Helium

{
  "id": "MLC-T-MET-006220",
  "term": "Helium",
  "field": "Meteorology and atmospheric science",
  "definition": "A noble gas, the second lightest element, present in trace amounts in the Earth's atmosphere. Due to its low density, it is used to inflate weather balloons (radiosondes) that carry meteorological instruments aloft to collect atmospheric data. Its atmospheric concentration is approximately 5.2 parts per million by volume.",
  "url": "https://mlchart.com/terminology/meteorology/helium/"
}