- Heating mantle/Hot plate x1
- Retort stand x1
- Water (50-75 litres)
- Round-bottom flask x2 (Evaporation Chamber and a spare)
- Beaker x1 (400 ml)
- Saline metre x1
- Datalogger x1
- Scissors x1
- Ruler x1 (15 cm)
- Pencil x1
- Glue gun x2
- Thermometer x1
- Masking Tape/Duct Tape x2
- Double sided tape x1
- Salt x4 packs (250 g)
- Glass stirring rod x1
- String (5 m) x 1
- 4mm rubber tubing x 10 m (all of it was used)
- Stopwatch x 1
- Measuring Cylinder (100 ml) x1
- Measuring Cylinder (250 ml) x1
- Hard aluminium foil
- Notebook x1 (Recording data)
- Measuring tape x1
- Tubing bender x1 pack (of 5) $8
- Tubing cutter x2 $10 each
- Round bottom flask holder x1 (500 ml)
- Copper pipes x9 (0.9 m x 0.355 mm) - 4 aluminium and
- Weighing balance x1 (to measure salt quantity)
- Small spoon x1
- Small circular filtration paper x7 pieces
- An extension cable x1
- Aluminium tray x2
Testing salinity level
1. Prepare a datalogger and a salinity meter.
2. Connect the data logger and the salinity meter together
3. Press the POWER button to turn the meter on.
4. Press the MODE/CAL button until the COND, SALT or TDS icon is on.
5. Connect the conductivity electrode to the side conductivity connector.
6. If required, calibrate the electrode.
7. Place the electrode in the sample solution and read the value on the display.
8. When finished, unplug the electrode and rinse in distilled water.
9. Hold the starting button of the salinity meter down
10. Connect the salinity meter to the data logger and connect the data logger to the computer using the USB cable provided. Record the data.
11. Ensure that the salinity of the saltwater is at least 35.5 ppt.
12. If not, then you can add salt to the solution
Setting up the heating mantle
1. Obtain a hot mantle.The heating mantle we are using is
and 13 cm in diameter.
2. Place the round-bottom flask on the coating of the heating mantle .
3. Using a measuring tube, measure 250 ml of water using a measuring cylinder.
4. Pour the water into the round-bottom flask.
5. Add 8.75 grams of salt into the beaker and stir vigorously to allow the salt to dissolve into the water. Prior to this, if possible, check the salinity level of the saltwater to ensure that it is similar to the salinity level of the seawater. (35.5 ppt)
6. Remember to connect the heating mantle to the main power source.
7. Turn the knob to adjust according to the variables we listed.
Note: Don't be alarmed when the orange light goes off in the middle of the experiment, it just shows that the temperature of the round bottom flask is according to the markings on the heating mantle.
Setting up the copper pipes
1.Take 9 copper pipes (4 aluminium, 5 brass etc.)
2. They can be of a length you wish. For our experiment, we obtained 90 cm copper pipes with 4mm as a diameter
3. Using a wire cutter, cut them into smaller pipes (4 mm, 44.5 cm)
The way to cut copper pipes.
4. The length of each piece of copper pipe can be varied but the recommended length will be 44.5 cm.
5. Insert the copper wire bender into the pipe A about 7 cm away from the end.
Place the wire bender on the copper pipes in this manner
6. Bend it using force (only the end into 45º) (alternate pipes only) This is to ensure that the rubber pipes do not rub against each other while conducting the experiment, also ensuring easy removing of the rubber tubings off the pipe when the experiment is completed.
Bending of copper pipes
7. Align the copper pipes in side by side horizontally.
8. Switch on the glue gun.
Glue them in a horizontal formation
9. With the help of a glue gun, glue them horizontally in a straight line in this manner.
Notice how the pipes are bent
10. Apply a little force and check if it breaks by doing a strength test.
Setting up the aluminium parts
We will be using the aluminium tray for two parts of the experiment.
1. In our case, we used the underside of the aluminium tray as it has a smooth surface, enabling the water droplets to flow into the collection beaker easily.
Bottom flat layer of this type of aluminium tray.
2. Cut a strip of aluminium with a width of 14cm and a length of 34cm. This is to be attached to the copper pipes so that water droplets can condense on the strip instead .This is so that the water droplets do not get stuck in between the gaps between the copper pipes.
3. Using a glue gun/duct tape (based on your preference). Attach the aluminium strip.
Attach the strip like this with the copper pipes being above it to keep the strip cool.
4. After attaching the strip of aluminium, cut another part of the tray .This second piece of aluminium will be in a "V-shape”. The width of the longer side will be 12cm which will be reduced to 8cm. Remember this is a V-shaped metal strip. Its length will be 19cm.
It will look like this
5. Attach this strip of metal to the heating mantle and the collection beaker with the longer side of the strip attached to the heating mantle and the smaller side attached to the condensation beaker.
Setting up the rubber tubings
- Attach one 4mm tube into the tap as shown below.
- Cut 9 x 1m length of tubes
- Connect the rubber tubes to the 5 pin rubber tubing splitters
- We will be using 4 5-pin rubber tubing splitters. 2 splitters for the input and 2 splitters for the output
- After doing that, continue connecting the tube to another 5 pin pipe splitter.
