Physiology

Could window panes be made out of wood?

Do you know what happens to water when it evaporates?

Strap on your shoes and join Mr.

Team up with Ackerley the Acanthostega to travel back 66 million years to the Tertiary and Quaternary periods of prehistoric Earth, when mammals came to dominate the planet.

Follow Ackerley the Acanthostega through the Cretaceous period, 145 to 66 million years ago, when the mightiest dinosaurs stalked the planet.

Come along with Ackerley the Acanthostega to visit the Triassic and Jurassic periods, 203-145 million years ago.

Join Ackerley the Acanthostega and travel back in time 4,500 million years to the Precambrian period, when our planet first formed.

Scientists have identified at least 100 million pieces of space debris-from paint chips to nonoperational zombie satellites-floating in Earth's orbit.

What do giant squids, mantis shrimp, and fireflies have in common?

What is the longest bone in your body?

Where is the Solar System's biggest mountain?

Do you know what happens to water when it evaporates?

Could window panes be made out of wood?

Strap on your shoes and join Mr.

Flowering plants, cone-bearing plants, ferns, and mosses make up the four main plant groups.

Carbon is everywhere.

Which works better to haul a pumpkin-a lever or wheels and axles?

Which makes it easier to lift a large toy-a wedge or wheels and axles?

Is it easier to move ice with a lever or a screw?

Is it easier to lift a bag full of toys with an inclined plane or a pulley?

These kids are playing a game, trying to move a person with a simple machine.

Is it easier to move heavy box with an inclined plane or wheels and axles?

The octopus spies a nice, tasty mantis shrimp.

Team up with Ackerley the Acanthostega to travel back 66 million years to the Tertiary and Quaternary periods of prehistoric Earth, when mammals came to dominate the planet.

Come along with Ackerley the Acanthostega to visit the Triassic and Jurassic periods, 203-145 million years ago.

Join Ackerley the Acanthostega and travel back in time 4,500 million years to the Precambrian period, when our planet first formed.

Follow Ackerley the Acanthostega through the Cretaceous period, 145 to 66 million years ago, when the mightiest dinosaurs stalked the planet.

What animal was here?

Have you ever solved a tricky puzzle?

Have you ever built a cool science project?

Have you ever wondered how the universe began?

How did our knowledge of matter, gravity, and electricity develop over time?

How did our knowledge of cells, heredity, evolution, ecosystems, and photosynthesis develop?

Sunlight, air, water, and minerals help keep plants alive.

A plant can form fruit and seeds when it is pollinated.

Plants have roots, stems, leaves, and sometimes flowers.

Roots help keep plants alive.

Some flowers are able to produce seeds or fruit without getting pollen from another plant.

The flower is the part of a plant that makes seeds or fruit.

Many insects drink nectar and collect pollen from flowers, and in the process they help plants reproduce.

Some plants need to have pollen spread from one plant to another flower in order to reproduce.

Many plants depend on animals to help move pollen around so that the plants can reproduce.

After the 1986 Chernobyl nuclear explosion in Ukraine, scientists believed radiation had created a vast and barren wasteland in which life could never resurface.

The octopus spies a nice, tasty mantis shrimp.

What animal was here?

Does the universe circle around Earth?

Do your eyes send out light like headlights?

Do bulls get angry when they see the color red?

Robots help us understand our universe.

Crackle!