k...Lakshmi just failed, epically :(

I guess the only good thing that came out of yesterday was that, I have errors to talk about in my discussion. u c... I didn't really think about the fact that if you put an apple in a solution it would float! Because the apples decided to float they weren't fully submerged in the solution resulting in my apples browning really weirdly. For instance the apple in the vinegar solution is really brown at the top but really white on the submerged side.... As a result of these really obscure observations & obvious errors in my experiment I have been forced to start again and am really lacking in motivation...*sigh* However, one thing I have done is....

WRITTEN UP A NEW METHOD!!!

here it is....

NEW METHOD
(Set equipment up as shown in the diagram below)

1. Get three clear, 350mL glass cups and place them on a table
2. Label one ‘A’, another ‘B’, & the other ‘C’

3. Pour 350mL of tap water into cup ‘A’
4. Pour 175mL of tap water & 175mL of vinegar into cup ‘B’ and stir the solution
5. Pour 350mL of vinegar into cup ‘C’
6. Get an apple
7. Cut it into 3 equal pieces that are 1cm in thickness
8. Place one slice of the apple carefully into each of the 3 solutions. Keep spillage to a minimum
9. Cover all three cups with a layer of cling wrap

10. Cover this layer of cling wrap with a layer of aluminium foil

11. Cover this layer of aluminium foil with cling wrap, providing a secure seal for the cup

12. Put a elastic band around the mouth of the cup so that it further secures the cling wrap/aluminium seal

13. Turn each cup from their current vertical positions to a horizontal position

14. Leave all the cups in a cool, dry place for one hour

15. Turn all cups from horizontal position to a vertical position after one hour

(Set up equipment as shown below in the diagram)

16. Get three plastic plates and place them on the table

17. Label one ‘A’, another ‘B’, & the other ‘C’

18. Remove cling wrap/aluminium seal off each cup

19. Remove the apples from the solutions using a pair of tongs

20. Place the apple from glass ‘A’ onto plate ‘A’

21. Place the apple from glass ‘B’ onto plate ‘B’

22. Place the apple from glass ‘C’ onto plate ‘C’

23. Observe apples

24. Record observations on a table like the one constructed below. Take into consideration any other significant observations. Continue the recording of observation every ten minutes for one hour.

25. Take photos of the apples every ten minutes when recoding observations & include it in recording table
26. Repeat entire experiment two more times for reliability

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…ahhhh! Now that that’s done I just need to do the experiment! I have planned to start the experiment Wednesday…after school :)

Hoping that everything goes to plan,

Lakshmi :)

LAKSHMI STARTED HER EXPERIMENTY:D!

HEHEHEHE lakshmi is very happy today as on this fine day she has completed the her experiment for her SRP :)
As of 9:30 this morning, my apples have been bathing in water, water & vingar or vinegar!
Here are the happy snappies from this great day so far...

awww....aren't they just gorgeous :)
i'll be taking photos & recording results of my apples at 10:00am everyday for one week.
so until 2morrow @ 10:00 it's good bye,
Lakshmi :)

SAYING BYE TO LEMON & HI TO WATER! :D

As you have probably realised from reading my method that I have decided not to use lemon juice.
After doing intense mathematics during my double history I realised that when you add two solutions that both have a percentage acid of 5.....your solution will still have an % acid of 5.

So this is what i mean...

% of acid in Lemon = 5%

% of acid in Vinegar = 5%

∴ IN a solution of 100mL of lemon & 100mL of vinegar there will be 5mL of acid from the lemon & 5mL from the vinegar

∴The % of acid in the solution is: (5+5) x 100 = 5%

200

pft...so as a result I have decided to use water instead! Water has a 0% of acid! So if I add the two together i should have a % acid of 2.5%....

So this is what i mean...
% of acid in Water = 0%
% of acid in Vinegar = 5%
∴ IN a solution of 100mL of water & 100mL of vinegar there will be 0mL of acid from the water & 5mL from the vinegar
∴The % of acid in the solution is: (0+5) x 100 = 2.5%
200

So! Now that I have convinced myself so much that that works....even if it doesn't im goning through with it.
So now,
I'm going to have three solutions and this is what they're gona have in each:
'A' - Water solution (200mL of water) = 0% acid
'B' - Water/ Vinegar solution (100mL of vinegar + 100mL of water) = 2.5% acid (in theory)
'C' - Vinegar solution (200mL of vinegar) = 5% acid

with the hope of starting her experiment in good time,
Lakshmi

MY METHOD!

