How does your body know when to present an immune response? Viewers observe how antigen presentation triggers the response and how this treatment helps attack viruses before they spread. The video also discusses the challenges of...

Even today's stem cells have a history—and it's more than 30 years old! Learn how stem cell lines grow in a lab. Observe the various experiments completed to determine how cells grow in human embryos.

Zebrafish find popularity among aquarium owners for their beauty and biologists for their unique abilities. Biologists discovered zebrafish have the ability to regenerate damaged hearts. Use the video to observe and understand this...

The narrator of a short animated video asks viewers to consider how they are just one link in a great chain of life that extends all the way back through time to the first single-cell organisms.

Many define biology as the study of life but can't agree on a definition of life. Trying to explain all of the domains and subdomains of biology seems a bit easier than defining life. See a full map of the topics covered by the general...

The foot bone connects to the leg bone, but how? Learn about how neurons grow in the proper direction thanks to signalling. Observe what happens when they encounter a repulsive ephrin signal and the correction process that takes place.

Almost half of the global population infected with HIV cannot afford treatment. To better understand this devastating disease, young scientists observe the life cycle of HIV.  Through animation, they see the cell infection,...

Protease inhibitors currently treat HIV and hepatitis C, but in the future, might also be used to treat some cancers. Viewers learn how HIV spreads in the body and then observe what happens after the introduction of a protease...

The first AIDS cases in the United States were reported in June of 1981. AIDS quickly became an epidemic soon and the lack of a treatment or cure caused fear in the entire population. Viewers observe a geographical representation of the...

AZT, developed in the 1960s to treat cancer, actually treats HIV as well. Viewers observe how AZT blocks the reverse transcriptase of HIV. Then they see what happens when the virus mutates to be immune to AZT.

At what point in the fertilization process do stem cells turn into an embryo? Viewers observe the development of an embryo from egg to fertilization to development into a fetus. The narrator stresses the role of cell division,...

Cell division, cell expansion, and cell growth all take place in the cytoplasm exclusively. Young biologists learn about the role of cytoplasmic factors in cell development through and animated video.

The sun heats Earth's surface unevenly, causing crazy weather patterns around the globe.  A NOVA video describes the resulting changes in air pressure, temperature, humidity and their impacts on weather. It connects the concepts to...

Approximately 2,000 thunderstorms happen simultaneously across the planet at any given time—that's a lot! Beginning with how clouds form, NOVA describes the conditions needed for storms to develop, and highlights the three factors that...

It's a question economists, anthropologists, and sociologists have asked themselves since the first regional lines were drawn in the sand. Are there common factors that destine one country to thrive and another to struggle? An...

Did you realize cells become restricted in the types of cells they produce as embryos develop? Stem cells might become anything, but late state cells can only become the specialized cell based on their locations. A captivating video does...

If Earth didn't have clouds, the global temperature would be at least 22 degrees Fahrenheit warmer. Viewers examine the importance of clouds on temperature, climate, and global warming. The video describes the current impact of clouds...

Scientists categorize clouds by both height and shape since both traits impact the weather independently. Viewers fly high to learn about the characteristics of each type of cloud. NOVA explains the composition of clouds, the atmospheric...

Why do big storms spin as they travel? As Earth spins, the movement of air and water change. Viewers observe the Coriolis effect on paper airplanes, water, and even hurricanes—and find the effect is everywhere!

Did you know animals hibernate all around the world, even in the deserts and tropical rain forests? How do these animals reach extreme body temperatures and undergo a decreased heart rate that would be deadly to non-hibernating animals?...

Biogeography is the study of the geographical distribution of plants and animals. NOVA's Evolution Lab explains how organisms on different continents can be so closely related. The resource discusses the processes that bring life from...

Have you been shaped by evolution? A short video introduces the idea of evolution through examples of natural selection, reproduction, traits, and more. The video exists as a small part of a series from the NOVA Evolution Lab.

What happens to the CO2 emitted into the air by volcanoes? Scientists discovered it is removed through a series of chemical reactions, as discussed here. Through an animated diagram and chemical reaction equations, viewers learn about...

In humans, the rate of mutation from one generation to the next is between 100 and 200 mutations. Discover the role of DNA mutation in evolution with an enriching lab activity.