News and articles

Why is the sea salty?

Why is the sea salty?

Seawater is salty because it contains dissolved salts, primarily sodium chloride (common table salt). These salts enter the oceans and seas through natural processes...
20 February 2025
Why is the sea blue

Why is the sea blue

The sea appears blue because sunlight, when entering the water, refracts and scatters. The wavelength of blue light is shorter than that of red light, which means blue...
20 February 2025
Why is the sky blue

Why is the sky blue

The sky appears blue due to the scattering of sunlight in the Earth's atmosphere. As sunlight passes through the air, gas molecules scatter the light. Short-wavelength...
20 February 2025
Why Birds Migrate

Why Birds Migrate

Birds migrate because they need to find more favorable conditions for living and breeding. In autumn, they fly to warmer regions where food is easier to obtain, and in...
20 February 2025