Nutrition Label Activity

May 25, 2018 | 8:05 am

In Search of Essential Nutrients

Nutrition Label Activity 

Grade Levels: 5-12

Time: 45 minutes

Group Size: 30

This activity is a mix of Lesson 1 in the High School/Middle School curriculum and a health lesson. 

 

Brief Description: Students explore the meaning of essential nutrients, using periodic tables to compare the elements that are essential to people and plants. Students make predictions as to where in the environment plants obtain each of their essential elements.

 

 Subjects Taught: Science, Language Arts

 

Objectives: The students will:

  1. Define an essential element;
  2. Compare and contrast the essential nutrient requirements of plants and humans;
  3. Explain why plants cannot use elemental nitrogen found in the atmosphere; and
  4. Identify the sources for each essential nutrient needed by plants.

 

Materials Needed:

Provide nutrition labels from boxes of cereal (or photocopies), like Quaker Oats® Breakfast Bars, which feature phosphorus and potassium on the label or Cheerios®.  Also, have a nutrition label from a snack food, such as a candy bar.

 

Prepare the images from Masters 1.1 to 1.6.

Colored Pencils – one per student

Venn Diagram – Essential Nutrients Answer Key

Projectable images from Nourishing the Planet in the 21st Century:

Master 1.1, Essential Nutrients

Master 1.2, The Periodic Table

Master 1.4, Essential Plant Nutrients

Master 1.5, Essential Human Nutrients

Master 1.6, Sources of Essential Nutrients

One photocopy per student:

Master 1.2, The Periodic Table

Master 1.3, Chemical Symbols of the Elements

Master 1.6, Sources of Essential Nutrients 

 

Background Information: There are more than 100 known elements that combine in a multitude of ways to produce compounds, which account for the living and nonliving substances we encounter. Out of that list of 100 elements, plants require 17 essential nutrients to complete their life cycles; germinate, grow, build tissue, flower, pollinate, produce seed or vegetative structures to reproduce (runners, tubers, bulbs, rhizomes, etc.) and/or survive cold or dry periods.  A nutrient is considered essential if it is required by the plant to complete its life cycle, cannot be replaced by another nutrient, is directly involved in the plant’s metabolism, and is required by many different plants. These nutrients are identified on Master 1-4. Plants that grow on land obtain these nutrients from air, water and soil.

Cells carry on the many functions needed to sustain life. This requires that they take in nutrients, which they use to provide energy for the work that cells do and to make the materials that a cell or organism needs. Plants and humans require similar sets of essential nutrients.  The essential nutrients needed by humans are identified on Master 1-05.

In the context of plant requirements, carbon, oxygen, and hydrogen are called the non-mineral nutrients. Some essential nutrients are obtained from more than one source. For the purpose of this activity, you want students to realize that plants obtain their nonmineral nutrients (carbon, hydrogen, and oxygen) from the air and water, while the rest come from the soil.

 

Activity One: Essential Nutrients

 

  1. Begin the lesson by explaining that scientists who are interested in studying human health must understand the specific needs of the body. Ask:

“What do humans need to live?”(Answers will vary.) Accept all answers.

  1. Write student responses on the board, on an overhead transparency, or using an electronic board.
  2. Direct the discussion to elicit air (oxygen), water, and food. Some students may realize that sleep is also required for survival. Other students may suggest environmental conditions such as temperature and pressure or material things such as clothing and shelter.
  3. Remind students that life requires energy for its existence. Ask students:

 

“What do people take into their bodies from their environment to help them survive?”

(Students should recognize from their previous answers that air, water, and food are obtained from the environment.)

 

“What do we need from the air?” (It is the oxygen in the air that we require.)

 

“Why do we need water? (Students should be able to explain that our cells are mostly made of water. Water is the medium in which life has evolved. It is required for the chemistry of life.)

 

“Why do we need food to survive?” (Students should recognize that we derive chemical energy from food and that food supplies the chemical building blocks needed by our cells.)

  1. Remind students that humans (and animals) eat plants and other animals to obtain chemical energy and provide them with the building blocks needed by their cells. Ask:

 

“Do plants need food?” (No, not in the sense that humans or other animals eat food. Plants do not eat. Plants make food from minerals, water, and gasses. Plants do need nutrients.  What may be commonly be called “plant food” is actually fertilizer.)  Make sure students realize that PLANTS DO NOT EAT! Plants absorb nutrients from soil as they take in water.  Plants absorb carbon dioxide through their leaves from the atmosphere during photosynthesis.

