars twinkle and adjust a telescope to sharpen a star's image in this interactive activity adapted from NASA.

Deep-Sea Bestiary

This interactive from NOVA describes the physical and behavioral traits of some of the least-known and most unlikely creatures on Earth.

Deep Time

This interactive timeline from Evolution offers a visual representation of the major geological changes, transformations, and extinction episodes in the 4.6-billion-year history of Earth.

Deep Time

Explore 4 billion years of life on Earth and discover major transformations, geological changes, and extinction episodes in this Evolution Web feature.

Deforestation in Bolivia

This visualization adapted from NASA features two satellite images from 1984 and 2000 that show the dramatic deforestation of the Bolivian rainforest.

Design a Liquid Fuel Rocket Engine

Learn about rocket engines, and then design and launch a liquid fuel rocket in this interactive activity adapted from NASA.

Design an Ion Engine

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

Design: Building a House

This collection of images follows the process of building a house from cutting the trees and making the bricks to finishing construction.

The Design Process

This video resource, excerpted from DESIGN SQUAD, illustrates each step of the engineering design process.

Accessibility features: Caption

The Disappearing Aral Sea

This visualization adapted from NASA features satellite images showing how more than 60 percent of the Aral Sea has disappeared during the last 30 years.

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 Antarctica

Take a guided tour of Antarctica by watching brief video segments of its landscape and wildlife in this interactive activity adapted from the British Antarctic Survey.

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.

DNA Extraction

This interactive activity adapted from the University of Nebraska's Plant and Soil Sciences eLibrary illustrates how DNA, which is normally locked inside of cells, is extracted from living tissue.

DNA Libraries

This interactive resource adapted from the Dolan DNA Learning Center explores the different types of DNA libraries used to store and access genetic information.

DNA Sequencing

This interactive activity adapted from the Dolan DNA Learning Center looks at two techniques used to sequence DNA: the Sanger method and an automated process based on the Sanger method.

DNA Workshop

How does DNA perform those all-important functions of replication and protein synthesis? This interactive feature from the A Science Odyssey Web site will help you explore and understand the secrets of DNA.

Documenting Glacial Change

This collection of comparative glacier images adapted from the National Snow and Ice Data Center shows substantial changes in five Alaskan glacier positions over periods of 60 to 100 years.

Dolly Garza: A Tlingit and Haida Scientist

In this interactive resource adapted from Raven Radio/KCAW, listen to biologist Dr. Dolly Garza as she explores the sea otter population of Sitka, Alaska, from the perspectives of her tribal heritage and her Western education.

The Dome Challenge

In this interactive activity from the Building Big Web site, think like an engineer and use your knowledge of dome design to match the right type of dome to the right location in a fictitious city.