How thunderstorms, tornadoes and hurricanes form
Grade 9 Science Worksheet - Building Confidence
Circle the best answer.
Cloud base is about 125 m high for each °C between the air temperature and the dew point. The air is 28 °C and the dew point is 20 °C. Where does Bo expect the cloud base?
- About 1,000 m up
- About 3,500 m up
- About 125 m up
- About 160 m up
Read this first
Table, Four settings (example), with columns Letter, Setting
A, a cold front pushes under warm, moist air; B, air cools and settles in a valley at night; C, high pressure sinks air over a dry desert; D, a calm, clear night cools the ground.
Kira looks for the setting that can lift air to start a thunderstorm. Which is it?
- C, because sinking air over a desert lifts the air near it
- A, because the front forces warm, moist air upward
- D, because a cool ground lifts the air above it
- B, because cooling air in a valley rises out of it
One storm cell's winds (example data)
Minute Updraft (m/s) Downdraft (m/s) 5 8 0 20 12 10 40 0 6 Jun reads the log. Which minute is the mature stage, and what ends the cell?
- Minute 20, when updraft and downdraft both blow; the downdraft cuts off the updraft
- Minute 5, when the updraft is just starting; the updraft cuts off the downdraft
- Minute 40, when just the downdraft is left; the updraft cuts off the downdraft
- Minute 20, when updraft and downdraft both blow; the updraft cuts off the downdraft
Air in a thunderstorm updraft rises 10 m/s. How long does Luz say a parcel takes to reach the cloud top at 12 km?
- About 20 minutes
- About 1,200 minutes
- About 200 minutes
- About 2 minutes
A single cell lasts about 30 minutes (NOAA), yet a storm rains for 3 hours. Which explanation does Milo choose?
- The downdraft feeds the first cell's updraft, so that cell does not end
- Each cell lasts 3 hours when the air is warm enough
- Cool downdraft air triggers new cells nearby, so many cells follow each other
- One updraft keeps strengthening for the whole 3 hours
Winds above one spot (example data)
Height (km) Wind speed (m/s) Direction 0 5 from the southwest 3 15 from the southwest 6 25 from the southwest Noah reads the winds. What do they show, and how big is it from 0 to 6 km?
- The Coriolis effect, which can spin a storm up from the ground
- Wind shear of 20 m/s, which can roll air into a horizontal tube
- Wind shear of 30 m/s, which can roll air into a horizontal tube
- No shear, since the wind keeps blowing from one direction
Three storms (example)
Storm Lasts Rotating updraft A 30 minutes no B 2 hours yes C 1 hour no Pia looks for the kind of storm that can make a significant tornado. Which storm is it?
- B, the supercell, because its updraft rotates
- A, the single cell, because any storm can spin
- A, the single cell, because its updraft is the shortest
- C, the multicell storm, because it lasts the longest of the other two
Winds across a hurricane (example data)
Distance from center (km) Wind (mph) 0 5 25 120 50 90 100 50 Ren reads the profile. Where is the eyewall, the ring of tall storms around the eye?
- About 25 km from the center, where winds peak at 120 mph
- About 50 km out, where the winds are 90 mph
- At the center, where the winds are 5 mph
- About 100 km out, where the winds are 50 mph
Three ocean areas (example data)
Area Surface (°C) At 50 m (°C) A 29 22 B 28 27 C 24 24 Tala needs water of 26.5 °C or warmer down to 50 m. Which area has enough heat?
- Area B, which is still 27 °C at 50 m
- Area A, since 29 °C at the surface is above 26.5 °C
- Area A, which has the warmest surface at 29 °C
- Area C, which has the same temperature at both depths
Water along one storm path at 50 m (example data)
Day Water at 50 m (°C) 1 28.0 2 26.0 3 24.0 A hurricane needs water of 26.5 °C or warmer to 50 m. On which day does Zee say the water first fails to fuel it?
- Day 2, because 26.0 °C is below the 26.5 °C it needs
- Day 1, because 28.0 °C is the warmest water on the path
- Day 3, because just 24.0 °C is cold enough to matter
- Day 3, because 26.0 °C is close enough to 26.5 °C to count