Explore the innovative ways countries are revolutionizing farming to ensure we can feed humanity in a way that works with the environment. About 10,000 years ago, humans began to farm. This agricultural revolution was a turning point in our history and enabled the existence of civilization. Today, nearly 40% of our planet is farmland. Spread all over the world, these lands are the pieces to a global puzzle we’re all facing: in the future, how can we feed every member of a growing population a healthy diet? Brent Loken investigates.

Explore how a capacitor works! Change the size of the plates and add a dielectric to see how it affects capacitance. Change the voltage and see charges built up on the plates. Shows the electric field in the capacitor. Measure voltage and electric field.

This short video and interactive assessment activity is designed to teach second graders about capacity comparison problems with illustrations - word problems.

This short video and interactive assessment activity is designed to teach fourth graders about finding the amount of water with illustrations and calculations (metric units).

This short video and interactive assessment activity is designed to teach third graders an overview of capacity IIi (metric units).

This short video and interactive assessment activity is designed to teach second graders about capacity problems with illustrations - word problems.

Students are presented with a short lesson on the difference between cohesive forces (the forces that hold water molecules together and create surface tension) and adhesive forces (the forces that causes water to "stick" to solid surfaces. The interaction between cohesive forces and adhesive forces causes the well-known capillary action. Students are also introduced to examples of capillary action found in nature and in our day-to-day lives.

As part of a (hypothetical) challenge to help a city find the most affordable and environmentally friendly way to clean up an oil spill, students design and conduct controlled experiments to quantify capillary action in sand. Like engineers and entrepreneurs, student teams use affordable materials to design and construct models to measure the rate of capillary action in four types of sand: coarse, medium, fine and mixed. After observing and learning from a teacher-conducted capillary tube demonstration, teams are given a selection of possible materials and a budget to work within as they design their own experimental setups. After the construction of their designs, they take measurements to quantify the rate of capillary action, create graphs to analyze the data, and make concluding recommendations. Groups compare data and discuss as a class the pros and cons of their designs. Pre- and post-evaluations and two worksheets are provided.

In which John Green teaches you about capitalism and socialism in a way that is sure to please commenters from both sides of the debate. Learn how capitalism arose from the industrial revolution, and then gave rise to socialism. Learn about how we got from the British East India Company to iPhones and consumer culture in just a couple of hundred years. Stops along the way include the rise of industrial capitalism, mass production, disgruntled workers, Karl Marx, and the Socialist Beard. The socialist reactions to the ills of capitalism are covered as well, and John discusses some of the ideas of Karl Marx, and how they've been implemented or ignored in various socialist states. Plus, there are robots!

In which John Green teaches you about the Vereenigde Oostindische Compagnie, doing business as the VOC, also known as the Dutch East India Company. In the 16th and 17th centuries, the Dutch managed to dominate world trade, and they did all through the pioneering use of corporations and finance. Well, they did also use some traditional methods like violently enforced monopolies, unfair trade agreements, and plain old warfare. You'll learn how the Dutch invented stuff like joint stock corporations, maritime insurance, and futures trading. Basically, how the Dutch East India Company crashed the US economy in 2008. I'm kidding. Or am I?

Capt. Charles Moore of the Algalita Marine Research Foundation first discovered the Great Pacific Garbage Patch -- an endless floating waste of plastic trash. Now he's drawing attention to the growing, choking problem of plastic debris in our seas. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 7-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

Derek Jeter discusses what being the captain of the New York Yankees meant to him.

Students create and use pinhole cameras to understand how artists use and manipulate light to capture images in photographs. They shoot and develop photographs made with pinhole cameras. They compare and contrast a nineteenth-century image, photographs taken with a pinhole camera, and pictures created with a digital camera or camera phone.

Students create pinhole cameras to understand that light travels in a straight path. They describe the lines and shapes in a nineteenth-century photograph of a building and then use their pinhole cameras to trace the architecture of their school building.

Students create pinhole cameras to learn how artists manipulate light to make photographs. They describe and analyze a nineteenth-century photograph and use their cameras to capture the architecture of their school or other buildings.

Students will examine the sculpture "Rearing Horse" by Adriaen de Vries. They will then draw and sculpt animals from life, trying to capture motion frozen in a moment.

In the exploration of ways to use solar energy, students investigate the thermal energy storage capacities of different test materials to determine which to use in passive solar building design.

This art history video discussion examines Caravaggio's "Calling of St. Matthew," oil on canvas, c. 1599-1600 (Contarelli Chapel, San Luigi dei Francesi, Rome).

This art history video discussion examines Caravaggio's "Crucifixion of St. Peter", oil on canvas, 1601 (Santa Maria del Popolo, Rome).