One.

SUMMARY OF TODAY'S LESSON:
There are four interdependent parts called "spheres":
- lithosphere (rigid outermost shell of the planet)
- hydrosphere (all the planet's solid, liquid & gaseous water)
- biosphere (all the planet's living organisms)
- atmosphere ( all the planet's air)

Atmosphere
Nitrogen + Oxygen = 99% of the dry atmosphere

Environmental Lapse Rate = decrease in temp with increase in altitude through the troposphere.
Ozone Layer found in stratosphere; shields Earth's life from harmful effects of the Sun's UV Rays. However, CFCs which are released into the atmosphere are broken down by the Sun into chlorine which then attacks the ozone layer. Luckily, the Montreal Protocol has been successful.
As pressure decreases, temp in
troposphere - decrease
stratosphere - increase
mesosphere - decrease (lowest)
thermosphere - increase

Carbon Cycle
- a biogeo cycle where carbon is exchanged among the spheres. (very impt)
- Global Carbon Budget: balance of the exchanges of carbon in the carbon cycle
- sink/source
- carbon sinks: 'natural/manmade reservoir that accumulates and stores some carbon- containing chemical compound for an indefinite period.'
- Process of carbon sinks removing CO2 from atmosphere: carbon sequestration

I think the way and the fact that the 4 spheres interact with one another is very interesting, how everything can connect to each other, and affect them; the chain reactions. The spheres also remind me of AVATAR: the last airbender show, where the 4 powers are air, water, earth and fire I think.. The way everyone groups our world are more or less the same, just like the 4 spheres - earth, water, air, and us!
Then came the other 4 'spheres' - troposphere, stratosphere, mesosphere, thermosphere. It's a wonder whether they grouped this according to the increase/decrease of the temperature as the pressure decreases, since they're alternating.

I wish to learn more about how they all connect with one another, it makes nature feel interesting.

HOMEWORK: Read up on Nitrogen Cycle

- Lifang(: