EXPERIMENTO INGLES

EXPERIMENT 1

OBJECTIVE: To determine the comparative amountof vitamin C in oranges and lemons

MATERIALS:

• 3 250 ml glass beakers

• 3 small test tubes

• Paper to record test results

• 1 stirring rod

• 3 medicine droppers

• Safety gloves

• A laboratory coat

• Cup of water

• Orange juice

• Lemon juice

METHOD

First, make an Indophenol solution by combining 7 drops of Indophenol with one cup of water. Stir, using the stirring rod, until it well mixed.

Next, put 15 drops of Indophenol solution into a test tube.

Then add a drop of orange juice to the Indophenol using the medicine dropper.

Continue adding drops of orange juice. Count the number of drops you need to add before the indicator loses all of its color. Don´t forget to shake gently after adding each drop.

Next, record your data on a piece of paper. How many drops did it take to turn the blue Indophenol colorless?

Number of drops needed to turn the solution colorless

Orange juice 28

Lemon

Next, repeat the procedure with the lemon juice.

Now it is to analyze your data. The fewer drops of juice you need for the color to change, the higher the vitamin C content in the juice. What do the results demonstrate?

Number of drops needed to turn the solution colorless

Orange juice 28

Lemon 69

There are many variations of this experiment. For example, you can test how vitamin C content is affected by variables such as methods of processing (canning, freezing, etc.) or storage conditions (exposure to heat, light, and metals).

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