Tuesday 19 March 2013

Other Effects of Air Pollution

Besides acid rain, air pollution can have some other undesirable side effects.

*Carbon Monoxide Emissions: Incomplete combustion of fossil fuels releases carbon monoxide, which is hazardous to humans as it attachs easily to red blood cells compared to oxygen and reduces the amount of oxygen that can be carried in the bloodstream, reducing the rate of respiration and potentially leading to death.

*Greenhouse gases: Releasing greenhouse gases into the atmosphere contributes to global warming.

Test for Negative Effect on Statues and Buildings

Method

1. In this experiment, we will substitute dilute hydrochloric acid for acid rain and calcium carbonate (limestone) chips for composition of the statues. All the calcium carbonate chips must be from the same source and must have the same weight- 2 grams. First, I will add the dilute hydrochloric acid to the calcium carbonate chips. We will weigh each chip before the experiment to ensure they have the same mass. Each sample will receive 30ml of solution, however the concentration of acid in each solution will vary. With each sample, we will increase the amount of water in the solution by 5ml while decreasing the volume of distilled water by 5ml. So for example, the first sample will receive 25ml of hydrochloric acid and 5 ml of distilled water, the second sample will receive 20ml of hydrochloric acid and 10ml of distilled water, etc. One sample should have a neutral pH, containing 0ml of hydrochloric acid and 30 ml of distilled water.

2. After preparing the samples, we will leave them in test tubes in the same location at room temperature (28 °C) for a week. The samples should be sealed to prevent other chemicals from entering and affecting the pHs of the samples.

3. After a week, we will weigh each chip again and record each sample's change in mass. We will then repeat the experiment three times to ensure reliability.

Prediction
The chip that was placed in the solution with the highest concentration of acid should lose the most mass. The chips placed in solutions with lower concentrations of acid should lose less mass, and the chip placed in the neutral solution should have lost no mass. From this we can conclude that dilute acid such as acid rain can corrode limestone statues and buildings, whereas pure distilled water does not.

Equipment
*Electronic Balance
*Test Tubes
*Test Tube Rack
*Limestone/Marble Chips
*Measuring Cylinders

Safety
*Wear goggles while handling acid to prevent acid from splashing into eyes.
*Long hair should be tied back.
*Skin contact with acid should be avoided; caution should taken when handling acid.

CORMS

C (Change): The concentration of acid in each sample.
O (Organism): N/A
R(Repeat): Repeat 3 times to ensure reliability
M (Measure): The change in mass of each sample after a week.
S (Same): Each sample should have the same mass and receive the same volume of solution. All samples should be kept at the same location and at the same temperature, room temperature (28°C).

*Hydrochloric acid can be substituted for sulphuric acid in this experiment to properly simulate the sulfuric acid present in acid rain.

How to Prove Acid Rain has Negative Effects on Plants

Method

1. Choose two plants of equal size from the same area or from the same parent plant, each with 10 leaves.

2. Place one plant in a test tube containing 100ml of collected rainwater (all rainwater must have been collected in the same area on the same day) and place the other in a beaker containing 100ml of distilled water.

3. To ensure reliability, make sure the plants are placed in the same place and receive equal amounts of light. Keep the room they are stored in at room temperature (28°C). To ensure that the plants receive the same amount of carbon dioxide, air should be piped through to them through a bung. Leave the plants in the same location for a week.

4. After a week observe the plants to see which one the largest number of missing or damaged leaves.

5. Repeat the experiment three times for accuracy. Record your results in a table and take the average of your results to see which plant had the largest number of dead or damaged leaves overall.


Prediction
The plant which was placed in rainwater should have a larger number of missing or damaged leaves compared to the plant that was placed in distilled water. Thus we should be able to conclude that rainwater can damage plants and reduce their rate of photosynthesis and that it could potentially have a detrimental effect on other organisms.

Equipment
*Measuring cylinders
*Test tubes.
*Rubber bung w/pipe


CORMS

C (Change): We will change whether the water surrounding the plant is acidic rainwater or neutral distilled water.


O(Organism): The organisms, the plants, must be of the same species, preferrably from the same parent plant and must have equal numbers of leaves, as well as roughly equal mass.

R(Repeat): We will repeat the experiment three times for accuracy.

M(Measure): We are measuring the number of leaves on each plant which are damaged/missing. In other words, we are measuring how much mass is damaged or lost.

S(Same): The samples must remain in the same location, and they must both receive the same amount of sunlight, carbon dioxide, and solution. The samples must be kept at room temperature (28°C).




*Rainwater may be substitued with dilute hydrochloric or sulfuric acid if normal rainwater is not acidic enough to produce a significant or measurable result in the timeframe given.

How to Reduce the Effects of Air Pollution

There are a number of ways to reduce the effects of air pollution. These include:

*Reducing the emission of sulphur dioxide and nitrous oxides from cars, either by fitting a catalytic converter to the car to reduce the volume of sulphur dioxide and nitrous oxide emitted, or by reducting the number of cars in use (ie: by encouraging people to walk or take public transport).

*Reducing the amount of sulphur dioxide and nitrous oxide released from factories, by treating the fuels before burning them or by reducing the number of fossil fuel-burning power stations in operation (ie: by encouraging the usage of renewable energy sources as opposed to non-renewable fossil fuel plants).

*Add scrubbers to domestic and industrial chimneys to neutralise acids formed.


Sunday 17 March 2013

Acid Rain: Negative Effects

Acid rain has several negative effects on organisms and structures. While normal rain is not acidic enough to have a tremendous effect, this effect can be amplified due to the gases being released in larger volumes during the combustion of fossil fuels.

Effect on Structures and Buildings
Acid rain reacts with rocks used in the creation of buildings and structures, such as sandstone, limestone and marble. This causes the affected structures to wear away and become damaged. This can cause problems in the structure of houses and buildings, or can cause statues to become disfigured.



Effect on Organisms
Being acidic, acid rain can have a negative effect on the skin and flesh of living organisms, although generally it is too mild to have an immediate effect. The effect of acid rain is much greater on the leaves of plants, causing them to die and fall off and preventing the plants from accomplishing photosynthesis. Acid rain also washes away useful minerals in soil, such as nitrates and magnesium, which has a negative effect on plants and inhibits their growth.

A build-up of acid rain in a river or other form of water supply will increase the acidity of the water, which kills local fish and animals and also increases the chance of deformities in fish.

Range of Effect


Acid rain will not necessarily occur near the source of the pollution, as the reactions which form acid rain take place in the atmosphere and wind currents can move the gases necessary for acid rain across great distances and even to other countries. Acid rain is an international problem, as pollution in one country can affect another in the form of acid rain.


Acid Rain: How is it formed?

Acid rain forms due to the combustion (burning of fossil fuels). This occurs in industrial processes such as the generation of power in coal burning power stations or during domestic processes such as driving a car. The combustion of fossil fuels releases harmful gases into the atmosphere, including sulphur dioxide and nitric oxide gases, which can react with water vapour in clouds to form sulphuric acid and nitric acid, respectively.



Although acid rain can be caused by humans, it is also a naturally occurring phenomenon: all rain is slightly acidic, due to carbon dioxide in the atmosphere reacting with water vapour in clouds to form small amounts of carbonic acid.

In short, acid rain is formed due to gases in the atmosphere reacting with water vapour in the atmosphere to form acidic substances.