07:28

Why are the Olympic Games so popular?

06:58

How do cicadas make so much noise?

05:55

How high can birds fly?

07:28

Does trash last forever?

03:35

How dangerous is it to look at the Sun?

07:37

Why does it get dark during a solar eclipse?

07:04

How many kinds of cacti are there?

07:11

Why are four-leaf clovers so rare?

07:31

Why do we have daylight saving time?

06:07

What's the smallest animal on Earth?

07:22

How does mail get delivered?

07:31

Do astronauts ever feel motion sick in space?

05:51

Why can we see our breath in the cold?

06:45

Is the five-second rule true?

06:55

Could you build a real house out of cookies and candy?

06:59

What was the Ice Age like?

06:06

How do you know if you need glasses?

06:17

How do erasers erase?

05:58

How do polar bears walk on ice and snow?

07:50

What's the most dangerous animal in the ocean?

06:38

Do wild animals ever dress up in costumes?

07:16

Who invented the high five?

07:05

Does any place not have fall?

07:44

Are dolphins really one of the smartest animals in the world?

06:59

Is a tomato a fruit or a vegetable?

07:22

What's the hottest place on Earth?

07:49

How does composting work?

05:56

How were skateboards invented?

06:45

What is dust?

07:54

Why does it matter if an animal is endangered?

07:13

Why do animals become endangered?

06:58

How do we know if an animal is an endangered species?

06:15

How do optical illusions trick us?

08:50

How do astronauts get ready for space?

05:39

Do dogs sweat?

06:41

Can any animal outrun a cheetah?

06:10

How do you fix a broken heart?

06:23

Why do fireflies glow?

06:18

Why are some people left-handed?

06:46

Who invented ice skates?

06:48

How do braces work?

06:32

Could a kid win a race against a penguin?

07:17

Why do flies just appear in the trash?

06:48

Can trees talk to each other?

07:32

What's the longest anyone's ever stayed awake?

06:28

What's the biggest shark that ever lived?

06:25

How do they make imaginary movie characters look so real?

05:50

Why do we get head lice?

07:47

How do some people get so good at sports?

08:45

Why do whales sing?

07:15

How is ice cream made?

06:59

Do any plants eat animals?

07:08

Who invented school?

07:23

What does a scientist do?

07:08

How do you build a bridge that lasts for 100 years?

05:49

Can animals be friends with other kinds of animals?

07:33

Are killer whales really dangerous?

08:58

Why are coral reefs so colorful?

07:40

How were bicycles invented?

08:20

How do scientists learn about wild animals?