Appendix- Evidence of Trial Experiment or Testing of Prototype

This is my brainstorming process for the SIP:

• What materials can i use as suitable filters in a simple water filtration system?

After some research on homemade water filtration systems, i came to a conclusion that sand and cotton were among one of the most commonly used filters in water filtration systems and are also easy to obtain. Hence, i decided to test these two filters in the water filtration system that i had created to observe which was the better filter

• How can i create the water filtration system?

These are the diagrams which display the steps to create the water filtration system.

Step 1: Choose 2 clean bottles

Step 2: Cut one bottle into two segments, with the top segment taking up ¼ of the bottle and the bottom segment taking up ¾ of the bottle.

Step 3:  Cut the other bottle into two segments, with the top segment taking up ¾ of the bottle and the bottom segment taking up ¼ of the bottle

 

Step 4: Invert the top segment from step 3 and fit it into the bottom segment in step 2.

Step 5: Invert the top segment from step 2 and fit it on the top.The final product should look like this.

• Testing of prototype

Step 1: Name the 3 filtration systems “Control” “Set-up 1” and “Set-up 2” respectively

Step 2: In the control, place filter paper at both funnels

Step 3: Pour 50ml of dirty water into the top funnel

This is the difference between the contaminated
water (in the large bottle) and the filtered '
water (in the 50ml beaker)

Step 4: Wait for all the water to drip to the bottom of the filtration system

Step 5: Measure the pH level of the filtered water. 

Step 6: Add 20ml of sand onto both filter papers and repeat steps 2 – 5 for set-up 1

Step 7: Add cotton onto both filter papers and repeat steps 2 – 3 for set up 2.

Chemistry Practical #2 [15 January 2013]

For today's practical session in the chemistry lab, we had conduct an experiment to find out the difference between "Mixtures" and "Compounds".

For the first part of the lab session, we conducted an experiment with metallic grey iron fillings and yellow sulfur powder. Firstly, we poured one spatula of iron fillings and one spatula of sulfur onto a filter paper. Then, we used a mixer to mix them together. They were able to mix in any proportion to form a mixture.

The bottom of the filter paper, where the mixture was, did not feel warm because it was a mixture, and not a chemical reaction, which might cause the bottom of the filter paper to either feel warmer or colder than before.

Then, we moved a magnet under the filter paper and the magnet was able to separate the magnetic iron filling from the non-magnetic sulphur.

Next, we added the iron and sulfur into a test-tube of distilled water and stirred it before letting it stand for awhile. We noticed that the iron fillings gathered at the bottom of the test tube while some of the sulphur rested on top of the iron fillings, or on the surface of the distilled water.

The iron fillings and the sulfur acted as separate substance with water  and this proved that water does not separate the mixture of elements as they are both insoluble in water.

After this experiment, we concluded that:

1. the substance in a mixture can be mixed in any proportion
2. When a mixture is formed, hear and light are not usually taken in or given out
3. The mixture can be separated by physical means (With a magnet)
4. The mixture has/retains the properties of its constituent substances.

For the second part of the lab session, we conducted an experiment to observe the difference between "Mixtures" and "Compounds".

Firstly, we mixed one spatula of sulfur and half a spatula of iron fillings in a crucible. Then, we covered the crucible with a lid and heated it for ten minutes using a strong flame. 

After ten minutes, we waited for the crucible to cool down, before opening the lid to observe the residue left. This is what we observed:

1. The residue was hard and black solid
2. It combined and was not the same powdery form it was originally

Then, we scraped out some residue from the bottom of the crucible onto a filter paper and tested it using a magnet. This time, the iron didn't separate from the sulfur as the new residue had lost its magnetic properties because it did not retain the properties of iron anymore.

Then we crush the residue into small pieces and added them to distilled water inside a test-tube. After stirring it for a while, we allowed it to stand and observed it. The mixture sinked to the bottom while the residue floated on the surface of the distilled water.

Hence, we concluded that the residue formed is a compound as properties of a compound has different physical properties as its constituent elements. A compound cannot be separated by physical means (like a magnet) and a chemical reaction takes place when a compound is formed when there is an energy change ( The residue was warmer and harder than it's original powdery state )

We also answered a question where a student decided to repeat the second part of the experiment (Which is the second half of the lab session) with not half, but one spatula of sulfur and one spatula of iron fillings. This is our prediction on what the student will observe:

1. The appearance of the residue in the crucible would be a mixture of the black powder and excess iron fillings
2. The magnet would be able to separate the iron fillings from the black powder
3. The grey iron fillings and the black powder will remain insoluble in water and will sink down.

This is the explanation for our prediction:

Both iron and the new compound are insoluble in water, and hence, they produce a suspension as observed.

There was also an extension question which stated that we are given a solid mixture of common salt, sulfur powder and iron fillings. We were asked to describe how we will separate those 3 substances. Here are the steps:

1. Use  magnet to separate the iron fillings from the mixture
2. Add water to the remaining mixture and stir
3. Ensure that the salt has been dissolved
4. Filter away the salt and water mixture to get the sulfur powder (Filtering separates insoluble substances from soluble ones)
5. Evaporate the water to leave the salt behind and dry it in the sun
6. Dry the sulfur powder with filter paper by squeezing it and drying it under a fan.

That was the end of our lab session.