Tutor profile: Joji A.
Subject: Environmental Science
Many people are mistakenly interchange the word "contamination"and "pollution" . Actually what is the difference between the two?
Contamination is the presence of a substance that should not be present in the environment normally or its concentration may be higher in the environment. Pollution is when the contaminant causes harm to any organisms or infrastructure. Therefore we can have a contaminated environment without it being polluted but we cannot have a polluted environment without it being contaminated. For example, we measured the concentration of arsenic in the surface soils in two places A and B. The sampling locations A and B are close to a gold mine site and we measured the arsenic concentration in mg/kg unit. The average concentration of arsenic in the state is 3 mg/kg Metal location A Location B State average Arsenic (As) 7 87 3 Compared to the state average, at location A, the concentration is little higher, but may not cause harm as per the existing guidelines and at B the arsenic concentration is very high (87) and can cause harm to the organism. Therefore we can say that the surface soil at location A is contaminated and the surface soil at B is polluted.
Subject: Basic Math
A mall boy named Brian gone to a store and bought 2 bread packet worth 2.5$ each, 1 jar of milk worth 3$, 2 Kg of tomato (3.5 $ per kg) and 3 kg of sugar (1.2$ kg). He gave 20$ currency at the counter, but by mistake the counter staff gave 5$ as balance. When Brian reached home his Dad told him that the staff is mistaken and Brian got extra money and give back the extra money when he visit the store next time. So howmuch money Brian is supposed to give back to teh store
Total product cost item quantity unit price$ Total price$ Bread 2 2.5 5 Milk 1 3. 3 Tomato 2 3.5 7 Sugar 3 1.2 3.6 Grand Total 18.6 Cash given 20 Balance 1.4 (20 - 18.6) Balance received 5 Extra money given 3.6 (5 - 1.4) Simple we can work out in the following way Total Product cost = (2 x 2.5) + 3 + (2 x 3.5) + (3 x 1.2) = 5 + 3 + 7 + 3.6 = 18.6 Cash given = 20 Balance supposed to get = 20 - 18.6 = 1.4 Balance received = 5 Extra cash given = 5 - 1.4 = 3.6
Subject: Earth Science
What is hydrologic cycle?
The cyclic processes by which water circulates between the earth's oceans, atmosphere, and land, involving precipitation as rain and snow, drainage in streams and rivers, and return to the atmosphere by evaporation and transpiration is called Hydrologic cycle or Water cycle. The hydrologic cycle begins with the evaporation of water from the surface of the ocean and from other surface water bodies such as lakes and rivers. As moist air is lifted, it cools and water vapor condenses to form clouds. Moisture is transported around the globe until it returns to the surface as precipitation. Once the water reaches the ground three processes may occur; 1) Some of the water may evaporate back into the atmosphere called 'fly-off' . It may happen at the atmosphere as well. 2) Some water may penetrate the surface and become groundwater called 'cut-off' water Groundwater either seeps its way to into the oceans, rivers, and streams, or is released back into the atmosphere through transpiration. 3)The balance of water that remains on the earth's surface is 'runoff', which empties into lakes, rivers and streams and is carried back to the oceans, where the cycle begins again.
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