- Satellite
- Saturn
- Savant
- Schizophrenia
- Scientific Method
- Seasons
- Seed
- Set Theory
- Sexually Transmitted Diseases
- Skeletal System
- Slash-and-Burn Agriculture
- Sleep and Sleep Disorders
- Smell
- Snakes
- Soaps and Detergents
- Soil
- Solar System
- Solution
- Sonar
- South America
- Space
- Space Probe
- Space Station, International
- Spacecraft, Manned
- Spectroscopy
- Spectrum
- Speech
- Sponges
- Star
- Star Cluster
