To investigate the amount of Vitamin C in fruit and fruit juices
By the end of this investigation -
Children will learn:
·that the body needs a varied and balanced diet to stay healthy
·about the nutritional disease - scurvy
·about the work of a famous scientist from the past
·how to carry out a fair test
·about different ways of averaging results - (using median values, finding the mean value).
Science investigations vocabulary
Scurvy and Vitamin C
Scurvy is a disease caused by lack of Vitamin C. Symptoms include: bleeding gums, discolouration of legs and arms and disorientation which often result in death.
Sailors in the 15th century used to get scurvy on their voyages and it was not until 18th century that the cause of this was found to be lack of Vitamin C. This was discovered by Dr. Lind, a Scottish naval surgeon in an experiment to isolate the cause and cure of the disease.
Pinpoint bleeding around hair follicles and 'corkscrew hairs can also be caused by the condition.
It is therefore very important to pay attention to our diet.
Signs of scurvy
Loss of teeth
1. Ruptured blood vessels and weeping blood from hair follicles.These signs are clearly visible in the legs of a person with scurvy.
2. Blackened loosened teeth
3. Pin point bleeding under the nails
In 1747, Dr James Lind treated sailors with scurvy by giving them oranges and lime; this achieved dramatic results. From 1795, the British Navy began to distribute regular lime juices to all sailors embarking on long voyages; this resulted in the prevention of scurvy.
Ascorbic acid or Vitamin C occurs abundantly in citrus fruits such as orange, lemon, and lime.
Fruits are essential in the diet to prevent diseases such as scurvy and in maintaining general good health.
Our Science investigation
Our investigation question: How much Vitamin C does each fruit contain?
What we will change: type of fruit
What we will keep the same: amount of DCPIP (10ml) used
: same equipment
Safety glasses or goggles
First we had to make our DCPIP solution by adding water to a teaspoonful of DCPIP granules (Dichlorphenolindophenol).
Next, we investigated the amount of Vitamin C in these fresh fruits and fruit juices.
What we did
·We collected the equipment we needed
·The teacher went through correct name of each piece of equipment
·We discussed the safety measures we needed to observe
·The teacher demonstrate correct use of equipment
·We collected our fruit and squeezed it into the beaker
·We then had to hold the pipette at 45 degrees angle in the fruit juice, squeeze the bottom to suck it up
·We then had to gently squeeze the fruit juice drop by drop into our DCPIP liquid.
·We counted how many drops before the DCPIP liquid turned colourless.
·We recorded our count
·We repeated our investigation three times to check our result
·Finally we took the median figure and recorded this.
·We tested other fruit juice using the same method.
Can you work out what safety measures we had to observe?
Our results: We found that it took the following number of fruit juice drops to turn the DCPIP colourless.
Pineapple - 42
Apple - 112
Pawpaw - 11
Oranges - 12
Lime - 19
Grapefruit - 13
Lemon – 18
We had to repeat our test three times for each fruit, we then arranged our results in order and selected the middle value and recorded this.
We tested different fruit and fruit juices. Use our results above to answer:
Which fruit has the most amount of Vitamin C?
Which has least? Which fruit has no Vitamin C?
That apple juice contains little or no Vitamin C
That papaya juice contains the most amount of Vitamin C
Do you agree with these conclusions? Why?
What conclusions would you have reached?
Evaluating our investigation method:
·How did we make our tests fair?
·How could we improve our investigation?
·Are there other ways of carrying out our tests?
·What can be learnt from the results of our tests?
·Could we use this method in any other way?
·How could we extend our learning from this investigation?
Imagine your class received this letter this morning:
My name is Zeedo and I live on planet Zezz; My friends and I at school are touring the galaxy to learn about how other beings live. We plan to visit your planet Earth but we have heard some disturbing news about eating the right food, that unless we did this, we could get ill and our body frames weaken and change. We like our bodies the way they are. Can you please let us know what we need to bring along to stop our bodies deforming?
Write a reply to the letter explaining the reason for each item you include in the list for Zeedo.