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Marymede presents their Global Experiment!

Marymede Catholic College is a P-12 school located in South Morang Victoria, Australia.  We, the year 11 Chemistry class, have participated in the Global Experiment in 2011 as it coincides with the water unit we study in VCE (Victorian Certificate of Education).

Thank you for reading our report.

                           

The year 11 Chemistry Class.

 

 

 

pH of the Planet

By: Ashley, Kaavya, Aarjoo, Alexandra 

 

Aim: To investigate and observe the pH values of a variety of water samples from different locations.

Introduction: The pH scale is used to measure the acidity of solutions. The pH of most common solutions is between 0-14. Acids commonly have relatively low pH values ranging from 0-6. By comparison bases generally have a high pH values ranging from 8-14 where 7 is neutral. The most common acid and base reactions occurs in water because water is a good solvent. Acids and base reactions are called neutralisation reactions and the measure of strengths of acids and bases depend on the extent to which they may ionise in water.

 

Junior school:

Location

pH

Inside tap-house 2 

6

Outside taps-outside house 2 

7

Girls toilets –outside house 2

6

      

Gym:

Location

pH

Outside puddles around gym

8

Inside tap of gym

7

Girls toilets in gym

8

 

Discussion: The results from Marymede’s grounds show that the samples taken from various locations such as the college Sports and Fitness centre located south west to the science department and the junior grounds located south east of the Marymede Science Department, all showed that they all had an approximately pH value that was close to neutral. The pH values that were determined ranged from 6-8. This demonstrates the samples that were tested gave a neutral pallet and hence is extremely suitable for human consumption. The junior school taps were most neutral than that of the gym ranging from 6-7. On the other hand the water samples collected from there gym ranged from 7-8 in pH.

 

Conclusion: Overall it can be concluded that Marymede’s water is suitable for human consumption as the results indicated that the water was mostly neutral rather than acidic or basic. 

 

 

 

Salty Waters

By: Joel, Amrit, Jinwar and Balraj

AIM: This activity makes use of water’s ability to dissolve substances to measure the amount of salt in some natural waters. Chemists measure the amounts of many of the substances that are present in water samples and we use the information to both understand how the world works and to keep us safe and healthy.

METHOD: Refer to Sheet (Investigating Salty Waters)

RESULTS:

Saltwater sample

Other Sample (Optional)

Mass of dish                                                m(d)                              (g)

117

1165

Volume of Saltwater                               V(sw)                            (mL)

99

98

Mass of dish and Water sample          m(d+sw)                      (g)

217

214

Drying to constant weight

 

Mass of dish and salts - 1st                                                             (g)

214

214

Mass of dish and salts - 2nd                                                           (g)

204

201

Mass of dish and salts - 3rd                                                            (g)

201

198

Final mass of dish + salts                                                                 (g)

201

198

Calculations

 

Mass of Salt                                                                                           (g)

84

83

Mass of Saltwater

100

99

Absolute salinity                                                                                 (g)

840

838.38

Density                                                                                                    (g)

1.01

1.01

Optional - Conductivity Test

Salinity from conductivity                                                             (psu)

N/A

N/A

 

DISCUSSION:

1)      Examine the dish containing the salt and see if you can see signs of crystals. Crystals glint in the light because they have flat faces that reflect light when they are big enough. You can often see the crystals better with a hand lens of simple microscope. Describe the appearance of the salt in your dish.

The salt in the dish was small, crystal like and looked like normal table salt pieces.

 

2)      The rest of the class did not undertake the experiment.

3)      The rest of the class did not undertake this experiment.

4)      When you swim in salt water how can you tell that it is denser than pure water which is slightly less than 1 g/mL at 20 Degrees Celsius.

As there is more salt in water, it causes more resistance for the person to swim in. If the water contains a very large amount of salt such as in Dead Sea, it even enables a person to float in water.

 

 

 

CONCLUSION: This experiment made us think about the properties of water in a more practical way, and explore some properties of water i.e. ability to dissolve, density etc. It also helped us discover how water reacts with some salts. Improvements we could have made is to have more people participate so that we could compare and achieve more accurate results.

 

 

Water: No dirt, No germs.

By: Bethany, Thakshini, Hannah and Marola.

Our experiment involved purifying and disinfecting water and testing this water against samples collected from various hot and tap water points throughout Marymede Catholic College, South Morang, Victoria, Australia. Also collected, were various samples of pond water located at the wetlands at the back of the school to purify and disinfect.