Equipment
1 Apple
3 Glass Cups
300mL of Tap Water
300mL of Vinegar
Peeler
Cling Wrap

Method
(Set equipment up as shown in diagram below)

1. Get three medium size, clear glass cups
2. Label them as ‘A’, ‘B’ & ‘C’
3. Pour 200mL of tap water in cup ‘A’
4. Pour 100mL of tap water & 100mL of vinegar into cup ‘B’
5.Pour 200mL of vinegar into cup ‘C’
6.Get an apple
7.Peal the skin off the apple
8.Cut it into 3 equal pieces that are 3cm wide, 3cm long & 1cm thick
9.Place one slice of the apple into each of the 3 solutions
10.Cover all three cups with a layer of cling wrap & leave them in a shaded spot for 7days
11. Construct a table like the one shown below
12.Record observations of the solutions on each apple everyday at a fixed time on table (eg. 10:00am everyday). Take into consideration especially the colour & texture of the apple

13. Take photo of solution when recoding observations & include it of recording table everyday
14.Repeat entire experiment two more times for reliability

SOME CONDITIONS APPLY....

MISS ZHANG HAS APPROVED MY IDEA!!!
BUT SOME CONDITIONS APPLY....
So apart from being very happy that I hv finally gotten the thumbs up....i need to change a couple of things.
Miss Zhang told me to only use one variable. So that's what I'm going to do!
I am going to only test the effect of the apple on a vinegar solution.
However, i'm going to test it on solutions of vinegar with varing amounts of acidity
In one cup I'm going to have just vinegar, and in the other 3 cups i'm going to increase the values of lemon juice at a constant rate to increase the percentage of acidity in each solution.
I researched the percentage of acid in vinegar and lemon. It turns out that vinegar is made up of 5% acid, while lemon is made of 5-6% acid.

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RESEARCH

Vinegar: (www.buzzle.com/articles/vinegar-ph-of-vinegar.html)
...The pH of vinegar depends upon how much acid is present in it. The most commercial distilled white vinegars contain 5% acetic acid and so have a pH value that is somewhere between 2.40 - 3.40....


Lemon: (http://www.herbs2000.com/herbs/herbs_lemon.htm)
...Citric acid also makes up about five to six per cent of the juice and tissues of lemons and limes, this percentage is very high compared to oranges at about one to one and a half percent, or the grapefruit, at about one to two percent citric acid...


I also researched the pH of a substance is determined...
(www.chem4kids.com/files/react_acidbase.html)
That pH scale we talked about is actually a measure of the number of H+ ions in a solution. If there are a lot of H+ ions, the pH is very low. If there are a lot of OH- ions, that means the number of H+ ions is very low, so the pH is high. Think about it for a second. Why would a liquid with high levels of NaOH be dangerous and very basic? The Na-OH bond breaks in solution and you have sodium ions (+) and hydroxide ions (-). The sodium ions don't really pose a danger in solution, but there are a huge number of hydroxide ions in solution compared to the hydrogen ions. All of those excess OH- ions make the pH super-high and the solution will readily react with many compounds. The same thing happens on a less dangerous scale when you add baking soda to water. OH- ions are released in the solution. The numbers of OH- are greater than the H+ and the pH decreases.

I also researched the enzymatic browning reaction of cut apples....(http://www.curriculumsupport.education.nsw.gov.au/secondary/science/assets/aifst/Experiments/apple_browning.pdf)
When fruits or vegetables are peeled or cut, enzymes contained in the plant cells are released. In the presence of oxygen from the air, the enzyme phenolase catalyses one step in the biochemical conversion of plant phenolic compounds to form brown pigments known as melanins. This reaction, called enzymatic browning, occurs readily at warm temperatures when the pH is between 5.0 and 7.0.

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