The Atmosphere

12345678
Across
  1. 4. the pressure exerted by the mass of the atmosphere.
  2. 5. a colorless unstable toxic gas; it differs from normal oxygen (O2) in having three atoms in its molecule (O3); it helps absorb many of the harmful rays from the sun.
  3. 6. the fifth layer of our atmosphere; marks the boundary to outer space.
  4. 7. the fourth layer of the atmosphere; known for its extremely high temperatures and the northern lights.
  5. 8. the middle layer that extends about 85 km above the surface of the earth; coldest layer.
Down
  1. 1. the second layer of atmosphere extending up to about 50 km above the earth’s surface; the ozone layer is found here.
  2. 2. the first layer of the atmosphere, about 10km high; it gets colder with an increase in altitude; most cloud formations and weather occur here.
  3. 3. the envelope of gasses surrounding the earth; it is mostly composed of 78% nitrogen, 21% oxygen.