Students simulate operating an iron mine, from choosing property to writing an environmental impact statement to setting up the mining operation. Chocolate chip cookies (with the chocolate chips representing iron ore) are used for this experiment. Students are challenged to operate the most profitable and environmentally sound mine they can.

In this video David solves a few exmaple problems involving concave and convex mirrors using the mirror equation and magnification equation.

This is an online exhibit about color perception. Learners set a random background color and then try to mix red, blue, and green light to match. Although this is a perception activity, it also demonstrates the difference between mixing colors of light and mixing pigments. Why when mixing pigments does the color darken? How does this differ from mixing colored light? Find out here!

STUDENT ACTIVITY - 4th - TXThis is a distance-learning lesson students can complete at home. The student will compare and contrast a variety of mixtures, including solutions, that they can make outdoors. This activity was created by Out Teach (out-teach.org), a nonprofit providing outdoor experiential learning to transform Science education for students in under-served communities.

In this activity, candy models are used to demonstrate the features of the Earth, including its internal structure and layers. Students learn why models are essential in Earth science and answer questions about how their candy models do and do not compare with the actual Earth.

Small molecules are chemicals that can interact with proteins to affect their functions. Learn about the structure and biological functions of various small molecules like sugar and caffeine. Also featured on the HHMI DVD, Scanning Life's Matrix: Genes, Proteins, and Small Molecules. Available free from HHMI.

In this interactive activity from ChemThink, learn about covalent molecules and how the VSEPR theory predicts the shapes of covalently-bonded molecules.

Students will predict bond polarity using electron negativity values; indicate polarity with a polar arrow or partial charges; rank bonds in order of polarity; and predict molecular polarity using bond polarity and molecular shape.

In this two-part activity, learners use everyday materials to visualize one mole of gas or 22.4 liters of gas. The first activity involves sublimating dry ice in large garbage bag. The second activity uses plastic bottles.

This activity was designed for blind learners, but all types of learners can use it to explore the law of conservation of momentum.

A few more examples of exponential decay. Practice calculating k from half-life, and calculating initial mass. Created by Sal Khan.

David explains some of the common misconceptions in dealing with Newton's Third Law. He also shows how to correctly and reliably identify Third Law force pairs. Created by David SantoPietro.

Clarification of, and more thoughts on, the Bernoulli's equation example problem where liquid exits a hole in a container. Created by Sal Khan.

See how there's actually constructive (rather than just destructive) interference at some points on the screen. Created by David SantoPietro.

This video segment adapted from NOVA relates the dramatic story of vulcanologists trying to predict the timing of the cataclysmic eruption of Mount Pinatubo in the Philippines.

Some examples of using the thin lens equation with multiple lenses. Created by David SantoPietro.

Carla Dove is the program manager at the Feather Identification Lab at the Smithsonian. Learn how she deciphered the mystery of an airplane striking a deer - at 1500 feet in the air.

Pilot and TV Personality Ariel Tweto shares advice on the importance of seeking out new experiences through traveling, working hard, and meeting people of different backgrounds.

Build your own system of heavenly bodies and watch the gravitational ballet. With this orbit simulator, you can set initial positions, velocities, and masses of 2, 3, or 4 bodies, and then see them orbit each other.

Join a group of middle-school students on a visit to a laboratory at the Massachusetts Institute of Technology, where they experiment with "mystery mud" and learn about the relationships between magnetism, particle motion, and changes in the state of matter.