The sample of dirty pond water was collected on the 19th August 2011 at a lukewarm temperature located at the back of the school, in the pond at the wetlands. Before the start of the water purifying treatment, the sample of pond water was putrid in smell. The sample was yellowed in water colour, and thick with various plants which seemed to grow in the water (algae). As we conducted the process of aeration, this caused bubbles existing in the water sample to disappear completely, although the water was still discoloured and contained the pond weed and algae. Alum was added (1 tsp.) for the 100mL of water collected. The water didn’t change appearance, except after 10 minutes of the Alum being added, the water slightly became clear. This prepared the water to be ready for the process of filtration.

Filtration occurred when the pond water from the wetlands was left to filter through a white cylinder funnel, packed with gravel, coarse and fine sand. The pond water was left to filter over two days, leaving 100 mL of pure water left into a beaker. The process of water disinfection occurred however, it could be changed. The different types of chlorine strips used as the levels of chlorine recorded were different to that of what we needed, however the recorded free available chorine per million parts was calculated to be at 10ppm.

The treatment made the water clearer and fresher smelling compared to the metallic smell and appearance of the other days. The clarified water would be safe to drink had the proper chlorine levels been recorded early enough. But after disinfection, it wasn’t recommended to drink as high levels of bleach was added (4-5 drops through a pipette) through the process of clarification.

The experiment concluded with 100 mL of perfectly clean water, which was once dirty pond water from the wetlands.

 

 

Solar Still Challenge

Team Members: Peter, Anthony Matthew and Jagpreet.

Aim: To build a solar still and find out how it can purify water. When successfully completed, use your knowledge to build a more efficient solar still.

Method:

First to start the Solar Still Challenge we needed to find the equipment which was given on the sheet. The equipment that was needed was a large metal or plastic bowl but due to lack of supply we used a glass bowl, a beaker as a substitute for a shallow glass, a measuring jug, cling wrap, a small stone, food dye and salt. After assembling all the equipment, we started to put together the experiment. First we added 1cm of hot water to the glass bowl which we measured with a ruler, then added a few drops of red food dye and also a table spoon of salt. Due to cloud cover we could not successfully use the suns heat to start the process of purifying water so our group improvised and used a heated light source. We placed the beaker into the middle of the glass bowl then covered the bowl loosely with cling wrap sealing the bowl. After sealing the bowl with cling wrap we put the rock (pebble) into the middle of the cling wrap so it was positioned over the beaker underneath. We than left the experiment for a day to increase our results then checked the beaker for any purified water. After a day we measured the water and observed the colour and also tested it for salt. For part B THE DESIGN CHALLENGE we managed to find an aluminium bowl which we thought would conduct heat a lot better. We then introduced a hot plate to increase temperature throughout the bowl to increase evaporation of the water inside. We also removed the cling wrap and installed foil in its place to which we thought would be a better heat conductor.

Results:

The results for experiment Part A THE CHALLENGE was that pure water had formed in the beaker which was salt free and also clear in colour. The volume of purified water that was collected was 12.75% of the total amount which was 153 ml of water. This equalled 19.635ml of purified water in the beaker.

 In Part B THE DESIGN CHALLENGE the same mass of water was in the bowl with the same size beaker to try and give us the most accurate results. We found that the second experiment had a greater amount of purified water in the beaker which was 22.32% of the volume of the starting mass volume of the water which was 153ml (34.15ml). The still works because of the angle of the rock as its sags the cling wrap to a point which water can simply drop off into the beaker after it starts to evaporate. The still that we produced was similar in every way but the materials we used were different. The time it took for the water to evaporate was decreased astonishingly when we used the metal bowl. This is because aluminium conducts heat and we also had the hotplate underneath which sped the process up heaps.

Discussion: The results show that water can be purified in this manner and is simple and easy to accomplish at home. The results that were produced were consistent with our expectations as we read through the book let to learn more about evaporation and the water cycle. Some sources of error which may occur is the lack of sunlight or not getting enough heat to start the evaporation process. There also may be an error in setting up the experiment with lack of materials. This experiment can improve by possible changing the light and heat from the sun to help the evaporation process and instead use a heated lamp or other sources of heat to help produce better and quicker results.

Conclusion: We found water can be purified through this experiment. The water that was purified was greater and greater every time we adjusted the experiment to produce better and more accurate results. For Part A, 12.7551% was captured into the beaker and 22.317% was captured by Part B.

References: International Year of Chemistry 2011 hand book.

 

 

 

 

 

 

 

 

 


  • Comments
Well done students! What a great report.

Posted on 9/21/11 2:59 AM.

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