Slide 1 / 53 Slide 2 / 53 3rd Grade Natural Hazards 2015-11-10 www.njctl.org Slide 3 / 53 Slide 4 / 53 Table of Contents Click on the topic to go to that section · Natural Hazards Lightning · Natural Hazards · Floods · Wildfires Works Cited · Return to Table of Contents Slide 5 / 53 Slide 6 / 53 Thunderstorms Supercells Supercells are incredibly large storms. Watch the video of a supercell Remember back to the weather unit. Under what conditions do by clicking in the box below. Use your observation skills as well as thunderstorms usually form? your knowledge to make a hypothesis about what is occurring in the storm. (Think about cloud formation and precipitation.) Thunderstorms often form during a cold front when cold air quickly approaches warm air. Click here to watch a video of the formation of a supercell. Source: Wikimedia Commons. Image by Smial. Source: Wikimedia Commons. Image by Lundeen.
Slide 7 / 53 Slide 8 / 53 Supercells Supercells Supercells can form when cold, dry air meets warm, humid air. Supercells are capable of creating incredibly high winds, hail and the Remember that warm air always rises above cold air. When the two strongest tornados. They create damage to homes and landscapes types of air masses collide, the cold air creates strong downdrafts and can injure animals and humans. while the warm air creates strong updrafts. Watch the beginning of the video again. Can you see air being pulled upwards? Think back about how supercells are formed. Is there any way that humans can prevent the formation of supercells? Source: Wikimedia Commons. Image by Kelvinsong. Source: Wikimedia Commons. Slide 9 / 53 Slide 10 / 53 Supercells Natural Hazards Supercells arise out of natural processes. There is no way that humans A supercell is a type of natural hazard. A natural hazard is an can prevent supercells from occurring. extreme event that occurs from natural processes. However, by studying them, we can come up with ideas that will Can you think of any other examples of natural hazards? Write your minimize the damage they do. examples below. Do you have any ideas about how we can prevent the damage of supercells? Write your ideas below. Slide 11 / 53 Slide 12 / 53 Natural Hazards 1 Natural hazards: There are many different types of natural hazards. In this unit, we will focus on lightning, floods and wildfires. A are caused by humans. B are completely unpredictable. C are caused by natural processes. D only occur where air masses collide. Source: Wikimedia Commons. Image by Averette. Source: Wikimedia Commons. Image by Smial. Source: Wikimedia Commons. Image by Farmartin.
Slide 13 / 53 Slide 14 / 53 2 Humans can eliminate natural hazards. True False Lightning Return to Table of Contents Slide 15 / 53 Slide 16 / 53 Making Lightning Activity Lightning Lightning is an electrical charge. During a storm, particles in the Investigate how lightning occurs in this activity. clouds are constantly rubbing together. This creates a charge. These charges are able to connect to other charges. When this happens, it creates a spark of electricity. We see this as lightning. Lightning can occur within the same cloud, between different clouds or from a cloud down to the ground. Source: Wikimedia Commons. Image by Fir0002. Source: Wikimedia Commons. Image by Griffinstorm. Source: Wikimedia Commons. Image by Clark. Cloud to cloud lightning Cloud to ground lightning Click here to view a map of where lightning is currently striking in the United States. Slide 17 / 53 Slide 18 / 53 Lightning Lightning Lightning is a serious natural hazard. Thousands of people are killed Suppose there is a thunderstorm outside your window. Where do you worldwide every year by lightning strikes. People who survive strikes think lightning will most likely strike: A, B or C? often have symptoms that last for the rest of their lives! Click in the red box to watch a video about lightning. As you watch, write down three interesting facts about lightning. Be ready to share your answers! Click here to watch a video about lightning. A Fact #1 Fact #2 Fact #3 C B
Slide 19 / 53 Slide 20 / 53 Dangers of Lightning Lightning Lightning occurs between different charges. It will happen in the Lightning is an unpredictable natural hazard and is dangerous for shortest distance possible. The lightning in this thunderstorm will hit many reasons. the tallest item on the ground. Can cause injury or death. · Can cause fires. · Can cause power surges that destroy electronic equipment. · A C B Source: Wikimedia Commons. Image by Bresson. Slide 21 / 53 Slide 22 / 53 Lightning Rods Lightning Rods Lightning is not something that can be prevented by humans. Click in each box to see how each component works. However, we can try to minimize the damage done by lightning. A lightning rod is composed of three parts: a metal rod, a wire and a Since the metal rod sticks up above ground rod. Look at the image below. Use your knowledge to predict the roof of the building, lightning will how a lightning rod can minimize damage from lightning. strike the rod instead of the building. The electricity from the lightning will travel down the wire instead of traveling through the building. The electricity will be dispersed underground by the ground rod. Source: Wikimedia Commons. Image by Wdchk. Source: Wikimedia Commons. Image by Wdchk. Slide 23 / 53 Slide 24 / 53 3 Lightning occurs between: 4 Will Iightning hit the shortest item on the ground? A positive charges. Yes B negative charges. No C positive and negative charges.
Slide 25 / 53 Slide 26 / 53 5 What do lightning rods do? 6 Lightning would hit a lightning rod instead of a house because lightning most often strikes the tallest structure and the rod extends higher than the house. A They conduct lightning into the ground instead of through a building. True B They reflect lightning back up into a storm. False C Create a warning system so that people know to evacuate. D They repel lightning away from a building. Slide 27 / 53 Slide 28 / 53 Flooding Whenever it rains, the ground soaks up the water that falls on it. Sometimes, water falls faster than the ground is able to absorb it. When this happens, water builds up and flooding occurs. Floods Return to Source: Wikimedia Commons. Image by Bidgee. Table of Contents Slide 29 / 53 Slide 30 / 53 Floods Flooding Floods can occur for many different reasons. How many can you Flood waters can be incredibly destructive. They can move bridges, think of? houses, trees and cars. In the United States, floods kill about 140 people a year and cause about $6 million in damage. After you brainstorm with a partner, click below to see some examples. Click here to see footage of rushing water due to heavy rainfall. Snow melt in the spring Excessive rainfall Source: Wikimedia Commons. Image by Dawg. Source: Wikimedia Commons. Image by Lefterov. A levee or dam breaks Excessive wind blows water onto land Source: Wikimedia Commons. Image by Averette. Source: Wikimedia Commons. Image by Oikos-team. Source: Wikimedia Commons. Image by Infrogmation.
Slide 31 / 53 Slide 32 / 53 Floods Levees Floods are a natural hazard. A levee is a structure, man-made or natural, that attempts to control flooding. Most levees are constructed to run beside rivers that are This means that humans ___________ stop them from happening but prone to flooding. we can _____________ the damage that they cause. (Write in correct terms to complete the statement.) How many different ways can you think of for humans to do this? Source: Wikimedia commons. Image by Gatley. Source: Wikimedia Commons. Image by Hathorn. Natural levee Man-made levee Levees have both positive and negative aspects. Can you think of one of each? Slide 33 / 53 Slide 34 / 53 Levees Fail Analyzing Levees Activity Unfortunately, levees can fail in several ways. Watch the video One method that humans use to minimize damage from floods is to below to see how this can happen. build levees. Analyze how levees work as well as their positive and negative aspects in this activity. Source: Water Education Foundation Click here to watch a video about different ways that levees can fail. Source: Wikimedia Commons. Image by Indolences. Slide 35 / 53 Slide 36 / 53 7 Flooding occurs when the ground soaks up water faster 8 Levees are indestructible. than it falls. True True False False
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