Search ALEX...

What is light? That is something that has plagued scientists for centuries. It behaves like a wave and a particle. Is it both? In this episode of Crash Course Physics, Dr. Shini introduces the idea of quantum mechanics and how it helps us understand light. Also, there's this thing called the ultraviolet catastrophe.

Severe storms can really wreak some havoc on the Earth. Thunderstorms bring lightning and strong winds, but tornadoes, hurricanes, and blizzards can cause even greater destruction.

The classroom resource provides a slide show that will describe types of severe weather that can occur and their possible impacts on Earth. There is also a short test that can be used to assess students' understanding.

Students use the engineering design process to create a magnetic train in this lesson plan created by teacher Heather Rizzo.

The classroom resource provides a video that will describe a variety of animal adaptations. After utilizing this resource, the students can complete the short test to assess their understanding.

As with most things in chemistry (and also in life), how a gas moves is more complex than it at first appears. In this episode, Hank describes what it means when we talk about the velocity of a gas. To understand gas velocity, we have to know what factors affect it and how. Hank also teaches you about effusion, diffusion, and concentration gradients, before showing off a cool experiment that physically demonstrates the things you have just learned. Sound exciting enough for you? Let's get started.

A mixture contains two or more substances that retain all their original properties and can be physically separated. Mixtures can be homogenous or heterogeneous.

The classroom resource provides a video that will describe the two types of mixtures. There is also a short test that can be used to assess students' understanding.

In this lesson, students will be able to explain that snap cubes or other objects can be used as models of atoms. Students will also be able to explain that atoms can be rearranged to make different molecules. 

Students see an animation showing that the things around them are made of atoms and molecules. Students are given white, red, blue, and black cubes that represent hydrogen, oxygen, nitrogen, and carbon atoms. Students are guided to take atoms apart, rearrange them, and put them together again in different ways to make six different molecules. Students also see a fun molecule-making game that they can try.

This resource presents a short slideshow about different weather instruments. This slideshow could serve as an introduction to the purpose of these instruments prior to students measuring weather variables themselves. After utilizing this resource, the students can complete the short test to assess their understanding.

In this video, Hank discusses different kinds of solids out there and talks about why they're all different and have different properties. Today, you'll learn about amorphous and crystalline solids, types of crystalline solids, types of crystalline atomic solids, properties of each type of solid, and that the properties depend on the bond types.

Energy does not change, and that means it is constant. When one object applies force to another, the energy becomes an equal and opposite reaction.

The classroom resource provides a video that will explain Newton's Third Law of Motion. This resource can provide background information for students before they conduct their own demonstrations. There is also a short test that can be used to assess students' understanding.

In this lesson, students will be able to plan and carry out an investigation to identify which two of the three ingredients in baking powder react to produce a gas when water is added. Students will be able to explain that mixing substances can cause a chemical reaction that results in the formation of a new substance. Students will also be able to explain that substances react in characteristic ways and that the way a substance reacts can be used to identify the substance. 

In this series of activities, students learn about how microbial diseases are transmitted and start to think about who is involved in a community response to an outbreak of an infectious disease. Students use the case of John Snow to learn how epidemiologists can use maps to locate the source of an outbreak and map a hypothetical pathway of disease transmission for a particular disease. This lesson is part of the Menacing Microbes unit.

A wounded seal swims slowly toward shore, while a shark patrols the water nearby, looking for an easy target. In this interactive feature from NOVA, understanding the six senses sharks use to locate and capture their prey may give you the edge you need to help the seal reach land safely.

Players are challenged to complete a series of missions to photograph mountain plants and animals in the Canadian Rockies, in this interactive game from PLUM LANDING™. Through the clues that Plum provides, players learn about mountain ecosystems, the plants and animals living there, and how they are adapted to mountain life. 

In this lesson, students will see a small piece of ice melt on an aluminum surface. Students will explain the energy transfer and molecular motion which cause the change in state from a solid to a liquid. Students will see and discuss animation of ice melting and compare the state changes of water to the state changes of other substances. They will also investigate the sublimation of dry ice through a teacher demonstration, or video if dry ice is not readily available.

Students will be able to explain on the molecular level the process of heat transfer and molecular motion that causes a solid to melt to form a liquid. Students will also be able to explain how the arrangement of water molecules is different from most other substances when it changes state from a solid to a liquid.

Steve Trash teaches kids about science with fun and magic. The show is filmed in Alabama.

In this episode, Steve shares his knowledge about some of the coolest creatures on the planet: birds. Why are there so many different kinds of birds? Why so many colors? How do they fly? Then he shares one of his favorite ideas to think about: what makes a resource renewable or not renewable?

In this lesson, students will observe three household liquids stacked on each other and conclude that their densities must be different. They will predict the relative densities of the liquids and then measure their volume and mass to see if their calculations match their observations and predictions.

Students will be able to determine whether a liquid will sink or float in water by comparing its density to the density of water.

Students investigate the impacts of plastics on marine organisms in different marine ecosystems. They construct a food web for an assigned ecosystem, using it to illustrate the principle of biomagnification visually. Students draw on evidence presented in this lesson and in the previous lesson, Plastics, Plastics, Everywhere, to justify an argument about whether plastic pollution affects humans as well. This lesson is part of the Plastics: From Pollution to Solutions unit.

When you flip a light switch on and off, you are closing and opening a circuit. A circuit is a path that electricity follows. This interactive helps students learn more about circuits.

Use science inquiry to predict and investigate forces and motion to help rescue Ruff's plushie from the penguins' ice rink in this sports science game from The Ruff Ruffman Show. Students will apply the right amount of force on a cannon to move the plushie into the target space. 

This resource is part of The Ruff Ruffman Show Science Collection.

They're an important part of the ecosystem. They prevent disease and clean up carrion. Yet, they're also a nuisance to homeowners and a threat to livestock. Their population has recovered and grows at an incredible rate. At what point can we say that there are too many black vultures in America?

This informational material will apply a precalculus concept--limits of functions--to an environmental science issue--how biological and physical changes within an ecosystem can affect the population growth of a species. There are additional links provided for students to explore more about this issue.