- Connect the rubber tubing to the copper pipes by inserting them into the copper pipes.
Pipe connection - Input and Output
- Make sure that the pipes do not come out due to the water pressure etc.
Rubber tubings connected to the pipe splitter
- Repeat the same procedure to ensure an output of the water
- Connect the output of the water back to the basin or you can choose to collect it in a bucket. That is according to your preference.
- Attach the pipes using duct tape to ensure security
Marking the flow rate of water
- Refer to the independent variable under introduction to know how to measure the flow rate of water.
- Place a measuring cylinder under the tap
- Obtain a stopwatch .
- Place a marking on the tap and turn the tap towards that marking.
- Start the stopwatch and place a measuring cylinder underneath the tap for 5 seconds.
- Stop the stopwatch at the 5 seconds mark and measure the amount of water collected inside the measuring cylinder.
- Note it down
- Repeat the steps above by making 2 more markings on the tap
- Name each marking as #1,#2,#3 .You can refer to the table listed below. These are the findings for our experiment, when we measured the flow rate of water.
- Switch on the heating mantle and adjust the temperature to the required value.
- Turn the tap to the required flow rate of the water.
- Adjust the angle of the copper pipes using the given method below (trigonometry)
- Once, you start all these things simultaneously, reset start the stopwatch.
- Wait for 30 minutes.
- After 30 minutes, stop the stopwatch.
- Measure the amount of water inside the collection beaker using a measuring cylinder. Note down the amount of water collected.
- Wrap a cloth around the neck of the round bottom flask to prevent burns, pick it up and pour its contents into a measuring cylinder. Note down the value. This is the amount of water left after the water evaporated.
- Total amount of water initially - Water left in the round bottom flask - Water collected = Amount of water evaporated into the surroundings
- Use this formula to calculate how much water evaporated into the surroundings. Note it down.
- Using deionised water, clean the round bottom flask to get rid of the salt residue that remained in the flask after the water evaporated.
- Wipe it dry.
- Measure the salinity of the freshwater which was in the collection beaker to ensure that it has a lower level of salinity than the water inside the round bottom flask (seawater). Refer to the steps listed above if using the datalogger is unknown to you.
- The salinity level of the freshwater (ppt) should be lower or the experiment will be deemed as a failed experiment.
- Repeat steps stated above for each and every experiment.
- Using a protractor and a board(arranged parallel to the table) we measured the angle of depression (Refer to Step 3)
Risk Assessment and Management
This is a risk assessment matrix for reference.
It can burn our fingers or hands. To avoid burns, inspect the glue gun for cracks in the handle and body. Make sure there isn't old glue clogging the nozzle. If you find any type of damage to the glue gun or to the cord, do not use it! Place the glue gun on a secure surface such as a table. Place a sheet of paper underneath it to protect the table surface. Place a piece of aluminum foil under the nozzle of the glue gun to catch the overflow of glue that will run out of the nozzle. Be sure to keep your glue gun away from open flames. Use them with extreme caution and wear cloth gloves while operating it. If there are any accidents, seek immediate medical attention and report to a teacher.
Hot Plate/Heating Mantle
The surface of the hot plate will become hot when it is in use. Someone could touch the sides and burn their hands which is what we want to prevent . We need to be careful and prevent coming into contact with the surface of the hot plate. The hot plate will only be used in the lab while we are performing the experiment and only by us. Hot water that might be spilled has to be cleaned up with a cloth immediately using a damp cloth. In case of scalding, place your hand immediately under running cold water and put antiseptic cream on the affected area. The hot plate must not be carried from its original spot when it is full of hot water so as to prevent scalding. The hot plate is only to be used under adult supervision. The water level of the liquid in the beaker on the hot plate has to be lower than the maximum mark.
The cutter will be used to cut the copper pipes, to be inserted into rubber hoses. If we are not careful, the cutter may slip and we will injure our hand, causing cuts in our skin. In the event that this happens, apply pressure to the wound. Once the bleeding has stopped, clean the wound with water an alcohol swab or antiseptic cream before applying a plaster to prevent infection of the wound. To prevent this, we will follow standard safety procedures taught to us during ADMT such as, we will not put our hand in the path of the tool or too close to the tool. We will also make sure that when we are using the wire cutters, everyone in the group will be aware.
- Create a graph with y-axis as amount of water collected and x-axis as the amount of heat applied to the seawater.
- Mark the points on the graph relating to the results of the experiment.
- Connect the lines in order of the points. At the end of the lines, label which angle is the line for.
- Using the data, find out which one is the most efficient experiment and that produced the most amount of water.
- Referring to the line graph that we will be drawing, come up with a bar chart which will explain the experiments according to the efficiency rate. This bar chart will allow us to narrow down on our 3 best experiments then derive what are the best variables when we are comparing the efficiency rates of the experiments. The graphs will be important because they will allow us to identify trends and patterns and at the same time, get the data that we need. The line graphs is to enable the reader to gauge the results effectively and also receive a brief summary of results and the experiment. In conclusion, the graphs are necessary to allow the reader to summarise our experiments and make their conclusions of our experiment just by looking at the graphs.
- After the comparisons are made, conclude how each variable affects the experiment.