4th grade-ch. 7 lesson 1 what are hurricanes

Ch. 7Lesson 1What are

hurricanes?

Brainstorm things that can happen during and after a hurricane.

DURING:• Strong winds• Windows break• Electricity turns off• People eating pickles-nonperishable food• High voltage lightning

AFTER:• Cutting down damaged trees• Flooding • Fixing roofs• Buzzing saws• Fixing houses

Hurricane Wilma

hurricanedangerous low pressure storm

bands of thunderstormsenergy from warm ocean water

lose strength over land

Stages of hurricanes

What happens Wind speed

1. Tropical depression

Low pressure-warm ocean water-form

thunderstorms-air swirls

Up to 61 kmh

2. Tropical storm

Air pressure drops

Over 62 km/h

3. Hurricane Thunderstorms spin

At least 119 km/h

882 mb

Cat-2 hurricane

air swirls

eye of the hurricane

• in middle of hurricane

• gentle winds

• no rain

• few clouds

effects of winds & water

• winds- break tree trunks, lift roofs, flatten buildings

• water- heavy rain, storm surge

storm surge• rise in sea level caused by hurricane’s winds

• causes flooding

Ways hurricanes can be helpful:

•Rain gives plants water

•Prevent wildfires

•Remove non-native plants

how scientists predict hurricanes:

• Use computer models & satellites to track hurricane’s path

• Predict strength, direction & speed

Make a Model of Storm Surge!• What You'll Need:• A plastic plate, play-dough, 6 sugar cubes, One cup of water tinted with blue food coloring • Hair dryer, A baking sheet or plastic garbage bag

• Make it Happen!• In this activity, you will make a model coastline and decide where houses are placed along it.

Then you will test your model to see if where a coastline like that would flood during storm surge.

• Using play dough, create a coastlines against one side of the plastic plate. Decide where you'd like to place the sugar cube houses along the coast.

• Fill the plastic plate with blue water. This water represents the ocean.Test your models by aiming the hair dryer so that wind blows across the ocean towards the land. The water will have nowhere to go and will pile up on the shore. (Put your model in a baking pan or on plastic garbage bag to prevent spilling water.)

• Did you see water pile up along the coast? Were any of your sugar cube houses flooded? Change the shape of the coastline to see how it affects storm surge. Change the location of the houses to see if there is anywhere where they will not flood.

• How Does it Work?• In this model, the blowing hair dryer is like the winds of a hurricane. Hurricane winds push

water into a mound at the storm’s center. As the hurricane gets closer to the coast, the mound of water is unable to escape anywhere but onto land. A hurricane will cause more storm surge in areas where the ocean floor and coastal areas slope gradually.

Jobs • 1 & 2 - Make coastline from clay

• 3 & 4 – Place “houses” on coastline

• 5 – Pour “warm ocean water”

• 6 – “Hurricane winds”