Atmosphere Basic
This term describes the atmosphere at a specific time and place (daily or hourly changes).
weather
Large bodies of air with uniform temperature, moisture, and pressure are called what?
Air masses
This instrument measures temperature using alcohol or mercury inside a glass tube.
Thermometer
Wind moves from areas of ____ pressure to areas of ____ pressure. (Fill the blanks.)
high; low
A rotating funnel cloud that touches the ground is called a what?
Tornado
This term describes the usual weather over a long time in a region (the average).
Climate
What kind of front is the leading edge of colder air that is replacing warmer air?
Cold front
This instrument measures air pressure and indicates whether weather is likely to get drier or wetter.
Barometer
What global wind belt generally moves weather systems from west to east across the United States?
Prevailing Westerlies
What minimum sustained wind speed (in mph) classifies a storm as a hurricane? (Answer with the numeric threshold.)
74 mph74 mph (119 kph)
ame two factors included in a typical weather forecast. (Any two)
temperature, humidity, air pressure, cloud cover, precipitation, wind speed/direction (any two)
Which front is represented on weather maps by alternating triangles and semicircles and forms when a cold front catches up to a warm front?
Occluded front
What instrument measures the amount of rainfall at one location (often reported in mm or inches)?
Rain gauge
Explain why beaches are often windy during the day (describe sea breeze formation).
Sea breeze: land heats faster than water during day, warm air over land rises (low pressure) and cooler air over water sinks (high pressure), so air moves from sea to land.
Explain why Tornado Alley experiences frequent tornadoes (mention the air masses involved).
Because cool, dry polar air from Canada often meets warm, moist air from the Gulf of Mexico; the collision and rotation create conditions favorable for tornado formation.
Explain why cold air tends to sink while warm air tends to rise (use the term density).
Cold air is denser (more mass per volume) so it sinks; warm air is less dense so it expands and rises. Example explanation acceptable.
Explain what a stationary front is and how it appears on a weather map.
Stationary front: boundary where warm and cold air meet but neither moves; on maps shown as alternating blue triangles and red semicircles pointing in opposite directions.
Name and describe the tool that shows wind direction; include how it points relative to wind (what it points to).
Weathervane (wind vane); it points toward the direction the wind comes from (e.g., wind from the east makes the vane point east).
What are jet streams and how do they influence weather in North America, especially in winter?
Jet streams are fast-flowing, narrow air currents high in the atmosphere; the polar jet stream moves west to east across North America and can bring arctic air south in winter, strongly influencing weather systems.
List two differences between a tropical depression, a tropical storm, and a hurricane.
Tropical depression: weakest, organized low with low wind speeds; tropical storm: stronger organized storm with higher sustained winds and a name; hurricane: strongest, sustained winds ≥74 mph≥74 mph and a well-defined eye.
Describe how cloud cover affects daytime and nighttime temperatures (be specific about radiation).
Daytime: more cloud cover blocks incoming solar radiation so surface is cooler. Nighttime: clouds act like a blanket, trapping outgoing radiation and keeping surface warmer.
Describe the typical weather changes (temperature, humidity, and precipitation) that occur as a warm front passes through an area.
Warm front passing: air becomes warmer and more humid; broad area of cloudiness with gentle rain or light snow ahead; milder weather follows.
Describe how an anemometer works and what it measures.
An anemometer has cups on arms that spin in the wind; the rotation rate measures wind speed.
Describe how mountains can create a rain-shadow on the leeward side (include the words windward, leeward, rising, and descending).
Windward side: air rises as it hits mountain, cools and releases moisture (rain). Leeward side: air descends, warms, and dries, creating a rain-shadow (drier conditions).
Describe how an occluded front forms in a developing cyclone and why that can change weather in the region.
An occluded front forms when a faster-moving cold front catches up with a warm front, lifting warm air off the ground and creating a boundary between two cooler air masses; this often causes complex clouds and precipitation changes.