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!

In this activity about light and perception, learners create and observe moire patterns. These special patterns, which appear when two repetitive patterns overlap, can also be used to help learners understand wave interference. Learners will use various objects including pocket combs, window screens, and transparencies to investigate moire patterns in different ways.

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.

In this activity about electricity and magnetism, learners examine what happens when a magnet exerts a force on a current-carrying wire. Using a simple device, learners discover that when an electrical current flows through a magnetic field, a force is exerted on the current and this force can be used to make an electric motor. Learners will experiment to find out what happens when they reverse the direction of current flow. They will also discover a mathematical tool called the "right-hand rule."

Lets us look over the shoulders of scientists and glimpse the often-unseen moments of investigation. Take virtual field trips to eight observatories -- Arecibo, where astrobiologists search for signs of life beyond the solar system; Las Cuevas, a research station in Central America's largest remaining rainforest; and others. See interviews, photos, and broadcasts that explore the origins of matter, the universe, and life itself.

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.

In this activity, learners explore the question "What is paper?" Learners discover the processes and materials required to make paper while experimenting with different recycled fibers and tools.

In this activity about light and reflection, learners use a special device called a Mirage Maker䋢 to create an illusion. What they perceive as an object is really an image in space, created by two concave mirrors. Learners will be surprised when they try to grab the object on the mirror and there's nothing there! Activity includes a light-ray diagram to help explain how the image is created.

In this online activity, learners experience the thrill of pickle making, and explore how a cucumber becomes a pickle. In this "virtual kitchen," leaners discover that pickling takes practice to determine the best recipe (or conditions) for pickling cucumbers. These conditions include room temperature and amount of salt. Use this activity to help learners explore the science of cooking.

In this activity, students observe fluid motion and the formation of convection cells as a solution of soap and water is heated. This procedure can be performed as a demonstration by the teacher, or older students can conduct the experiment themselves. A list of materials, instructions, and a description of the convective process are included.

In this activity, learners construct a device out of a piezoelectric igniter, like those used as barbecue lighters. Learners use the device to remotely start current flowing in a simple series circuit containing a small electric fan.

In this activity related to light and perception, learners use a pinhole in an index card as a magnifying glass to help their eye focus on a nearby object. Learners will also discover that because this magnifier limits the amount of light that reaches their eye from the object, the pinhole makes the object appear dimmer. Learners are encouraged to explore using pins and needles with different diameters to make different-sized holes in index cards to see how this affects the image. They can also try forming a pinhole by curling their index finger.

In this activity, learners work in groups to determine the mass and volume of four samples: glass marbles, steel washers or nuts, pieces of pine wood, and pieces of PVC pipe. Learners then plot the data points on a large class graph of mass vs. volume to discover that data points for a particular material form a straight line, the slope of which gives the density of the material.

In this activity, learners explore how polarizing sunglasses can help diminish road glare. By rotating a pair of polarizing sunglass lenses or other polarizing materials, learners will discover that some angles are better at reducing glare than others. Learners observe light from the sky, reflected from a mirror, or reflected from the surface of a pond. Use this activity to introduce learners to principles of light and polarization.

In this activity, learners explore their eye pupils and how they change. Learners use a magnifying glass, mirror, and flashlight to observe how their pupil changes size in response to changes in lighting. Learners also experiment to determine how light shining in one eye affects the size of the pupil in their other eye. This resource guide includes background information about pupils and why they change as well as information related to emotional stimuli, involuntary reflexes, and photography.

In this group activity, learners use some common objects and work together to simulate the Coriolis effect. During the challenge, learners make predictions and test different scenarios. This resource includes background information about the Coriolis effect and helpful hints.

In this activity, learners explore how different deodorants work. Learners treat agar plates with different types of deodorants and compare the bacteria growth on the plates to the control sample.

In this activity, learners explore electronics and motion by making a Scribbling Machine, a motorized contraption that moves in unusual ways and leaves a mark to trace its path. It's made from simple materials and is based on the idea of motion created by an offset motor. Try using harvested motors and switches from discarded toys and electronics to make your Scribbling Machine - this not only keeps costs down, but is a playful and inventive way to explore how everyday objects work. To take the activity further, you can also incorporate PicoCrickets to make your Scribbling Machine more intelligent and to explore computers.

In this activity you'll see how the sun's tilt on its axis changes the length of shadows. For example, why is your shadow longer in winter than in summer? It's easy to see the answer if you have a "sun" and an orbiting "earth" to demonstrate. Like many other ancient people, the ancient Chacoans used the annual changes in shadows to measure the passage of time and the change in seasons. You can too!

In this quick optics activity, learners use a dim point of light (a disassembled Mini MagLite and dowel set-up) to cast a shadow of the blood supply in their retina onto the retina itself. This allows learners to see the blood supply of their retina and even their blind spot. Learners are encouraged to wear eye protection.