YOUR BODY'S BUILDING BLOCKS
This lesson is a continuation of the Periodic Table. Previous
classes may have focused on the historical development of the Periodic Table.
Several properties and characteristics could have been discussed as well.
The lesson will focus on the building blocks of our bodies, chemical elements.
The video, Mind Your Own Body: What's A Body?, will increase the students'
awareness on how the elements affect their lives. Through a hands-on approach,
students will measure the presence of iron in the body.
Mind Your Own Body: What's A Body? (#1)
Students will be able to:
- Identify elements' symbols.
- Identify elements present in the body.
- Identify the source of several elements.
- Explain the result of element deficiencies.
- iron III thiocyanate
- potassium thiocyanate
- hydrochloric acid
- distilled water
- crucible cup
- clay triangle
- ring stand
- bunsen burner
- test tubes
- filter paper
- food items:
Divide the class into groups of 4 to 5 students. Ask the students:
Why is the table is called the Periodic Table? (Response: Repeating characteristics
and properties.) Allow students to identify these similarities among the
Ask the students: Why is the table of elements important? (Response: Everything
is made up of atoms.) Explain the make-up of water and air.
Share with the students the 13 elements which make up the human body. Write
the symbol, not the name, of each element on the chalkboard. Include the
percentage of each element present in the body. (A transparency can also
be made of this chart.)
O (Oxygen) 65% S (Sulphur) 0.25%
C (Carbon) 18% Na (Sodium) 0.15%
H (Hydrogen) 10% Cl (Chlorine) 0.15%
N (Nitrogen) 3% Mg (Magnesium) 0.05%
Ca (Calcium) 2% Fe (Iron) 0.004%
P (Phosphorus) 1.1% I (Iodine) 0.0004%
K (Potassium) 0.35%
Ask the students to name each element (O -- Oxygen, C -- Carbon, H -- Hydrogen,
N -- Nitrogen, etc.). Depending on the amount of time you wish to devote
to this activity, a competitive activity involving groups of students could
To give the students a specific responsibility while viewing,
tell them: Observe the video segment carefully and be prepared to answer
the following questions (contained on a worksheet or on the chalkboard):
1. Name three major elements in the human body.
2. What makes up a molecule?
3. Why are molecules important?
4. Explain how the elements contribute to human cells.
tape where the music video starts.
tape when the announcer says, "Cells are the building blocks for all
living things." (5 minutes)
After viewing the tape, again depending on the amount of time you wish to
spend, you may either ask the students to discuss their answers and record
them on the chalkboard, or you may collect their worksheets with the brief
answers to the four questions.
Chemistry is the study of matter, and matter is made up of the elements.
Each element is important for life and a deficiency in the 13 elements in
the human body will result in sickness.
List several elements and their sources as well as the result of a deficiency
of these elements. (Use either the chalkboard or transparencies for the
information listed below.)
Elements Important for : Source Deficiency
Sodium body fluid salted food cramps
Potassium cells / fluid fruit / milk weakness
Chlorine body fluid salted food cramps
Calcium bone / teeth dairy cramps
Phosphorus bone / teeth dairy weakness
Magnesium nerve / muscle grain / diarrhea
Iron red blood cells raisins / eggs / anemia
Flouride bone water dental
Lab: Detecting Iron in Food Samples
Read and explain the discussion and procedure.
Iron is an essential mineral needed for life because it is important for
red blood cells. The human body is made up of 0.004% iron. If one is lacking
iron, a sickness called anemia occurs. If this occurs, iron pills are taken
or foods rich in iron are increased in the diet. Iron produces an ion called
ferrous which is absorbed and used in the human body. In this experiment
you will determine which of the foods you test have the most iron, by observing
the red color of iron III thiocyanate, Fe(CN)3, formed in the food filtrate
produced. The darker the red color of the filtrate in the test tube the
more iron the food contains.
1. Place a small amount of food in a crucible (either raisins, parsley,
rice, or broccoli).
2. Place the crucible onto a clay triangle on a ring stand and remove the
water, heating with a bunsen burner.
3. Heat the food until it turns into ash.
4. Place the ash into a medium test tube.
5. Add 5 ml. of hydrochloric acid (HCl) to the test tube.
6. Stopper the tube and shake vigorously for about 1 minute.
7. Add 5 ml. of distilled water to the test tube.
8. Filter the contents of the test tube into a larger test tube.
9. Add 5 ml. of potassium thiocyanate (KSCN) solution to the test tube.
10. Place a stopper into the test tube and swirl gently.
11. Add two drops of ferric chloride (iron III chloride), FeCl3, to the
test tube and swirl.
12. Save the test tube to compare it with the other food filtrates you will
13. Repeat the above procedure with the other food samples and compare your
The material listed below may be transcribed onto student worksheets.
1. List the 4 foods in order, starting from the one with the most iron content
to the one with the least iron content.
2. Balance the equations for the reactions that take place when iron is
present in foods.
_____ Fe + _____ HCl -- _____ FeCl3 + _____ H2
_____ FeCl3 + _____ KSCN -- _____ Fe(SCN)3 + _____ KCl
3. List other minerals you can think of that are found in foods.
Write a two-page paper on how chemicals modify the food we eat.
Develop a food pyramid by substituting the elements obtained from each specific
Invite a dietitian to discuss the advantages and disadvantages of vitamins
and minerals in our diet.
Visit a health food store to examine nutritional foods.
Invite a pharmacist to discuss the history of pharmacy and the origin of
Master Teacher: Rowland V. Bynum
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