  1. Explain that they will now investigate the chemical elements that are essential for plant growth.
  2. Display an image of Master 1.1, Essential Nutrients.
  3. Ask different students to read aloud the criteria that describe an essential element.
  4. Pass out a copy of Master 1.2, The Periodic Table and a copy of Master 1.3, Chemical Symbols of the Elements to each student.
  5. Instruct the class to think about the definition of “essential element” and use a colored pencil to shade those elements on the periodic table that they think are essential for healthy plant growth based on the information they have learned in the past.
  6. If possible, students should think of an example of how a given element is used by the plant (such as nitrogen being used to make protein).
  7. Give students about 5 minutes to complete this task. This step gives you an opportunity to assess how well students can relate their knowledge of chemistry to biology. For example, students may respond that carbon is used to make sugar. Students likely will not be able to suggest a function for elements needed in trace amounts. Usually, such elements are needed as cofactors for enzymes. It is not important to discuss the uses of each element, but it is important that students understand that these elements are needed to build cell structures and to carry out the cell’s chemistry through enzymatic reactions.
  8. Display an image of Master 1.2, The Periodic Table.
  9. Ask a student volunteer to read aloud the elements shaded on his or her periodic table. b. Have the volunteer explain why he or she selected those particular elements.
  10. Have additional students add to the list with their predictions.
  11. As the elements are read off, circle them on the image.
  12. Students are not expected to identify the complete list of essential elements. Their responses, however, will reflect their relative knowledge about the biology of plants.
  13. Explain that you are now going to reveal which elements have been shown to be essential for plant growth and compare them with students’ predictions. Display an image of Master 1.4, Essential Plant Nutrients.
  14. Students likely will be surprised that so many elements are essential for plant growth.
  15. The comparison between the elements predicted by the students and the accepted ones should show some overlap, especially among the most abundant elements: carbon (C), hydrogen (H), nitrogen (N), oxygen (O), phosphorus (P), and sulfur (S).
  16. If not already mentioned, ask students to name an important molecule in

the cell that requires the element phosphorus. If not mentioned, you can explain that the most important energy molecule in the cell is adenosine triphosphate (ATP) and it includes the element phosphorus.

  1. Ask:

“Do you think that humans require the same essential elements as plants?” (Responses will vary. Some students may think that since humans and plants are very different from each other, they will need different sets of elements. Others may reason that since plants and humans are each made of cells, the essential elements needed by both will be similar. Still others may think that since all of the food humans consume ultimately begins with plants that the nutrients may be similar or exactly the same.)

  1. Display an image of Master 1.5, Essential Human Nutrients.
  2. Ask students to comment on how similar or dissimilar the pattern of elements is compared with that shown previously for plants.
  3. Students should notice that the two patterns are more alike than different. If using transparencies, you can align and overlap the transparencies of Masters 1.4, Essential Plant Nutrients and 1.5, Essential Human Nutrients to make this point clearer. If using other technology circle the similarities.
  4. Referring to the box of cereal and candy bar nutrition labels, ask students what types of nutrients they think humans need and how different foods can provide those nutrients. Have the students look at the labels on the two boxes to see how they compare. Ask:

 

“Which nutrients from both labels are the same?”

  1. Have students share with another student in their proximity the ingredients listed on the labels.
  2. Have students refer back to the periodic table of elements. Which of the nutrients from the nutrition label can students find on the periodic table?
  3. Which of the nutrients on the labels are also nutrients that plants need?
  4. Ask students to compare some of the common nutrients that plants and humans both need, such as calcium, copper, iron, magnesium, phosphorus, potassium and zinc.
  5. Based on cereal nutrition label, have five students share which of their foods seem to provide the most nutrients for humans and create a visual list.
  6. Summarize the concept that nutrients plants require to grow are the same nutrients humans need to grow; humans receive these nutrients from plants.

 

Evaluation Options:

  1. Assess student completion and accuracy of Sources of Essential Nutrients.
  2. Evaluate student participation in discussion and activities.
  3. Have students select one of the nutrients discussed that is essential to both humans and plants, research the nutrient and write how the nutrient is used in plants and in humans, what deficiencies are and sources for both plants and humans.
  4. Have students research nutrients that cycle and create a diagram of that cycle (nitrogen, carbon, water).

 

Sample Pre- and Post-Assessment

  1. What is an essential element?
  1. Do plants and animals have the same essential elements? If so name three.
  1. How do plants obtain essential elements