7th grade science project ideas


Science Fair Project: How to cook vegetables so that you do not lose the good vitamins

Now you can teach Mom a little about healthy cooking methods. You will learn which method causes the greatest loss of vitamin C when cooking carrots. This project gets a little involved and is probably not for the very early grades. The project requires some flair for chemistry. The project will require some facilities at a local laboratory.

Carrots store a bonanza of nutrients. No other vegetable or fruit contains as much carotene as carrots, which the body converts to vitamin A. This is versatile vegetable and an excellent source of vitamins B and C as well as calcium pectate, an extraordinary pectin fiber that has been found to have cholesterol-lowering properties.

The carrot is an herbaceous plant containing about 87% water, rich in mineral salts and vitamins (B,C,D,E). Raw carrots are an excellent source of vitamin A and potassium; they contain vitamin C, vitamin B6, thiamine, folic acid, and magnesium.

Cooked carrots are an excellent source of vitamin A, a good source of potassium, and contain vitamin B6, copper, folic acid, and magnesium. The high level of beta-carotene is very important and gives carrots their distinctive orange color.

Carrots also contain essential oils, carbohydrates and nitrogenous composites. They are well-known for their sweetening, anti-anemic, healing, diuretic, and sedative properties.

In order to assimilate the greatest quantity of the nutrients present in carrots, it is important to chew them well and they are more nutritious cooked than raw. Also most of the goodness is actually in, or just below the skin.

Ascorbic Acid also known as Vitamin C is a vitamin that can prevent some illnesses such as scurvy. It is also a vitamin that is water soluble, and fat-soluble. Vitamin C can be damaged by contact with heat, metal, air, and acids\chemicals. Vitamin C is in a lot of different foods, and drinks. A good source of vitamin C is in cantaloupe, citrus fruits, raw cabbage, strawberries, and tomatoes. Besides getting vitamin C from food, you can also get it from sunlight contact on the skin. Vitamin C is the most publicized and most difficult vitamin to understand. If you have lack of vitamin C in your diet, you will experience sore gums, and bleeding under skin. Vitamin C is needed for healthy blood vessels, bones, and teeth. Vitamin C is an organic compound of carbon, Hydrogen, and oxygen. Pure vitamin C is solid white, and is made synthetically from sugar dextrose.

Suggested materials…

1. You will need quite a few carrots for this project, perhaps twenty or so

2. Flask

3. Hand held mixer

4. 250 ml measuring cup

5. Several liters of water

6. 7 vacuum pack bags

7. Repipettor (a device that delivers an exact amount of a solution)

8. Magnetic mixer

9. Pot

10. Timer

11. Vacuum packer

12. Colander

13. Refrigerator

14. Stove

15. Labels

16. Pot

17. Analytical balance (most likely available at the high school physics, chemistry or biology department)

18. Steaming basket

Suggested procedures…

1. Prepare carrots for cooking

a. Chop carrots into 2.5 centimeter cubes

b. Thoroughly but briefly rinse the chopped carrots in cold water

2. Boil carrots

a. Put 1000 milliliters of water into a pot

b. Add 750 milliliters of carrots

c. Set temperature so pot boils continuously

d. Start timer at first boil

e. Take 250 milliliters of carrots out of the boiling water when the timer goes off at 15 minutes, continue cooking remainder

f. Take 250 milliliters of carrots out when timer goes off at 30 minutes, continue cooking remainder

g. Take 250 milliliters of carrots out at 45 minutes.

3. Package and store samples

a. Let each batch of boiled carrots cool in colander for 10 minutes

b. Vacuum pack carrots so they aren't touching any air

c. Label each vacuum pack according to the cooking method and time

d. Set the packs with the carrots in them into the refrigerator

4. Steaming carrots

a. Put 250 milliliters of water in a pot

b. Set a steaming basket above the water in the pot

c. Repeat steps 2.d - 2.g except while steaming carrots

d. Repeat step 3 for the steamed groups

5. Measure vitamin C

a. Collect a sample carrot

b. Place 600 milliliter beaker onto the electronic balance and tare, add 100.0 grams of sample

c. Add 300 milliliters of distilled or deionized water

d. Add 5 milliliters 10% H2SO4 (sulfuric acid) using a repipettor

e. Add 5 milliliters 1% starch solution to mixture

f. Titrate mixture with iodine solution to a blue-black end point that persists for not less that 20 seconds

g. Record the amount of 0.10 N iodine solution used

6. Formula for calculating vitamin C content in carrots

a. Take the squared milliliter of iodine and subtract 0.5 from it

b. Multiply that answer by 0.1

c. Multiply that answer by 88

d. divide that answer by the weight of the carrots

CLICK HERE for complete details on this project.



seventh grade science fair project ideas


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