2. Methods

2.1 Equipment List

Our equipment and materials used are as follows:

Items
Quantity required
Usage
Where or who to obtain from
Requirement(s) (if any)
Sea salt
81.00g
Act as a pollutant for the experiment. To be added in the set-ups.
To be obtained from science research lab
NIL
Plastic containers
19
To store and keep the duckweed and salt mixture in.
From E-Shean
Transparent/Translucent. (to allow some light to pass through).
Shrink wrap/ Cling wrap
1 roll
To cover the set-ups
Bought by E-Shean
NIL
Lamps
4
Used as an artificial light source to ensure plant growth.
School engineering lab
NIL
Cardboard
1 piece
Place all the set-ups on.
To be brought by E-Shean
Be able to hold all the containers (set-ups)
Plastic disposable party spoons
20 (1 for 1 set-up and 1 for salt.)
Used as stirrers or to scoop anything up
Bought by E-Shean
At least 1 for each set-up.
Weighing scale
1
Weigh the amount of salt to be placed in each container
To be obtained from science engineering lab
0.00 precision  (best)
Measuring cylinder and syringe
1
Measure the amount of pond water in each container
To be obtained from science engineering lab
Measuring cylinder - measure up to 200ml or more.
Duckweed
152 individual leaves
Most important prospect, to be placed in every set-up.
To be obtained by Yi Zhen from near her house.
NIL




2.2 Diagrams of experimental setup  

Fig. 2.1: A diagram explaining our procedure. The diagram labels the components of a container of the set-up (that will be applied for all the set-ups). This figure will ensure that we will not go wrong when setting up.


Fig. 3.1: Overall set-up shown above. 6+1 main set-ups. For it to be a fair test, it would be 1+2 for each set-up, then we can proceed on to find the average.



2.3 Procedures

  1. 19 transparent/translucent containers will be used for this experiment. One container will be used as the control set-up. The control set-up will not contain any salt (0.00g).The rest of the containers will receive varied amounts of salt. The salt used in this experiment will be Sea Salt. The Salt used will stay constant throughout the experiment. The containers will be labelled (A1, A2, A3, B1, B2… … ) accordingly. Set- up (A) will receive (2.00g) of salt, Set-up (B) will receive (3.00g) of salt and so and so on (refer to table below). For each label (as in “A”, “B”, “C”, e.t.c.), there are 3 container set-ups to take the average
  2. Measure the salt using a weighing scale and ensure that it has at least 0.00 precision for optimal usage and accuracy.
  3. Lay out all 19 containers in the order of: A1, A2, A3, B1 … , E3, F1, F2, F3, CS1 on the cardboard piece.
  4. Measure out 200ml of water and pour it into the individual containers
  5. As one person pours the measured out salt into the water, another person will use the plastic spoons to stir the salt in order for it dissolve in the water.
  6. Each set-up will receive 8 duckweeds.
  7. Poke holes in the shrink wrap and tear it out. Wrap the mouths of the containers with the shrink wrap.
  8. All the containers will be left on top of the side cabinets at the school lab and we will check on it on Day 6, which gives it enough time to grow and to show any obvious changes that can be seen by the naked eye.
  9. On Day 6 of the experiment, we will once again, check on the set-ups. On that day, we will take down the number of leaves and any observations/remarks into the table in the shared spreadsheet.

Beaker (200ml in size)
Amount of Salt Received (In grams)
Water (In ml)
(Control Set-Up) CS1
0.00
200 ml of water
A1
2.00
200 ml of water
A2
2.00
200 ml of water
A3
2.00
200 ml of water
B1
3.00
200 ml of water
B2
3.00
200 ml of water
B3
3.00
200 ml of water
C1
4.00
200 ml of water
C2
4.00
200 ml of water
C3
4.00
200 ml of water
D1
5.00
200 ml of water
D2
5.00
200 ml of water
D3
5.00
200 ml of water
E1
6.00
200 ml of water
E2
6.00
200 ml of water
E3
6.00
200 ml of water
F1
7.00
200 ml of water
F2
7.00
200 ml of water
F3
7.00
200 ml of water

Figure 4.1: Shown above is a table pertaining the data of each set-up. It shows how much salt:water there is in each set-up and is a table form of figure 2.1 that is seen on page 5.



2.4 Risk Assessment and Management  

Risk
Assessment
Management
Spilled water (When setting up experiment) may be a slipping hazard and can cause us to be seriously injured. (to a certain extent)
Medium
Be careful when setting up experiment, ensure that other group members are around before starting with the experiment so as to look out for each other and assist each other when the risk occurs (wipe up the water)
When poking holes into the shrink wrap, ensure that one is careful to not poke oneself (because we are using a sharp object e.g. pen)
Low
Do not point the sharp tip of the item used to poke the shrink wrap at other people and have a chaperone look out for you at all times when handling the sharp object
When dealing with salt water, some of the saline water may enter our eyes or open wounds, which may cause us some degree of hurt and pain.
Medium
Ensure that we do not allow any opportunities for the salt water to enter our eyes or open wounds. Also, we must be more careful when dealing with water with higher concentrations of salt.
Mosquitoes may breed in the water that contains the duckweed (stagnant water left for a long amount of time). The mosquitoes may cause a spread of diseases such as dengue.
Medium
We will use shrink wrap to prevent the breeding of mosquitoes. There will be small holes poked onto the surface of the shrink wrap to allow airflow while preventing the breeding of mosquitoes in the container being used.
As we are using artificial light sources for our experiment and the fact that water will be utilized for the experiment might lead to the risk of electrocution. Less there be a water spillage, we might risk getting electrocuted.
Medium
Firstly, the shrink wrap used will minimize the flow of water if a set-up falls over. Secondly, during the real experiment, we will place the set-ups onto a piece of cardboard, reducing the risk of others bumping into it while absorbing some of the water into itself. Thirdly, we can move the light sources away when setting up the experiment.

2.5 Data Analysis

  1. On the day we start the experiment, we will take photos of each individual set-up. On the day we end the experiment or when we check on the containers, we will also take photos of each individual set-up to compare with the first set of photos. Someone will also key in the data collected – namely the number of leaves – into the table with observations on the growth of the duckweed or any remarks we have.
  2. All the data are to be keyed in on Day 6 of the experiment into the shared spreadsheet.
  3. Note down any big or distinct changes in the remarks/observation session of the table in the shared spreadsheet (e.g. observation of withered leaves or a reduced growth rate of the plant, etcetera).
  4. Plot a curved line graph on the number of leaves counted from step 1. This graph will utilize the information in the shared spreadsheet – namely the table where all the data will be collated in. Tidy up the final table using numbers. For the graph, use any software required to plot the most accurate graph.
  5. Refer to both the graph and table to observe the changes in the duckweed plant in accordance to the different amounts of salt to decide whether it would be suitable and effective as a bioindicator.

No comments:

Post a Comment