Every four years something funny happens with our calendars -- we add a day! Why do we do this? Discover the science behind leap year.

What has two legs and carries its baby in a pouch? Fill in this crossword puzzle and learn some fun facts about two-legged creatures!

In 2012, an 80 million-year-old dinosaur was discovered, and you can learn all about this 20-foot, 2-ton horned herbivore.

Meet the red wolf, an endangered species of animal that was once very common, but in the past 50 year nearly became extinct!

Don't let school year learning slip away this summer: use this chemistry worksheet to practice identifying elements.

What do a key, a goldfish, and a tortoise shell have in common? Find out with this second-grade science worksheet!

Dive into the electrifying concept of electrical energy in this colorful worksheet!

Did you know that some caribou travel 3,000 miles in a year? This fun worksheet is jam-packed with fun facts about the caribou!

Did you know new species of animals are discovered every year? Color in this little cricket, the only one of his kind who can pollinate plants!

Describe how things feel when you touch them and push on them!

Practice classifying different animals in this engaging life science worksheet, created for second and third graders!

Hey, did you hear that? Explore real-life examples of sound energy with this kindergarten and first-grade worksheet!

Learn about the similarities and differences between objects in this colorful science worksheet!

Write down the name of each season that is shown in the pictures then color them and turn this worksheet into a unique placemat that can be used year-round!

If a ship went down, would these items sink or float? Your little one will decide, with this fun worksheet to help him hone sorting and categorizing skills.

Students practice classifying items as liquids or solids for a lesson on the states of matter in this fourth grade physical science worksheet.

See if you can identify the objects that let light pass through them with this kindergarten and first-grade worksheet!

These two children sure look alike -- maybe because they're twins!

Did you know that having a pouch or a shell can help an animal meet its needs? Learn how animals use different parts of their body with this matching worksheet for kindergarteners and first graders!

Who will win the marble race in this two-page physical science worksheet?

Use this cool 2-page worksheet to make your own big dipper clock!

Use this fossils worksheet to help a child learn about life on earth. Your child will learn about evolution and extinction, and also form a hypothesis.

Print out a set of weather-themed postcards to give your child practice identifying seasons. These weather postcards also allow kids to practice writing skills.

Match forms of energy to common examples in this third- and fourth-grade science worksheet!

Explore the strength of magnetic forces with this worksheet for third and fourth graders!

What does a seal eat? Kids choose the pictures that show what kind of food each animal likes to eat in this first grade life science worksheet.

Prepare for an exciting experiment with this cut-and-paste lab safety worksheet for first and second graders!

In this worksheet, children practice identifying animals of North America by their tracks.

Learn to identify and name the parts of a seed in this two-page science worksheet and quiz!