natural disasters n.
Skip this Video
Loading SlideShow in 5 Seconds..
Natural Disasters PowerPoint Presentation
Download Presentation
Natural Disasters

Natural Disasters

150 Vues Download Presentation
Télécharger la présentation

Natural Disasters

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Natural Disasters Sink Holes, Floods, Fires, and Droughts

  2. Natural Event/Disaster effects on the Environment • Natural events and disasters have both beneficial and adverse effects to an environment.

  3. History of Fire • Since the beginning of time man has depended on fire for survival. • Fires have been used to heat homes, cook foods, disinfect instruments, and generate power. • A fire occurs as the result of a chemical reaction (when two chemicals interact causing an explosion at the atomic level) they grow with the addition of oxygen.

  4. Fires • Fires can be caused by lightning, volcanic eruptions, droughts, hot weather, and humans • Fires can spread quickly with fuel from dead branches, dry leaves, and rotting plants. During periods with little rain, a fire can spread even faster Fires: • ground fires – burns grass and low lying vegetation • surface fires – burns trunks of trees as well as low lying vegetation • crown fires – burn through the top of trees • brush fires – caused by people either on purpose or accidently

  5. Fires PROS • Some plants require fire to release their seeds --ex. scrub pines & pitcher plants • keeps ecosystem in balance by clearing away dead and dying plants to make more room for new plants to grow CONS • damage natural resources • destroy wildlife habitat • destroy homes and businesses • can lead into increased soil erosion

  6. How to put fires out • Because fires are a result of a chemical reaction there are several different ways to put out a fire • Water (not effective on grease, chemical or electrical fires) • Fire extinguisher • Fire blanket • Stop, drop, and roll • Sand • Something VERY important to keep in mind is that fire’s need oxygen to survive so the LAST thing you want to do is blow out a fire or put it in front of a fan, you may make it bigger or spread it!

  7. Drought • can be classified as a long period of time with little to no precipitation • can cause serious problems such as crop damage, livestock death, & water supply shortages. • severity of a drought depends upon the degree of moisture deficiency, the duration, and the size of the affected area • can increase risk of fire

  8. Droughts • without sufficient amounts of water, governments often enact water restrictions • Florida can measure the degree of drought by the levels of water in Lake Okeechobee *Remember* -water makes up about 75% of the Earth’s surface -water makes up about 70% of our own body

  9. The great dustbowl of the1930’s During the 1930’s the western part of the United States suffered the greatest drought in the countries history. 70% of the land completely dried out and began to fly away like dust

  10. Floods • Can be caused by heavy rains, river overflow, ocean waves, snow melts too fast, or dam or levee break. • Flooding may be only a few inches or it may cover a multistory house. • Floods that happen very quickly are called flashfloods.

  11. PROS • seasonal flooding can renew important nutrients • floods can recharge water supplies in dams and underground aquifers. • can distribute large amounts of water and suspended river sediment over vast areas. CONS • can destroy homes and endanger lives

  12. Sink Holes • Sinkholes are common where the rock below the land surface is limestone, carbonate rock, salt beds, or rocks that can naturally be dissolved by groundwater circulating through them. As the rock dissolves, spaces and caverns develop underground. Sinkholes are dramatic because the land usually stays intact for a while until the underground spaces just get too big.

  13. Invasive Species • These are plants, animals, or pathogens that are non-native (alien) to the ecosystem that when present, causes a disruption to the ecosystem by displacing native species, killing native species, or competing with other native species for resources. These can be introduced by storms, floods, or even via human interactions.

  14. Disease • Disease is a normal part of the natural world. Most ecosystems have organisms like viruses, bacteria, fungi, and parasites that cause disease. The native wildlife may not have natural immunity to them, which can potentially cause a population to die out or go extinct. Disease can be spread through air, water, or direct contact.

  15. Review • Fire is a result of _______________ • Fire needs _________ to survive • This type of fire happens when you rub two things quickly together • You should use ____ to put out an open flame fire

  16. Review • A period of extremely dry weather ____ • Droughts put ____ in the atmosphere • Droughts can kill (list 3) • Droughts are caused by__________ • Droughts also cause water levels to __ • What is the lake that provides us with water?

  17. Review • Excessive rain or severe weather can cause ____ • Floods can be good and bad, why? • _________ are floods that happen quickly