SCIENCE : CLASS VI
OPEN TEXT – BASED ASSESSMENT
SUMMATIVE EXAMINATION - II
THEMES
1. POLLUTION- A HAZARD TO MANKIND
2. GARBAGE MANAGEMENT – A CLEAN
SURROUNDING
OPEN TEXT MATERIAL
MARCH 2015
THEME 1: POLLUTION- A HAZARD TO MANKIND
AbstractHuman activities have put water and air in a bad state
Let’s save, freshen and conserve them before it is too late.
Clean air is vital for the existence of all living organisms on earth. Naturally existing mixture of
gases in the atmosphere, comprising of mainly Nitrogen, Oxygen, Carbon dioxide and water
vapours provides excellent conditions to support life. However, this natural composition of air is
getting disturbed due to variety of human activities.
The present text attempts to help the reader comprehend the situation, identify the causes and
effects of pollution and generate ideas as to what actions need to be taken to meet the emerging
challenges.
The Context
Pollution has been defined as the addition of any substance or form of energy to the environment
at a rate faster than the environment can accommodate. In simpler terms, pollution means the
poisoning of the environment by man.
Pollution has accompanied mankind ever since groups of people settled down in one place for a
long time. It was not a serious problem during primitive times when there was more than ample
space available for each individual or group. As the human population boomed, pollution became
a major problem and has remained as one ever since. Cities of ancient times were often unhealthy
places, fouled by human wastes and debris. Such unsanitary conditions favoured the outbreak of
diseases that killed or maimed many people living in those times.
The rapid advancement of technology and industrialization today is something that man can be
proud of. However, it has brought along with it many undesirable results, one of which is the
pollution of our environment. Humanity today is threatened by the dangers of air, water, land and
noise pollution.
The air that we breathe is heavily polluted with toxic gases, chemicals and dust. These consist of
the discharge from industrial factories and motor vehicles. Emission of carbon monoxide from
exhaust fumes is a major cause for concern too. Outdoor burning of trash and forest fires also
have contributed to air pollution. They cause coughing and respiratory problems. Owing to the
burning of fossil fuels, the level of carbon monoxide in the air is more than desirable. Too high a
level of carbon dioxide will cause the Earth's temperature to rise.
Water pollution has become widespread too. Toxic waste has found its way into our lakes,
streams, rivers and oceans. This waste is released by factories and sea-going vessels. Spillage of
oil by tankers and during the recent Gulf War has caused irreparable damage to marine life.
Thousands of sea animals have died or were poisoned by the pollutants in their natural habitat. As
such, it is dangerous for humans to consume sea food caught in polluted waters.
Dumping of used cars, cans, bottles, plastic items and all other kinds of waste material is an
eyesore. Much of the refuse is not biodegradable and this interferes with the natural breakdown
process of converting substances from a harmful form to a non-harmful one. As such, it becomes
a hazard to one's health.
We are often faced with noises from construction sites, jet planes and traffic jam. we may be
unaware of it but noise pollution has been attributed to causing a loss of hearing, mental
disturbances and poor performance at work.
To control environmental pollution, substances which are hazardous and can destroy life must not
be allowed to escape into the environment. This calls for united decision-making among world
leaders and a public awareness of the dangers of pollution.
1. What is Pollution and what are the causes of Air Pollution?
2. Write the measures to control Environmental Pollution?
(5 M)
(5 M)
MARKING SCHEME
QUE 1. Definition of pollution
1+4=5
`
Causes of Air pollution Toxic gases, chemicals and dust
 Discharge from industries and motor vehicles.
 Outdoor burning of trash and forest fire.
 Burning of fossil fuels
QUE 2. Names of substances that should not be released into the environment. 2+3=5
Measures to control the environment pollution.
2. THEME- GARBAGE MANAGEMENT – A CLEAN SURROUNDING.
Abstract Most of the things around you will be replaced or thrown away someday. Skates,
clothes, the toaster, furniture–they can break or wear out, or you may get tired of them.
