Meet the master of compound machines: Rube Goldberg! His wacky contraptions put a whole new spin on the use of simple machines.

Find out how scientists explain our yawns and use the graph to keep track of your family's yawns for a whole day!

Give your student a fun reading page and word search, filled with fun facts all about the Earth's desert ecosystem.

Where is the liver located? Using the diagram as a reference, kids cut out the different parts of the liver from this worksheet and piece them together.

Read about one of Yellowstone National Park's coolest animals, the big horn sheep.

This Earth Day quiz family and friends with this true or false questionnaire. It's all in good, informative, fun!

Did you know that tons of wildlife can thrive in below freezing temperatures? Learn about the polar ocean ecosystem with this fun sheet!

Check out the structure of a bone in this "Inside-Out Anatomy" worksheet.

To learn about muscles, look no further than this Inside-Out Anatomy page.

Explore the life cycle of a pumpkin with your kids with this colorful cut and paste growth chart.

In this physical science worksheet, students will review how to calculate velocity given time and distance and then apply this process to several diverse word problems.

In this "Inside-Out Anatomy" page you can learn about the immune system, the system that keeps us healthy and well.

Use this anatomy worksheet to learn about circulation, and see how nutrients travel to all parts of your body.

Use this worksheet to learn more about the urinary system and see how waste is processed and excreted.

Use this worksheet to learn more about the human reproductive system, and learn more about where we all started.

Learn about the most vital of vital organs in this "Inside-Out Anatomy" worksheet.

Where is the Earth in space? Check out this worksheet that describes where weÃand some of our neighborsÃare in our galaxy.

Learn about the human urinary system with this Inside-Out Anatomy worksheet, which shows how waste is processed and excreted from the body.

Use this "Basic Human Anatomy" sheet to see how blood carries nutrients through your body.

You can check out the cardiovascular system in this worksheet, and better understand how the heart and lveins work with each other.

Earth has many different land and water features—can you recognize them? Test your knowledge with this crossword puzzle for third and fourth graders!

Explore grasslands and their fauna in this thought-provoking worksheet!

Students explore the mechanics of the respiratory system in this life science worksheet for middle school.

Deserts might seem inhospitable to life, but there are actually plenty of animals that can live there!

Explore a tropical rainforest habitat and its inhabitants with this engaging worksheet for third graders!

Determine if certain animals could live in a temperate deciduous forest with this habitat worksheet for third graders!

Why do some desert animals have large ears? Why do others have scales? Learn the answers to these questions and more with this life science worksheet!

Dive into a coral reef ecosystem with this life science worksheet!