How thunderstorms, tornadoes and hurricanes form
Grade 9 Science Worksheet - Building Confidence
Circle the best answer.
Read this first
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, by 30 °C at 3 km, the surface temperature
- No: it cools 30 °C in 3 km, so it must sink back down
- Yes: it stays warmer than its surroundings, by 3 °C at 3 km
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 160 m up
- About 3,500 m up
- About 125 m up
- About 1,000 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
- B, because cooling air in a valley rises out of it
- C, because sinking air over a desert lifts the air near it
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?
- One updraft keeps strengthening for the whole 3 hours
- Cool downdraft air triggers new cells nearby, so many cells follow each other
- 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
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?
- Wind shear of 20 m/s, which can roll air into a horizontal tube
- The Coriolis effect, which can spin a storm up from the ground
- 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?
- C, the multicell storm, because it lasts the longest of the other two
- A, the single cell, because any storm can spin
- B, the supercell, because its updraft rotates
- A, the single cell, because its updraft is the shortest
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 A, which has the warmest surface at 29 °C
- Area B, which is still 27 °C at 50 m
- Area C, which has the same temperature at both depths
- Area A, since 29 °C at the surface is above 26.5 °C
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 just 24.0 °C is cold enough to matter
- 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 26.0 °C is close enough to 26.5 °C to count
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 2, since a storm changes one band per day
- Category 4, since 130 mph begins that band
- Category 5, since a gain of 30 mph jumps to the top band
- Category 3, since a gain of 30 mph moves up one band
