Sources and reference policy
For foundational concepts, this site favours public scientific agencies, standards bodies and research institutions over anonymous summaries.
NIST — measurement and SI
NIST SI units, the SI Learning Hub and NIST measurement publications support units, standards and measurement explanations.
NASA Science — light, stars and astronomy
NASA's electromagnetic-spectrum resources and Star Basics support optics and astronomy pages.
NOAA — weather and atmosphere
NOAA weather and atmosphere resources support cloud, pressure, humidity and weather-system explanations.
USGS — water science
USGS Water Science School supports water-cycle explanations.
U.S. Department of Energy — electricity and energy
DOE Electricity 101 supports basic electrical and energy-system explanations.
NIAID / NIH — immune-system basics
NIAID's immune-system overview and immune-response resources support the high-level immunity and vaccine page.
IUPAC — chemistry standards
IUPAC's periodic table resources support atomic and periodic-table terminology.
Editorial rule
Pages are rewritten in original plain language. A source trail is not used to imply that an agency reviewed or endorsed this site. When a topic is an active area of research, the article says so rather than presenting one study as settled fact.