How things work

Why do we see the flash from a gun before we hear noise?

Outer Space

What kind of atmosphere does Mars have?

Planet Earth

How do botanists know the exact age of a tree?

Living Creatures

Can any animal live for years without food?

Outer Space

Why do stars have different colors?

How things work

How does a combination lock work? Why is it considered more secure than the cylinder lock?

World

Why was it predicted that the world ends on December 21, 2012?

World

Which countries have been under foreign rule for more than a century?

How things work

How do sound waves travel through air? Why do they move faster in water than in air?

World

What are Polarized sunglasses? How do they work?

Living Creatures

Is Hummingbird the Smallest Bird? How Small is It?

Science and Technology

Why are dark things warmer than light colored or simply white things?

Science and Technology

Why a multistage rocket is needed to get a spacecraft off the Earth and into the space?

Outer Space

How will the Universe end? Or will it go on expanding forever?

How things work

Why an automobile's windscreen glass shatters into rounded pieces when it breaks?