Tempo is the speed of a song. It tells musicians how fast they should play. We measure tempo using b
[798호]
The golden ratio can be found everywhere in nature. Picture a Nautilus shell ? its spiral also fol
[797호]
A compass is a tool that shows directions. Inside a compass, a small, magnetized needle aligns with
[796호]
Photographic film is a strip of light-sensitive material that captures images. It contains tiny silv
[795호]
Think of your immune system as your personal bodyguard, always alert for trouble. It immediately res
[794호]
Fossils are the remains or impressions of things that lived long ago. An animal or plant must be bur
[793호]
Evolution is a process where living things change over time to survive in their environment. For exa
[792호]
Human rights are things that everyone has a claim to, no matter who they are or where they live. For
[791호]
Color is a perception of the wavelengths of light that bounce off an object and reach our eye. Objec
[790호]
Gravity is an invisible force that pulls objects toward each other. It keeps us on the ground and pl
[789호]
1 2 3 4 5 6 7 8 9 10 [다음10개]
