lab: 2 Title: Effects of Acid Rain on Plant Growth Lecturer: Hassan Mohammad Subject Objectives: At the end of this subject student should be able to: Understand how the Acid Rain affects on Seed Germination and Seedling Growth. Scientific Content: In this subject we will cover important information about Acid Rain emphasizing its sources and effects on plants
At the end of this subject student should be able to:
Understand how theAcid Rainaffects onSeed Germination and Seedling
Growth .
Scientific Content:
In this subject we will cover important information about Acid
Rain emphasizingits sources and effects on plants
2. 3.
Precipitation that has a pH of less than that of natural
rainwater (which is about 5.6 due to dissolved carbon
dioxide).
It is formed when sulphur dioxides and nitrogen oxides, as
gases or fine particles in the atmosphere, combine with water vapor
and precipitate as sulphuric acid or nitric acid in rain, snow, or
fog.
4.
When CO 2reacts with water, carbonic acid is formed.
CO 2(g)+H 2 O(l)- H 2 CO 3 (aq)
When SO 2reacts with water, sulfurous acid is formed.
SO 2(g)+H 2 O(l)- H 2 SO 3 (aq)
WhenNO 2reacts with water, nitric acid is formed.
2NO 2 (g)+H 2 O(l)- HNO 2 (aq)+HNO 3 (aq)
5. 6.
Burning coal. Oil and natural gas in power stations makes
electricity, giving off sulphur dioxide gas.
Burning petrol and oil in vehicle engines gives off nitrogen
oxides as gases.
These gases mix with water vapour and rainwater in the
atmosphere producing weak solutions of sulphuric and nitric acids
which fall as acid rain.
7.
People probably couldn't live without
electricity! Therefore coal will continue to be burnt.
Also, electricity and energy are constantly
beingoverused.
Think of it this way: every time you turn on a
light switch or the television set without really
needing to, you're indirectly contributing to the acid rain
problem.
8.
Acid rain is an extremely destructive form of pollution, and
the environment suffers from its effects. Forests, trees, lakes,
animals, and plants suffer from acid rain.Trees
The needles and leaves of the trees turn brown and fall
off.
Trees can also suffer from stunted growth; and have damaged
bark and leaves, which makes them vulnerable to weather, disease,
and insects.
9.
All of this happens partly because of direct contact between
trees and acid rain, but it also happens when trees absorb soil
that has come into contact with acid rain.
The soil poisons the tree with toxic substances that the rain
has deposited into it.
10. MSN Encarta 11.
Lakesare also damaged by acid rain. Fish die off, and that
removes the main source of food for birds. Acid rain can even kill
fish before they are born when the eggs are laid and come into
contact with the acid.
Fish usually die only when the acid level of a lake is high;
when the acid level is lower, they can become sick, suffer stunted
growth, or lose their ability to reproduce.
Also, birds can die from eating "toxic" fish and insects.
12.
Acid rain dissolves the stonework and mortar of buildings
(especially those made out of sandstone or limestone).
It reacts with the minerals in the stone to form a powdery
substance that can be washed away by rain.
13. Currently, both the railway industry and the aeroplane
industry are having to spend a lot of money to repair the corrosive
damage done by acid rain. Also, bridges have collapsed in the past
due to acid rain corrosion. 14.
Humans can become seriously ill, and can even die from the
effects of acid rain. One of the major problems that acid rain can
cause in a human being is respiratory problems.
Many can find it difficult to breathe, especially people who
have asthma. Asthma, along with dry coughs, headaches, and throat
irritations can be caused by the sulphur dioxides and nitrogen
oxides from acid rain.
15.
Acid rain can be absorbed by both plants (through soil and/or
direct contact) and animals (from things they eat and/or direct
contact). When humans eat these plants or animals, the toxins
inside of their meals can affect them. Brain damage, kidney
problems, and Alzheimer's disease has been linked to people eating
"toxic" animals/plants.
16.
Research carried out in North America in 1982, revealed that
sulphur pollution killed 51,000 peopleand about 200,000 people
become ill as a result of the pollution.
17. What are the solutions to acid rain? 18.
1. Sulphur dioxide can be removed from power stations chimneys
but this process is expensive.
2. Reduce the amount of electricity we use
-turn TV's off at the mains, dont leave on standby.
turn off lights when a room is not in use.
3. Use renewable energy like wind power, solar panels and
geothermal energy.
4. Fit catalytic converters to vehicle exhausts which remove
the nitrogen oxides.
5. Limit the number of vehicles on the roads and increase
public transport.
19. 20.
* Seeds and Seedlings
* Filter Paper and Petri Dishes
* pH Solutions (5.5, 4.0, 3.0) and Droppers
21.
Procedure
1. Label 3 petri dishes for each pH solution. 2. Place filter
paper in each the petri dish with 10 seeds. Cover the seeds with
another piece of filter paper. Use a dropper to moisten the filter
paper through all layers with the appropriate pH solution. Put the
dishes in a sealed plastic bag and place them in a dark place. 3.
Four days later, count the number of seeds that have germinated. 4.
Measure the root length of each of the seedlings. Record
observations about seedling condition (color and overall growth and
appearance of seedling leaves). 5. Tally class averages for each pH
for germination and root length. Graph your data and the class
averages. Photograph seedlings.
22.
1. Label seedlings pots with each of the pH solutions. 2.
Measure stem and leaf lengths of seedlings. Take photos of plants.
3. Water the seedlings and moisten them each day with the
appropriate pH solution each day for two weeks. 4. Measure stem and
leaf lengths at the end of the week. Compile class data. Calculate
averages and graph data. Take photos of plants. 5. Observe leaf
color, lesions and spotting on leafs and stems, presence of dead
leafs, and any other signs of damage.
23.
Construct tables and graphs for data. Write a discussion of the
data answering the following questions. 1. What relationship did
you see between seed germination and pH? Between seedling growth
and damage and pH? 2. Some rain has been found to be as acidic as
pH 2.8. Given what you have observed, what is the likely effect on
seed germination, growth rates and plant reproduction?
