Fruit Slicing /h3>

Name: Christine
Status: student
Grade: 6-8
Location: VA

Question: I am testing a banana, a peach, and an apple to see which
one will have the most percentage of water loss after being let out
for 3 hours in a room with no light and just slight air movement. i
am cutting the slices so they are 1mm thick, but how should i cut
the slices of each fruit so they are all proportionate?
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I would suggest you use a regular, easily-repeatable shape that's small
enough to be uniform (all fruit, no skin), but large enough to weigh with
good accuracy. I also suggest you consider changing your time period to be
long enough to lose a significant amount of weight.

You should try to have pieces big enough to be easily measured by your
scale. It would be great to only try to measure differences that are 10
times the accuracy of the scale. For instance, if the balance (scale) you
are using is accurate to one gram, make sure your piece of fruit is large
enough to lose at least 10 grams of water. If your scale is accurate to
0.1g, then 1 gram of loss is sufficient. If your scale is only accurate to
an ounce, then get ready to cut a lot of fruit!!

Most digital scientific balances have 0.1g accuracy (or better), so I'll use
that as an example. Assuming your fruit loses 10% of its weight and assuming
a density of 0.9 g/ml (apples float), then a 10g piece of fruit (which would
lose 1g of water) would be approximately a 2cm (3/4") cube. Target that size
or bigger.

You can also use multiple 1mm slices if you like as long as they add up to
the right weight. If you do use multiple slices, remember that exposed
surface area determines water loss, so make sure you keep them not only
uniform in size, but also the same surface area exposed.

Over a long period of time the fruit actually will lose more than 10% of its
weight, but in a short period of time like 3 hours, water loss depends on
the temperature and humidity -- it may be a lot less than 10%. If you find
that the water loss isn't much bigger than your scale's accuracy, then
either increase the amount of fruit to start, or increase the time you run
the experiment.

I also suggest you measure temperature and humidity -- these are the factors
that will influence absolute weight loss. Your experiment will get data to
compare the fruits, but if you repeat the experiment, if the temp or
humidity changes, the results could change a lot.

Hope this helps,
Burr
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