How thunderstorms, tornadoes and hurricanes form
Grade 9 Science Worksheet - Building Confidence
Circle the best answer.
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A lifted parcel and its surroundings (example data)
Height (km) Parcel (°C) Surroundings (°C) 0 30 30 1 20 19 2 10 8 3 0 -3 Ari lifts a parcel of air. Does it keep rising, and how does it compare at 3 km?
- No: air rises where it is cooler than its surroundings
- Yes: it stays warmer than its surroundings, by 3 °C at 3 km
- No: it cools 30 °C in 3 km, so it must sink back down
- Yes: it stays warmer, by 30 °C at 3 km, the surface temperature
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 160 m up
- About 125 m up
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?
- A, because the front forces warm, moist air upward
- D, because a cool ground lifts the air above it
- C, because sinking air over a desert lifts the air near 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 updraft cuts off the downdraft
- Minute 20, when updraft and downdraft both blow; the downdraft cuts off the updraft
- Minute 40, when just the downdraft is left; the updraft cuts off the downdraft
- Minute 5, when the updraft is just starting; the updraft cuts off the downdraft
A single cell lasts about 30 minutes (NOAA), yet a storm rains for 3 hours. Which explanation does Milo choose?
- Each cell lasts 3 hours when the air is warm enough
- The downdraft feeds the first cell's updraft, so that cell does not end
- Cool downdraft air triggers new cells nearby, so many cells follow each other
- One updraft keeps strengthening for the whole 3 hours
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?
- C, the multicell storm, because it lasts the longest of the other two
- 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
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 100 km out, where the winds are 50 mph
- About 50 km out, where the winds are 90 mph
- About 25 km from the center, where winds peak at 120 mph
- At the center, where the winds are 5 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 3, because 26.0 °C is close enough to 26.5 °C to count
- Day 1, because 28.0 °C is the warmest water on the path
- Day 2, because 26.0 °C is below the 26.5 °C it needs
- Day 3, because just 24.0 °C is cold enough to matter
Saffir-Simpson Hurricane Wind Scale (NHC)
Category Sustained winds (mph) 1 74 to 95 2 96 to 110 3 111 to 129 4 130 to 156 5 157 or higher A storm at 100 mph gains 30 mph. Which category does Esme name now?
- Category 4, since 130 mph begins that band
- Category 3, since a gain of 30 mph moves up one band
- Category 5, since a gain of 30 mph jumps to the top band
- Category 2, since a storm changes one band per day