1. Weather

2. Water Cycle You will be given a sheet.
You will be given part of the water cycle.
You are to draw color a symbol that represents your part.
When your group is complete you will tape to the back wall where it would be placed in the water cycle.
(Original source of energy for the water cycle, transpiration, run-off, condensation, evaporation, precipitation, ground water, gravity)
You have 15 min

3. Density
Density
Because all objects are made out of molecules it is possible to determine how tightly packed those molecules are. This is known as density. The more tightly packed the molecules of an object, liquid or gas are, the more dense we say they are.

4. Density
The density of a solid object will remain the same no matter where we place the object. The density of a liquid will change only slightly. However, the density of a gas changes drastically.
A gas will expand to fill whatever space it is provided.
If we take a certain amount of gas out of one container, and place it into another container that is twice as large, the gas will expand filling the larger container.
We still have the same number of gas molecules, but now, they are filling a much larger area. So, the gas is half as dense as it was
in other words, there is twice as much space between the molecules as there was in the smaller container.

5. Density
Density is a measure of how much mass is contained in a given unit volume
(density = mass/volume
Put simply, if mass is a measure of how much ‘stuff’ there is in an object, density is a measure of how tightly that ‘stuff’ is packed together.

6. Density Problems
Work on sheet at your table

7. Pressure

8. High Pressure Atmospheric Pressure
force exerted by the weight of the air
Atmospheric pressure is defined as the force per unit area exerted against a surface by the weight of the air above that surface. In the diagram, the pressure at point "X" increases as the weight of the air above it increases.
Thinking in terms of air molecules, if the number of air molecules above a surface increases, there are more molecules to exert a force on that surface and consequently, the pressure increases.
Atmospheric pressure is measured with an instrument called a "barometer", which is why atmospheric pressure is also referred to as barometric pressure.

9. High Pressure Anticyclones bringing fairer weather
There are several key surface features to consider when making a forecast.
We will begin with the anticyclone, which is a high pressure center where the pressure has been measured to be the highest relative to its surroundings. That means, moving any direction away from the "High" will result in a decrease in pressure. High pressure centers often represent the centers of anticyclones.

10. A high pressure center is represented on a weather map by a blue "H" and air diverges outward from a surface high. With air moving away from this region, air must sink from above to replace it. This sinking motion leads to generally fair skies and no precipitation near the high.

11. High Pressure
Winds flow clockwise around a high pressure center in the northern hemisphere (above). Temperatures are dependent upon the location relative to the high. Northerly winds associated with an approaching high are likely to result in colder temperatures while southerly winds found on the backside of a high, or once a high has passed through, typically result in a warming trend.

12. Effects of Cloud cover Effects of Cloud Cover
on forecasted temperatures
During the day, the earth is heated by the sun. If skies are clear, more heat reaches the earth's surface (as in the diagram below). This leads to warmer temperatures

13. Effects of Cloud Cover
However, if skies are cloudy, some of the sun's rays are reflected off the cloud droplets back into space. Therefore, less of the sun's energy is able to reach the earth's surface, which causes the earth to heat up more slowly. This leads to cooler temperatures.

14. Effects of Cloud Cover
At night cloud cover has the opposite effect. If skies are clear, heat emitted from the earth's surface freely escapes into space, resulting in colder temperatures.

15. Effects of Cloud Cover
However, if clouds are present, some of the heat emitted from the earth's surface is trapped by the clouds and reemitted back towards the earth. As a result, temperatures decrease more slowly than if the skies were clear

16. Fronts

17. Cold Fronts
Forecast Tip: If there is sufficient moisture in the air and a forcing mechanism like a cold front (for example) is approaching the area, then there is an increased probability that precipitation will occur.
Clouds and precipitation are formed by the upward motion of air. Therefore, there must be a mechanism present to lift the air. Fronts often serve as such a mechanism. Air on one side of the front typically blows in a different direction from the wind on the other side, causing the air to converge, or pile up right along the frontal surface.