In this video segment adapted from NOVA scienceNOW, MIT engineer Dava Newman is working to replace today's bulky, inflated space suits with a radical, sleek design that may one day allow astronauts to walk easily on Mars.

This module provides an overview of the nitrogen cycle and the chemical changes that govern the cycle.

This video segment adapted from FRONTLINE looks at nuclear fission as an energy source that can be used to generate electricity.

Using the ratio of neutrons to protons to figure out of a nucleus will be stable or radioactive. Created by Jay.

Object Image and Focal Distance Relationship (Proof of Formula). Created by Sal Khan.

This video segment produced for Teachers' Domain features a time-lapse video of clouds forming, changing, and moving across the sky.

This brief video segment produced for Teachers' Domain features time-lapse video of a sunrise and a sunset.

This video segment adapted from Shedding Light on Science illustrates how light changes speed, and thus direction, in a process known as refraction.

This lab crushes an aluminum can to investigate states of matter and air pressure.

This page is part of NASA's Earth Observatory website. It features text and a scientific illustration to describe how the ocean interacts with the atmosphere, physically exchanging heat, water, and momentum. It also includes links to related data sets, other ocean fact sheets, and relevant satellite missions.

This video segment adapted from NOVA follows the clean-up effort after the 1989 Exxon Valdez oil spill off the coast of Alaska. Also featured is a marsh where an oil spill occurred 20 years earlier; analysis suggests that environmental damage may last for decades.

The purpose of this resource is to observe seasonal migration patterns, feeding habits, and nesting behavior of Ruby-throated Hummingbirds (Archilochus colubris) in North and Central America. All students will learn about hummingbird natural history and ecology. Students will learn how to identify and age male and female Ruby-throated Hummingbirds and to observe migration and feeding behavior. Students will learn how to make connections among hummingbird behavior and weather, climate, food availability, seasonality, photoperiod (day length), and other environmental factors.

This video segment adapted from NOVA explains the origin of the elements and how scientists use unique element profiles to identify supernova types.

This video segment adapted from NOVA follows the Apollo 15 astronauts as they collect samples of ancient rock from the Moon's crust, whose discovery helps lead to a radical new theory about the Moon's origin.

This booklet is meant to engage young children in learning about the Sun, its relationship to the Earth, and to stars. Activities are included that are designed to assist teachers and students in active inquiry.

Users can choose a time in geologic history, select the link, and see what the Earth looked liked in the far distant past. Each map features a brief written description of the events occurring at that time, and a link to additional information on the geologic era or period being shown. There are also maps that show what the Earth might look like in the future, 50, 100, and 150 million years from now.

In this activity, learners build bridges using paper and explore how much weight each bridge design can support. There is an element of surprise, which increases learners' interest in the physics, when they discover just how strong they can make this seemingly flimsy material. This lesson guide includes background information, discussion questions, demonstration ideas and extensions.