Refractometer Catagories

Science Projects Using Apples & a Refractometer

[ 2015-4-9 ]

Projects with apples are a fun way of learning scientific principles. The refractometer is a safe instrument that does not require the use of chemicals. It measures the refractive index of light, and can also be used to measure the sugar content (or salinity) of a liquid. Plan your projects around the testing of the sugar content. Learning to use a refractometer can be a separate project.

Testing for Sweetness
Choose four different varieties of apples. Predict which variety you think would be the sweetest. Gather the materials. Take a hand-held refractometer and at least three apples of each variety. Also get a knife, cheesecloth or juicer, four pipettes and soft tissue. Slice an apple, juice it. Use the pipette to put two drops on the refractometer. Read and note the Degree Brie (unit that measures amount of sugar). Repeat with the other two apples of the same variety to get an average of the sugar reading. Wipe clean the refractometer, and repeat the procedure for the other varieties, making sure to take a fresh pipette and clean the lens before changing varieties. Look at the final four averages to see which variety is the sweetest.

Testing for Ripening
Start with six unripe apples of any one variety, as nearly similar in ripeness as possible. Store them all in the same environment. Take one apple, and repeat the methodology of the first test. Record the three readings and average for day one. Repeat with another apple from the lot after four days. Follow this regimen of testing with another fruit every fifth day until all the apples are done. Chart a graph to see if the sugar content was rising over time (ripening).

Testing for Ripening When Stored
Take 12 apples as nearly of the same degree of unripeness as possible. Store six apples in a paper bag, and the remainder in a sealed plastic bag. Repeat the test for ripening apples. See which apples ripen faster --the ones in paper bags, or the apples in plastic bags.

Does One Rotten Apple Spoil the Barrel?
Take two dozen apples, of as similar ripeness as possible. Divide them in two baskets with lids and place the baskets in the exact same environment, but not next to each other. In one of the baskets add a spoiled (bruised) apple. Leave the other basket alone. Conduct the test for ripening. If you see the apples ripening faster than the four-day spread then test at shorter intervals. Since a spoiled apple releases ethylene, which is responsible for the ripening, it will indeed hasten the ripening process. The apples in the other container will not ripen as soon.