Cyclones and Anticyclones: Pressure Systems Quiz

If the pressure is "high," then there is more weight pressing down on the ground. If air is pressing down, it must be sinking from higher up. Therefore, high pressure is always caused by sinking air.

If air sinks in a High, it must move away (outward) once it hits the ground. If the Earth is rotating, the Coriolis effect pulls that air to the right. Therefore, the result is a clockwise, outward spiral.

If air is at "low" pressure, it is rising. If air rises, it moves into thinner atmosphere and cools down. If air cools, it can no longer hold as much water vapor. Therefore, the water turns into clouds and rain.

If a weather system has a low-pressure center and spins inward, it is a cyclone. If a system has a high-pressure center and spins outward, it is an anticyclone. Therefore, calling a high-pressure system a cyclone is false.

If air is sinking in a High, it warms up as it reaches the surface. If air warms up, it "holds onto" its moisture instead of letting it turn into clouds. Therefore, Highs almost always bring clear, sunny weather.

If pressure is low in the center, air from the outside rushes "inward" to fill the empty space. If the Earth is spinning, the Coriolis effect turns that inward air to the right. Therefore, the air creates a counter-clockwise circle.

If a map shows an area of dense, cool air, it is labeled as High pressure. Meteorologists use "H" for High and the color blue to represent the cooler, heavier air.

If you measure the air and find one spot has less weight/force than the areas around it, then by definition, that spot is a Low Pressure system.

If air is "low" pressure, it is usually because it is warmer. If air is warmer, the molecules move faster and spread out. Therefore, the air becomes less dense and starts to rise.

If you have a "pile" of air (High) and a "hole" in the air (Low), the air will naturally fall into the hole. Therefore, wind always flows from High pressure toward Low pressure.

If a new weather system moves in, the weight of the air changes. If the weight changes, the needle on a barometer will move up or down. Therefore, the barometer is the tool used to track these systems.

If the Earth did not spin, wind would move in straight lines. If the Earth spins, the wind gets "pulled" to the side as it moves. Therefore, the Coriolis effect is what makes pressure systems spin in circles.

If the barometer "falls," it means the air weight is getting lighter. If the air is lighter, it is rising (a Low). If air rises, it creates clouds. Therefore, a falling reading predicts a storm.

If you are in the Southern Hemisphere, the Earth's rotation deflects wind to the left instead of the right. Therefore, the clockwise and counter-clockwise directions are swapped compared to the Northern Hemisphere.

If you want to see where a pressure system is on a map, you connect all the spots with the same pressure. Since "iso" means equal and "bar" means pressure, an isobar shows you these boundaries.

If isobars are close together, it means there is a huge pressure difference over a short distance. If there is a huge difference, air rushes much faster to fill the gap. Therefore, close lines mean high winds.

If a High (cold/dry) and a Low (warm/moist) meet, they don't mix easily. They push against each other. Therefore, the line where they fight is called a front.

If you are at sea level, you have the whole atmosphere above you. If you go up a mountain, some of that air is now below you. Therefore, there is less weight left to press down on you, making the pressure lower.

If "fair weather" means clear skies, it requires sinking air (High pressure). Since Low pressure systems involve rising air and cloud formation, they are the opposite of fair-weather systems.

If air rises, it expands because there is less pressure pushing on it. If a gas expands, it loses heat energy. Therefore, rising air in a Low system always cools down, which is how rain starts.