Social Science VSQ (2 Marks)

The quality of water is deterioting because we get it from polluted water sources. These water bodies are getting polluted due to dumping of untreated.

Ocean water is salty because it contains large amount of dissolved salts. Most of the salt is sodium chloride or the common table salt that we eat.

Factors affecting the height of the waves:

1. Speed off wind.
2. Duration of wind.
3. Distance the wind blows over water.

The process by which water continually changes its form and circulates between oceans, atmosphere and land is known as the water cycle.

Precipitation means any thing falling from the sky which include rain, snow, hail etc. on the surface of the earth when they become too heavy and unable to float in the air.

Earthquake cannot be predicted in advance but it is possible to give 3-4 hour notice of potential Tsunami. Such system are there in Pacific Ocean but not in Indian Ocean. Seismic activity and Tsunami threat is higher in the Pacific.

Cold and warm currents meet and create good fishing grounds around Japan and Eastern Coast of North America.

The gravitational pull depends upon mass and distance although Sun has more mass than Moon but the distance between Sun Earth much more as compared to the distance between Moon and earth thus the gravitational pull of moon is more compared to the Sun.

Dead Sea in Israel has salinity of 45 parts per thousand and there the water is dense making it easier for swimmers to float.

The continuous movement of ocean water is fascinating. The wet sand on beach, sea birds, the salty cool breeze, rhythmic movement of waves attracts one and all. On the other hand the water of ponds, lakes etc is calm.

Salinity is amount of salt in grams present in 1000gm of water. The average salinity of the ocean is 35 parts per thousand.

The factors are:

1. Winds.
2. Temperature.
3. Coriolis force.
4. Attraction of moon and sun depending upon its distances.

Tides are periodic rise and fall in the level of water in seas and ocean caused by the attraction of the moon and the sun. Twice a day, about every 12 hours and 26 minutes, the sea level rise and it falls.

Because it contains the large amount of dissolved salts. Most of the salt is sodium chloride.

Warm current- The Gulf Stream.
Cold current- The Labrador Ocean current.

On the occasion of World Water Day (22nd March) the need to conserve water is reinforced in different ways.

The rhythmic rise and fall of ocean water twice a day is called a tide. When water rises to its highest level and covers much of the ocean it is called high tide. During low tide the water falls to its lowest level and recedes from the shore.

It is because in place where warm and cold current meet. Tiny organisms called planktons are found in ambulance abundance which are an excellent source of food for fish, hence regions are rich fishing ground. Ex. Newfoundland coast where the Gulf stream and the Labrador current meet.

When the water on the surface of the ocean rises and falls alternatively they are called waves.

Quality of water is deteriorating because:

1. River water, which is our primary source of water, gets contaminated due to various reasons such as direct disposal of sewage by municipalities, excessive discharge of industrial pollutants, use for daily chores like washing, bathing, livestock bathing, garbage disposal, etc.
2. Water sourced from groundwater too has deteriorated due to the excessive use of pesticides & insecticides in agriculture, which seep into the groundwater as well as get washed away into the rivers.

• Rainfall, snow, rivers, ponds, springs and glaciers etc.
• Water from underground.

Most of the water percolates into the ground:

• The sun's heat evaporates the water as vapours. On cooling these vapours condenses and forms clouds
• Then this water may fall on land or sea as rain, snow or sleet.

• A terrarium is an artificial enclosure used for keeping small house plants.
• Our earth is like a terrarium.

Ocean currents are stream of water flowing constantly on the ocean surface in definite direction.

The warm ocean currents near the equator and brings about warm temperature over land surface. The cold currents carry water from polar latitudes and bring about foggy weather when it carries colder waters to warmer religions.