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Alkaline-Earth Metals
Alkaline-Earth Metals
Grade level: 6-8 Subject: Physical Science Duration: Two class periods
 


lesson plan support
Objectives
Students will
  • Review the importance of the alkaline-earth metal calcium for bones.
  • Research other minerals essential for human health.
  • Create a healthy daily menu that includes at least five minerals.
Materials
  • Alkaline-Earth Metalsvideo
  • Periodic table
  • Print and online resources about minerals needed for human health
  • Computer with Internet access
Procedures
  1. After watching the video, ask students to identify the alkaline-earth metals on a periodic table. What elements are found in this group? (Beryllium, Magnesium, Calcium, Strontium, Barium, Radium) What do these elements have in common? (They all have two electrons in their outer electron shell.)Which of these elements is essential for healthy teeth and bones? (Calcium)
  2. Remind students that our bones are a mix of calcium and other minerals. In fact, 90 percent of the calcium in our bodies is in our bones. Calcium also helps regulate our heartbeat and clot our blood. Ask students to name foods that are good sources of calcium. (Dairy products such as milk, yogurt, cheese, and green leafy vegetables such as spinach, collard greens.)
  3. Explain that calcium is just one of many minerals that are important to human health. A mineral is a natural substance that helps the body function. Like calcium, many minerals are metals. Show students a Mineral Chart like the one below, listing several important minerals. You may want to create this on a bulletin board, as students will be adding to it later.
    Mineral Chart
    Mineral Name Importance to Health Good Sources Type of Element
    Calcium Helps form healthy bones and teeth, helps blood clotting, regulates heartbeat Dairy products (milk, yogurt, cheese), green leafy vegetables (spinach, collard greens) Alkaline-Earth Metal
    Calcium      
    Chlorine      
    Copper      
    Fluorine      
    Iodine      
    Iron      
    Magnesium      
    Phosphorous      
    Potassium      
    Sodium      
    Zinc      
  4. Divide the class into 10 groups and assign them one of the minerals above (besides calcium). Their assignment is to find out the following:
    • Why the mineral is important for human health.
    • What foods are good sources of that mineral.
    • What type of element the mineral is (metal, metalloid, nonmetal; if metal, identify as alkali metal, alkaline-earth metal, transition metal, or other)
  5. At the end of the first class period, have one member of each group to fill in the information on the Mineral Chart for their mineral.
  6. The next day, have students work individually to use the chart and create a healthy daily menu that includes at least five minerals on the chart. Have students write their menu on a piece of a paper, organized into breakfast, lunch, snacks, and dinner.
  7. Have students hang their menus around the Mineral Chart. End with a class discussion about some favorite and unusual foods that provide essential minerals.

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Evaluation
Use the following three-point rubric to evaluate students' work during this lesson.
  • Three points: Students were active in class discussions; correctly identified the mineral's importance to human health, good sources of the mineral, and the type of element; developed a complete, varied daily diet with at least five minerals.
  • Two points: Students participated in class discussions; correctly identified the mineral's importance to human health, good sources of the mineral, and the type of element; developed a complete daily diet with four or five minerals.
  • One point: Students did not participate in class discussions; did not identify the mineral's importance to human health, good sources of the mineral, and the type of element; developed an incomplete complete daily diet with three or fewer minerals.

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Vocabulary
alkaline-earth metal
Definition: a metallic element belonging to group 2 of the periodic table, including: beryllium, magnesium, calcium, strontium, barium, and radium
Context: The alkaline-earth metals are generally softer than most other metals and they react readily with water, particularly when heated.

calcium
Definition: A soft silvery-white element that is an alkaline-earth metal; never occurs freely in nature and easily forms compounds with oxygen and water.
Context: Calcium is an important part of our diets, helping build and repair the bones in our bodies.

compound
Definition: A substance made up of atoms of two or more elements; atoms are bound together in a molecule and can only be separated by a chemical reaction.
Context: Calcium carbonate is a carbon compound used to make white paint, cleansing powder, toothpaste, and stomach antacids.

element
Definition: A substance that is composed of one type of atom; an element cannot be chemically separated.
Context: Calcium is an essential element for countless living organisms.

mineral
Definition: A pure, solid substance that occurs in nature; every mineral has distinct characteristics and a unique chemical makeup.
Context: Our bones are a hard mix of calcium and other minerals on the outside, but they are spongy on the inside.

valence electrons
Definition: The electrons in an atoms outermost electron shell that dictate how elements interact.
Context: Each alkaline-earth metal has two valence electrons in its outermost electron shell.

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Academic Standards

Mid-continent Research for Education and Learning (McREL)
McREL's Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education addresses 14 content areas. To view the standards and benchmarks, visithttp://www.mcrel.org/compendium/browse.asp.
This lesson plan addresses the following national standards:

  • Science-Physical Sciences: Understands the structure and properties of matter
  • Health-Understands essential concepts about nutrition and diet

National Academy of Sciences
The National Academy of Sciences provides guidelines for teaching science in grades K-12 to promote scientific literacy. To view the standards, visit this Web site:
http://books.nap.edu/html/nses/html/overview.html#content.
This lesson plan addresses the following national standards:

  • Physical Science
  • Life Science
  • Science as Inquiry
  • Science and Technology

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