> 기획/특집
[영문기고] Scientists discover air is heavier than we thought
i가스저널  |  webmaster@igasnet.com
폰트키우기 폰트줄이기 프린트하기 메일보내기 신고하기
승인 2005.01.26  
트위터 페이스북 미투데이 네이버 구글 msn
Scientists have discovered that the air in the atmosphere around us is heavier (more dense) than they had previously thought. Knowing this will enable scientists to measure the mass of objects more accurately than ever before.

Writing in the Institute of Physics journal Metrologia, a team from the Korea Research Institute of Standards and Science (KRISS) and the International Bureau of Weights and Measures (BIPM) in France, report a new determination of the content of argon in air, the first since 1969.

If asked to name the major chemical components of air, most of us would list oxygen (about 21%), carbon dioxide (about 0.04%) and water vapour (typically about 1%). The principal component of air is nitrogen and the only other major component is argon (about 0.9 %).

Argon is chemically inert and its presence in the atmosphere poses no problem to human well-being. Old measurements dating from as early as 1903 gave the content (moles of argon/mole of dry air) as 0.934 %. The most recent value available until now was lower (0.917 %) and was thought to supersede the previous result.

The work reported in Metrologia gives a new figure (0.9332  0.0006)%, very close to the measurement results of 100 years ago. The uncertainty in the new measurement is given at the 95% confidence limit and is of unprecedented accuracy.

The analysis was performed at KRISS using high precision mass spectrometry. A set of air-like calibration gas mixtures was prepared by very careful weighing of pure gases into high pressure cylinders. Analysis of these synthetic air mixtures along with samples of natural air contained in other high pressure cylinders yielded the result reported in Metrologia.

Argon content is important to a small community of scientists working on precision mass measurements. To understand why, think of the old puzzle: which weighs more, a kilogram of feathers or a kilogram of lead? If it were possible to do the weighing on a very precise balance, we would see that the balance readings are identical for the feathers and the lead if the weighing is carried out in a vacuum. But the feathers would produce a considerably lower balance reading for measurements in air. This is because feathers are more buoyant in air than is lead (Archimedes’ Principle).

Mass metrologists use an equation to correct for the effect of air buoyancy. The equation includes the air density which, in turn, includes a parameter for the content of argon in the atmosphere. The different historical values for argon content lead to a difference in air density of just under 0.01%, or about 15 micrograms in the apparent mass of one kilogram made of stainless steel (15 parts in 109). The higher the argon content, the denser the air.

Even though the density of air is roughly 800 times smaller than water density, the effects of air buoyancy are easily seen in precise weighing. Thus the air density calculated from the new value of argon content should agree with precise data obtained from the feathers and lead experiment.

There is a stainless-steel cylinder on one side, which is hollow inside, representing the low-density feathers. On the other, a thick-walled tube is a solid piece of stainless steel, thereby representing the high-density lead. The cylinder and tube have the same surface area, which simplifies analysis of the experimental data. The results of measurements with several different sets of hollow and solid objects are reported in a companion article in Metrologia, written by scientists at the BIPM and the Physikalisch-Technische Bundesanstalt, in Germany.

Michael Esler, from the Chemistry Section at BIPM, and one of the authors, said: “The results confirm the new argon content and can explain discrepancies that had already been observed using the previously-accepted value dating from the mid-20th century. The new determination of argon content was motivated by numerous mass measurements which stubbornly failed to agree with the accepted formula for air density. The new results should lead to improved coherence among high precision mass measurements”.

(최근 Institute of Physics誌(영국 런던)에 실린 한국표준과학연구원 김진석 박사 관련 기사원문)
i가스저널의 다른기사 보기  
폰트키우기 폰트줄이기 프린트하기 메일보내기 신고하기
트위터 페이스북 미투데이 네이버 구글 msn 뒤로가기 위로가기
이 기사에 대한 댓글 이야기 (0)
자동등록방지용 코드를 입력하세요!   
확인
- 200자까지 쓰실 수 있습니다. (현재 0 byte / 최대 400byte)
- 욕설등 인신공격성 글은 삭제 합니다. [운영원칙]
이 기사에 대한 댓글 이야기 (0)
가장 많이 본 뉴스
1
[기획] 2024년(甲辰年) 산업용 및 특수가스 관련업종의 현황분석
2
[COMPANY NEWS] 유니온가스, 국제공인시험기관 KOLAS 인정 획득
3
[Click] 이차전지 전주기 산업경쟁력 강화 나선다
4
[Click] 액화수소 상용화시대, 규제샌드박스로 준비
5
[COMPANY NEWS] 케이앤디에너젠, 울산에 92,000N㎥/h 수소생산공장 건설
6
가스안전公 노오선 기술이사, SK에너지(주)CLX·린데수소에너지(주) 현장점검
7
가스안전公 박경국 사장, 남서울 LPG충전소 현장 점검
8
[Issue] 연구실 안전 위한 ‘고압가스 안전관리 매뉴얼’ 발간
9
[Click] 청정수소 시장 선점위한 국내 과제는?
10
[COMPANY VIEW] 에어프로덕츠, 평택 포승지구에 청정 그린수소 생산시설 건립
회사소개기사제보광고문의불편신고개인정보취급방침이메일무단수집거부청소년보호정책
회사 : i가스저널 | 제호 : 온라인가스저널 | 등록번호 : 서울, 아53038 | 등록일자 : 2020년 5월 7일 | 발행인 : 이락순 | 편집인 : 김호준
주소 : 서울시 강서구 마곡중앙4로 18 마곡그랑트윈타워 B동 702호| 전화번호 : 02-2645-9701 | 발행일 : 2020년 5월 7일 | 청소년보호책임자 : 이락순
Copyright © 2004 아이가스저널. All rights reserved.