Fact Check: "The Earth's atmosphere is composed of 78% nitrogen."
What We Know
The claim that the Earth's atmosphere is composed of 78% nitrogen is supported by multiple credible sources. According to NASA, the dry air in Earth's atmosphere is approximately 78.08% nitrogen, along with 20.95% oxygen and 0.93% argon (NASA). Similarly, the National Oceanic and Atmospheric Administration (NOAA) confirms that nitrogen is the most abundant gas in the atmosphere, comprising about 78% of its dry composition (NOAA). Other educational sources, including the UCAR Center for Science Education, also state that nitrogen constitutes about 78% of the air we breathe (UCAR). Furthermore, Wikipedia corroborates this information, noting that dry air contains 78.08% nitrogen by mole fraction (Wikipedia).
Analysis
The claim is well-supported by scientific data and reputable institutions. The percentages provided by NASA and NOAA are derived from extensive atmospheric studies and measurements, which are generally accepted in the scientific community. The consistency across various sources, including educational institutions and encyclopedic references, adds to the reliability of the information.
However, it is important to note that the 78% figure refers to the dry composition of the atmosphere. The presence of water vapor can vary, sometimes constituting up to 4% of the atmosphere, which can affect the overall composition but does not change the nitrogen percentage in dry air (NOAA).
The sources cited are credible, as they come from established scientific organizations and educational institutions. NASA and NOAA are both recognized for their rigorous scientific standards and contributions to atmospheric science, while UCAR is a respected educational organization focused on atmospheric research.
Conclusion
Verdict: True. The Earth's atmosphere is indeed composed of approximately 78% nitrogen. This figure is consistently supported by multiple authoritative sources, confirming its accuracy.
