TH
8
GRADE SCIENCE
STRAND 4
EARTH AND SPACE SCIENCE
ESS.8.8.1
VOCABULARY
• 1. GLOBAL WARMING – GLOBAL TEMPERATURES RISE DUE TO AN
INCREASED GREENHOUSE EFFECT.
• 2. GREENHOUSE EFFECT – NATURAL HEATING CAUSED BY ATMOSPHERIC
GASES TRAPPING HEAT AT EARTH’S SURFACE.
• 3. DEFORESTATION – THE REMOVAL OF FORESTS, MOSTLY TO CLEAR
LAND FOR FARMING, CONSTRUCTION, MINING, AND DRILLING FOR OIL.
• 4. REFORESTATION – THE PLANTING OF A LARGE NUMBER OF TREES.
• 5. ozone layer – layer in our atmosphere that protects living things by absorbing
harmful ultraviolet radiation from the sun.
vocabulary
• 6. Chlorofluorocarbons – a group of chemicals used as refrigerants and
aerosol spray propellants that destroy ozone molecules.
• 7. carbon dioxide (co2) – a gas consisting of carbon and oxygen which
vegetation helps to remove it from air.
• 8. ultraviolet radiation (uv rays) – harmful rays from the sun, which
cause sunburn, skin cancer, etc.
GLOBAL WARMING
• GLOBAL WARMING MEANS GLOBAL TEMPERATURES
ARE RISING.
• ONE REASON FOR GLOBAL WARMING IS THE INCREASE
OF GREENHOUSE GASES IN OUR ATMOSPHERE.
• THIS INCREASES THE “GREENHOUSE EFFECT”
• IN THE LAST 100 YEARS, THE MEAN TEMPERATURE ON
EARTH HAS INCREASED 1/2½ DEGREE CELSIUS.
GLOBAL WARMING
• JUST RECENTLY, SCIENTISTS HAVE REPORTED THAT
THE EARTH IS THE WARMEST IT HAS BEEN IN 400
YEARS.
• IF THE MEAN TEMPERATURE CONTINUES TO RISE, ICE
CAPS WILL MELT. LOW LYING AREAS MIGHT
EXPERIENCE INCREASED FLOODING.
• ALREADY SOME ICE CAPS ARE BEGINNING TO BREAK
APART, AND SEA LEVEL IS RISING IN SOME AREAS.
CLASSWORK
• Now, take out a sheet of paper. On it, tell me what effect global
warming will have on you.
• Be creative!
• You will have about 4 minutes.
GLOBAL WARMING
• HUMAN ACTIVITIES AFFECT THE AIR IN OUR ATMOSPHERE.
BURNING FOSSIL FUELS AND REMOVING VEGETATION AFFECT
THE ATMOSPHERE. BOTH ACTIVITIES ADD CARBON DIOXIDE
TO THE ATMOSPHERE AND CONTRIBUTE TO GLOBAL
WARMING.
• BY ANALYZING AIR BUBBLES TRAPPED IN GLACIERS,
SCIENTISTS HAVE DISCOVERED THAT IN ABOUT 1750, THERE
WERE 280 PARTS PER MILLION OF CARBON DIOXIDE IN THE
ATMOSPHERE. TODAY THERE ARE MORE THAN 350 PARTS PER
MILLION.
GLOBAL WARMING
• WHEN NATURAL GAS, PETROLEUM, AND COAL ARE
BURNED FOR ENERGY, THE CARBON IN THESE FOSSIL
FUELS IS COMBINED WITH OXYGEN. THIS INCREASES
THE AMOUNT OF CARBON DIOXIDE (CO2) IN THE
ATMOSPHERE.
• THE MASS REMOVAL OF TREES, CALLED
“DEFORESTATION” ALSO AFFECTS THE AMOUNT OF
CARBON DIOXIDE IN THE ATMOSPHERE.
GLOBAL WARMING
• FORESTS AROUND THE WORLD ARE BEING CLEARED
FOR MINING, ROADS, BUILDINGS, GRAZING CATTLE,
AND DRILLING FOR OIL.. FORESTS ARE ALSO DYING
FROM THE EFFECTS OF POLLUTION.
• AS TREES GROW, THEY TAKE IN CARBON DIOXIDE.
WHEN TREES ARE REMOVED, THE CARBON DIOXIDE
THEY COULD HAVE REMOVED FROM THE
ATMOSPHERE IS LEFT.
GLOBAL WARMING
• OUR WEATHER CAN ALSO BE AFFECTED BY GLOBAL
WARMING.
• HURRICANES WILL CONTINUE TO GET STRONGER. They
get their energy from the warm water they form in.
• If the water is getting warmer due to global warming, hurricanes
will have the extra energy to get bigger and stronger.
Global warming
• Weather on the inland could also be affected.
• Our severe weather is caused when hot air and cold air run into each
other.
• Cold air and warm air have different densities and do not mix, they battle
each other.
• Increasing the temperature of the air would increase the severity of the
storms.
Global warming
• Also adding warmth to the increasing global temperature is the
deterioration of our ozone layer.
• The ozone layer helps absorb harmful ultraviolet rays from the sun.
• Chlorofluorocarbons (cfc’s) that we use in air conditioners, refrigerators,
aerosol sprays, etc. break apart the ozone molecules in the ozone layer.
• A huge hole in our ozone layer continues to grow because of this.
review
• 1. these are in aerosol sprays, air conditioners, and refrigerators that break apart ozone
molecules……
• Chlorofluorocarbons
• 2. this is a gas in our atmosphere made up of carbon and oxygen……
• Carbon dioxide
• 3. this is the rising average temperature of the earth…
• Global warming
• 4. the sun’s rays come in, but have a hard time getting back out because of the
amount of carbon dioxide in the air….
• Greenhouse effect
review
• 5. what does vegetation do for our air?
• It uses the carbon dioxide in the air.
• 6. the mass cutting of our trees for commercial purposes……
• Deforestation
• 7. the harmful rays from the sun which cause sunburn and skin cancer…..
• Ultraviolet radiation.
• 8. The mass replanting of trees on our planet is called……
• Reforestation.