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The Vitamin C content in fruits

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Introduction

´╗┐Title: The Vitamin C content in fruits Aim: To investigate and compare the vitamin C concentration in the juices of some common fruits Introduction Problem: Which type of fruits has the highest vitamin C content? Design of investigation: In order to compare the vitamin C concentration in the juices of different fruits, we need to measure the the number of drops of each fruit juice required to make a constant volume of DCPIP solution change from blue to colourless. The independent variable is the different types of fruit juice .To manipulate the independent variable,we can buy different types of common fruits from the supermarket.We can obtain the fruit juice by grinding the fruit pieces with a small quantity of distilled water. The dependent variable is the concentration of vitamin C in different fruits.The concentration of vitamin C in different fruits can be compared by measuring the number of drops of each fruit juice required ...read more.

Middle

Materials:30ml of 1% DCPIP solution,kiwifruit,orange,green grapes,lemon Procedure: Cut the kiwifruit,orange,green grapes and lemon into small pieces. Grind the small pieces of each fruit with 2ml of distilled water Squeeze the extract of each fruit through a filter cloth and put the extracts into respective test tubes. Pipette 1ml of 1%DCPIP solution to each test tube. Suck each sample of fruit juice by using a dropper and add in each sample of juice drop by drop to the DCPIP solution in each test tube until the blue colour fades to colourless. Record the drops of each fruit juice used to decolourise the DCPIP solution Repeat steps 4 to 6 two times to record the average number of drops of juice used. Precautions: The pipette must be cleaned with distilled water and rinsed by the DCPIP solution before used to transfer the solution. ...read more.

Conclusion

The fewer drops of juice used to decolourise the DCPIP solution, the higher the concentration of Vitamin C in the fruit juice.It shows that orange has the highest vitamin C concentration , then it is lemon and kiwifruit.Green grape has the least vitamin C concentration. The following are the source of error of the experiment: There might be personal error when adding drops of juice as the size of drops might not be the same. A lot of drops of green grape juice are needed to turn the DCPIP solution to colourless which is hard to record and determine. There might be heat transfer to the juice during the experiment which would affect the vitamin C content. To increase the accuracy of the experiment,we can do the followings: 1.Repeat the experiment a few times and take the average reading. 2.Dilute the DCPIP solution to a certain concentration before adding fruit juice into it. Conclusion: Orange has the highest vitamin C content among the fruits we had examined. ...read more.

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Here's what a teacher thought of this essay

3 star(s)

This is a good attempt at an essay:
1. The variable sections are detailed and have been thought through.
2. The summarizing of the practical is good.
3. The use of language is appropriate throughout.
4. The results table should include an average section.
5. The conclusion section needs to be revisited to explain the pattern and to move information to an evaluation section.
*** (3 stars)

Marked by teacher Luke Smithen 24/04/2013

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