Where will they go when they are thrown out? What kinds of waste will they create, and
how will it affect the environment?
The present text attempts to help the reader comprehend the situation of managing different
types of wastes and generate ideas as to what actions need to be taken to meet the emerging
challenges.
Context
What Happens to Things We Throw Away?
LANDFILLS
Most of our trash goes to places called landfills. A LANDFILL (or dump) is a low area of
land that is filled with garbage. Most modern landfills are lined with a layer of plastic or clay
to try to keep dangerous liquids from seeping into the soil and ground water supply.
THE PROBLEM WITH LANDFILLS
More than half of the states in this country are running out of places to dump their garbage.
Because of the unhealthful materials many contain, landfills do not make good neighbors,
and people don’t want to live near them. Many landfills are located in poor neighborhoods.
But where can cities dispose of their waste? How can hazardous waste–material that can
poison air, land, and water–be disposed of in a safe way?
INCINERATORS
One way to get rid of trash is to burn it. Trash is burned in a furnace-like device called an
incinerator. Because incinerators can get rid of almost all of the bulk of the trash, some
communities
would
rather
use
incinerators
than
landfills.
THE PROBLEM WITH INCINERATORS
Leftover ash and smoke from burning trash may contain harmful chemicals, called
pollutants, and make it hard for some people to breathe. They can harm plants, animals,
and people.
DID YOU KNOW?
The Fresh Kills landfill on Staten Island, New York, was the largest garbage dump in the
world. For years, people who live nearby complained about air and water pollution caused by
the massive pile of trash. They say that the fumes have made people sick. The dump closed in
April 2001. Now New York City’s garbage is trucked out of state.
REDUCE, REUSE,RECYCLE
You can help reduce waste by reusing containers, batteries, and paper. You can also recycle
newspaper, glass, and plastics to provide materials for making other products. At right are
some of the things you can do.
What Is Made from Recycle Materials?
• From RECYCLED PAPER we get newspapers, cereal boxes, wrapping paper, cardboard
containers, and insulation.
• From RECYCLED PLASTIC we get soda bottles, tables, benches, bicycle racks, cameras,
backpacks, carpeting, shoes, and clothes.
• From RECYCLED STEEL we get steel cans, cars, bicycles, nails, and refrigerators.
• From RECYCLED GLASS we get glass jars and tiles.
• From RECYCLED RUBBER we get bulletin boards, floor tiles, playground equipment, and
speed bumps.
To Reduce Waste To Recycle
Recycle newspapers, magazines, comic books, catalogs, cardboard, and junk mail.
Return soda bottles to the store. Recycle other plastics. Recycle glass bottles and jars.
Cut unwearable clothing into rags to use instead of paper towels. Recycle aluminum
cans and foil trays. Return wire hangers to the dry cleaners. Make a compost heap using
food scraps, leaves, grass clippings, and the like. Find out about your town’s rules for
recycling or disposing of batteries. Use both sides of the paper. Use cloth towels instead
of paper towels. Wash food containers and store leftovers in them. Reuse plastic bags.
Keep glass bottles and jars to store other things. Give clothes to younger relatives or
friends. Donate clothes to thrift shops. Keep leftovers in storage containers instead of
wrapping them in foil. Use glass or stainless steel pans instead of disposable pans. Cut
the amount of food you throw out. Try saving leftovers for snacks or meals later on. Use
rechargeable batteries for toys and games, radios, tape players, and flashlights
QUESTIONS
1. What are landfills? What are the problem with landfills ?
2. How can we reduce different wastes to be recycled ?
(5 M)
(5 M)
MARKING SCHEME
ANS 1. Definition of Landfill
1+4=5
Problems with Landfill (any two)
ANS 2. Names of substances to be reduced and recycled (any four)
Methods of recycling the wastes
2+3