PDS AP Environmental Science 5th Period 2010-11

What is the difference between a primary succession and a secondary succession? I know that both of them have a huge effect on a community I am just not sure of what the difference is.

What is the difference between dynamic equilibrium and homeostasis because I know that they both are balanced out and stable.

I know the composition of the troposphere includes N2, O2, and the variable gases. Do we need to know what the stratosphere is made up of other than O3 (the ozone layer)? and if so can somebody tell me what else makes it up.

On Friday we continued our discussion on the Earth’s Atmosphere and why we have a diversity of climates throughout the Earth.

1.  UNEVEN HEATING OF THE EARTH

- Shape

- Tilt (23.5 degrees from the vertical axis)

- Orbit

We did a quick experiment with the globe to show how the shape and tilt affect the heating of the Earth. We used one of the globes at school and put thermometers on the Equator, North Pole, and between those two. We then had a bright light shine on the globe to see how the shape and tilt affects the thermometer’s temperatures. After time, the equator had risen 8 degrees, the one close to where we live had risen 6 degrees, and the thermometer further north had not changed. This showed that since the poles get less direct energy than the equator causing the Earth to be heated unevenly.

We also looked at how the Earth orbits around the sun:

http://www.learner.org/jnorth/tm/mclass/sl/1/4.html

There are parts of the world that have 1, 2, or 4 seasons due to where they are located and where the Earth is in comparison to the sun.

2. DIFFERENCES IN LAND AND WATER

- Distribution

- Specific Heat (The amount of energy it takes to change a piece of matter by 1 degree)

- Convection Cells

We did an experiment to look at how the distribution of the land and water can affect seasons. We compared water and soil under a strong a light with a thermometer. The water has a higher specific heat causing the water’s temperature to rise slower than the soil. Since there is more land north of the equator than south of the equator and the land heats up quicker than the Earth, it makes a difference on how the Earth heats up.

For an experiment to make a convection cell, we used two tubes (one with ice at the bottom and one with hot water). The equation D=M/V proves that warm air rises and cold air sinks. So we stuck a stick that had the edge on fire so that we could see the flow of the air with the smoke. We then put a tube connecting the hot and cold tube so we could see how the air flows between the two tubes. The cold air would sink, go through the connecting tube, and then rise in the warm tube creating a convection cell.

3. ROTATION OF EARTH

- Global Winds

- Coriolis Effect

http://theparadoxproject.com/Blog/tabid/68/EntryId/7/Four-Corners-of-the-Earth-Explained.aspx

We then looked at a diagram very similar to this one in our packet and discussed how the winds go both East and West. These winds take place in the upper troposphere and lower stratosphere, which are 2 of the structures that we talked about the day before.

We also watch a quick film on the Coriolis Effect, which showed why the winds go in the directions that they do. They showed a good example on a Merry-Go-Round with someone who was throwing a ball to another. YOUTUBE VIDEO. It is very similar to this video on Youtube. If someone on a merry-go-round throws a ball to someone off of it, it will appear as if the ball is curving, but if you watch it from above you will see that the ball is actually going in a straight line. It is because of the force that the Earth has as it is rotating and this is why the winds curve instead of going straight.

I believe that pollution is one of the biggest environmental issues. It affects our everyday lives by what we breathe. Not only does it affect us, but it also changes the environment that we live in. It can cause destruction to the coral reefs, acid rain, global warming (melting of ice glaciers and rise of sea levels). Pollution is a huge issue in our environment that needs to be controlled as best as possible.