Group 4 Project
Team members: Ahmad Afandi, Firdaus Roslan, Jasmeet Maan, Pratik Raghu
Research question: To determine how the number of calcium carbonate (limestone) slots and the
design of a pH filtrate is effective in reducing the acidity of water.
Materials:
Plastic sheets, wire gauze, plastic gauze, calcium carbonate (limestone) pieces, universal
indicator, tape, strings, UHU glue, 1.0mol dm-3 hydrochloric acid, tap water.
Apparatus:
Stopwatch, retort stands, pendulum bobs, 500 cm3 measuring cylinders, 500cm3 conical flasks,
glass cover, Petri dishes, droppers, ruler, marker pen, filter funnel, wooden block.
Variables:
Chemistry aspect:
Constant variable: Size of the calcium carbonate (limestone) slot, amount of rainwater used.
Manipulated variable: Number of calcium carbonate (limestone) slots inserted.
Responding variable: Change in acidity of rainwater.
Physics aspect:
Constant variable: Height of the pH filtrate design, amount of rainwater used.
Manipulated variable: Design of the pH filtrate.
Responding variable: Speed of water flow through the filtration system.
Set-up of apparatus:
Retort
stand
String
Filter tunnel
Tube
Retort
stand
Pendulum
bob
Wooden
block
Beaker
Pendulum is placed to ensure that the tubing would be exactly vertical (90o). The distance between the
pendulum and tube is made to be constant so that they both, the string and the tubing are parallel to
each other.
Retort stands
Filter tunnel
Retort stands
Ruler
Tubing
Strings
Beaker
Pendulum bob
Sink
The tubing is slanted for 30º degrees. It is measured by using strings. A long sting was set up horizontally
as in diagram. The 2 pendulums which are 90o degrees to the string, is used to ensure that the string is
180o degree. A ruler was used to determine that the height of plastic tubing is 60cm.
Procedure:
Construction of plastic tubing:
1. 3 plastic sheets of 31cm are rolled up into tubings, each with a diameter of 4cm.
2. Using a tape, the 3 plastic tubings are attached together to form one long, vertical tubing
with a length and height of 63cm.
3. In the same way, another plastic tubing is formed. However, the length of this tubing is
made to be 72.75cm, so that when slanted at an angle of 30º, the height of the tubing
would be 63cm. This height is same as that of the vertical tubing.
Design of calcium carbonate chips (limestone) slots:
1. Using wire gauze, a cuboid shaped holder is made.
2. A layer of plastic gauze sheet is wrapped around the wire gauze using UHU glue to
ensure that the limestones are not washed away when rainwater flows.
3. Two holders are then attached using a string to represent a slot.
4. Steps 1 to 3 are repeated to form another 3 slots.
5. Strings of varying lengths are then attached to each slot.
6. Finally, limestone is added into these slots.
Simulation of rainwater:
1. 500cm3 of tap water (pH 7) is measured using a measuring cylinder.
2. 5 drops of 1.0 mol dm-3 hydrochloric acid is added into the tap water using a dropper and
the solution is poured into a 500cm3 conical flask.
3. A few squirts of the solution is poured into a petri dish and few drops of universal
indicator is added. The colour change is observed and the pH value is recorded.
Testing for number of calcium carbonate slots and design of filtrate:
1. One slot of calcium carbonate is inserted into the vertical plastic tubing.
2. Some simulated rain is poured from the conical flask into a petri dish and a few drops
of universal indicator are added to it. The change in colour is observed and the initial
pH of the rainwater is recorded.
3. The conical flask is then inverted over a round glass cover slip. The simulated
rainwater is poured into the plastic tubing through a filter funnel and the stopwatch is
started at the same time.
4. The stopwatch is stopped as the rainwater finishes flowing through the tube and is
collected in a 500cm3 measuring cylinder. The time taken for the rainwater to flow
through the tube is recorded.
5. Some of the collected rainwater is poured into a petri dish and a few drops of
universal indicator is added. The change in colour is observed and the final pH of the
rainwater is recorded.
6. Steps 1 to5 are repeated another 3 times by adding a slot of calcium carbonate into the
plastic tubing each time.
7. Steps 1 to 6 are then repeated for the slanted plastic tubing.
8. All readings are recorded and a graph of the speed of rainwater flow against the
number of calcium carbonate slots is plotted.
Data Collection:
Specifications of the vertical tube
Specifications of the slanted tube
Diameter: 4 cm
Length: 63cm
Height: 63cm
Diameter: 4 cm
Length: 72.75 cm
Height: 63cm
Vertical tube
Number of
slots
1
Initial pH, Ph
Final pH, Ph FINAL
Time, t/s
Rate of water
flow, cm3s-1
4.0
4.0
3.78
132.28
2
5.0
5.5
3.45
144.93
3
4.0
4.5
3.25
153.85
4
4.0
4.5
3.10
161.29
Number of
slots
1
INITIAL
Tube slanted at 30° to the vertical
Initial pH, Ph
Final pH, Ph FINAL
Time, t/s
INITIAL
Rate of water
flow, cm3s-1
5.0
5.0
2.87
174.22
2
4.5
4.5
2.75
181.82
3
4.5
4.5
2.72
183.82
4
4.5
4.5
2.69
185.87