SNC 4E: Nutritional ScienceTeacher Demo/Student Activity: Iron in CerealTopics

Food nutrients and additives

Timing

preparation: 5 minutes

demonstration/activity: 10-15 minutes

Specific Expectations SNC4EIntroduction

Food labels often contain the word fortified. This means that one or more ingredients have been added that are not normally found in that food item. The purpose is to increase the amount of that mineral or nutrient to serve a dietary purpose. Table salt is fortified with iodine (to help prevent hypothyroidism, which can lead to goiter which is the abnormal enlargement of the thyroid gland), and many breakfast cereals are fortified with fibre (to improve digestion) and iron.

Iron ions (Fe3+) are essential for the formation of red blood cells. They are central to the hemoglobin molecule, which is responsible for the transfer of oxygen gas and carbon dioxide throughout the body. Iron ions are also found in muscle tissue and many enzymes. Iron is often added to cereal in its elemental form (Fe) because it is more stable and has a minimal effect on flavor.

The recommended daily intake of iron depends on age and gender. These values are listed in the Additional Resources section, and information about iron content in food can be found in the nutritional facts label on the packaging.

The purpose of this demonstration/activity is to illustrate the importance of proper labeling and identification of substances and the presence and form of iron in breakfast cereals.

Materials

Strong magnet painted white (e.g. magnetic stir bar magnet) or neodymium magnet

Re-sealable clear sandwich bag

Approximately 1 cup of cereal high in iron or fortified with iron (see Teaching Suggestions/Hints for examples)

Safety Considerations

The cereal should not be ingested, as it may be stored in the laboratory and may have been used for this or other demonstrations previously.

Procedure

Preparation

1. Place a serving of cereal in a re-sealable sandwich bag. Crush the cereal into powder and small crumb-like pieces.

2. Make copies of the Nutrition Facts label from the cereal container.

Minds On

3. Organize your class into pairs. They will also need a page to record their thoughts.

4. Give each pair of students a copy of the Nutrition Facts label for the cereal used for the demonstration.

5. Review the steps of the demonstration. Explain that the cereal has been crushed. Students may want to inspect the bag. Remind them that this cereal is not safe to eat.

6. Ask students to look for any nutrient that would react with a magnet.

Predict/Explain

7. Once students have identified iron as the key nutrient, as them to predict what will happen when the when the magnet is placed in the cereal. Drawing a diagram might make this easier for the students.

8. Ask each group to record an explanation of their prediction and then give reasons for this.

Demonstration:

9. Place the magnetic stir bar into the bag and seal the bag closed. Shake the bag vigorously for 30 seconds to 1 minute. Lift out the magnet carefully.

Observe

10. Conduct the demonstration and provide time for students to record their observations.

Explain

11. Ask students to complete their observations of the demonstration.

12. Pairs of students can then review their predictions and reasoning and record revisions.

13. Where appropriate, ask students to share their findings.

Disposal

The cereal can be disposed of in the regular garbage or municipal organic waste if available.

What happens?

Elemental iron has been added to foods for many years. The crushing process helps to release the iron so that the magnet can collect it.

A neodymium magnet is very strong and should not be used by the students without supervision.

Small black flecks visible on the white coated magnet are elemental iron.

How does it work?

The magnet will attract the iron flakes found in the cereal. Iron is added to cereal as elemental solid iron, Fe. Once it is consumed, it is digested in the stomach and converted to iron ions, Fe3+, which is the form used in the human body.

Teaching Suggestions/Hints

1. This can either be performed as a teacher-centered demonstration or a student-centered activity.

2. Try this demonstration/activity beforehand to ensure visible black iron flakes can be extracted. Try different types or brands of cereal if necessary, and consider modifying the method depending on the type of cereal. See the Additional Resources section for alternative methods.

3. A coated neodymium magnet is available from science supply companies.

4. Look at the nutritional information on the cereal package to determine the iron content. Examples of cereal types that are high in iron (30-50% of recommended adult daily intake) are flakes (bran or corn), oat rings (i.e. General Mills Cheerios), Kelloggs Just Right or Shreddies. Infant and childrens cereals are often fortified and contain 100% of the recommended child daily intake, which is between 7-11 mg per serving.

5. Cattle eat grasses in the field or as hay. Sometimes cattle will ingest iron scraps. Cow magnets are placed in the rumen of the digestive tract to attract scrap bits away from delicate areas that could be damaged.

Next Steps

This activity/demonstration can be used to introduce the concept of nutritional content of foods, specifically minerals that are found in food and dietary supplements. It can be followed up with an inquiry investigating the presence of various nutrients in foods (e.g., starch, simple sugars, fats, proteins).

Additional Resources

1. A similar experiment from Steve Spangler science: http://www.stevespanglerscience.com/lab/experiments/eating-nails-for-breakfast

2. Information about the importance of iron in our diet and recommended daily intake values: http://www.eatrightontario.ca/en/Articles/Nutrients-(vitamins-and-minerals)/Iron-Matters.aspx

3. Learn more about iron in food here: http://www.cmaj.ca/content/168/9/1109.2.full

4. Cereal flakes can directly connect to a strong magnet: https://www.youtube.com/watch?v=T2jFace9D7o

5. Canadas Food Guide: http://www.hc-sc.gc.ca/fn-an/food-guide-aliment/index-eng.php

Specific Expectations

SNC4E

A1.1 formulate relevant scientific questions about observed relationships, ideas, problems, or issues, make informed predictions, and/or formulate educated hypotheses to focus inquiries or research

A1.11 communicate ideas, plans, procedures, results, and conclusions orally, in writing, and/or in electronic presentations, using appropriate language and a variety of formats (e.g., data tables, laboratory reports, presentations, debates, simulations, models)

F2.3 conduct an investigation to test for the presence of various nutrients in foods (e.g., use iodine to test for starch; use Benedicts solution to test for simple sugar)

F3.1 identify sources of the principal food nutrients (e.g., carbohydrates, lipids, proteins, vitamins, minerals, fibre), with reference to Canadas Food Guide, and describe the function of these nutrients in the body

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