Second Grade NGSS
Plants, Growth, Pollination

 

Learning about elements and those found in soil.

OBJECTIVES:
  • Exploring elements.
  • Investigating the nutrient cycle of a garden.
 VOCABULARY
     elements
         
decomposers
     nutrient
     organic matter

MATERIALS:
    periodic table plamats
    element specimens
    worksheet
    bag of macronutrients and micronutrients

BACKGROUND:

Nutrients in the soil are important to plants in order to survive.  Nutrients can be complex organic molecules like carbohydrates, fats or protein.  They can also be inorganic like zinc or copper.  However all nutrients are composed of elements in a chemical state that can be used by the organisms.   

In a process called photosynthesis, plants use energy from the sun to change carbon dioxide (CO2 - carbon and oxygen) and water (H2O- hydrogen and oxygen) into starches and sugars. These starches and sugars are the plant's food.  Photosynthesis means "making things with light". Since plants get carbon, hydrogen, and oxygen from the air and water, there is little farmers and gardeners can do to control how much of these nutrients a plant can use.  

The 13 mineral nutrients, which come from the soil, are dissolved in water and absorbed through a plant's roots. There are not always enough of these nutrients in the soil for a plant to grow healthy. This is why many farmers and gardeners use fertilizers to add the nutrients to the soil.  The mineral nutrients are divided into two groups:  macronutrients and micronutrients.   

Macronutrients can be broken into primary and secondary nutrients.  The primary nutrients are nitrogen (N), phosphorus (P), and potassium (K). These major nutrients usually are lacking from the soil first because plants use large amounts for their growth and survival.  The secondary nutrients include calcium (Ca), magnesium (Mg), and sulfur (S). There are usually enough of these nutrients in the soil so fertilization is not always needed. Also, large amounts of Calcium and Magnesium are added when lime is applied to acidic soils. Sulfur is usually found in sufficient amounts from the slow decomposition of soil organic matter, an important reason for not throwing out grass clippings and leaves.  

Micronutrients are those elements essential for plant growth which are needed in only very small (micro) quantities. These elements are sometimes called minor elements or trace elements. The micronutrients are boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo) and zinc (Zn). Recycling organic matter such as grass clippings and tree leaves is an excellent way of providing micronutrients (as well as macronutrients) to growing plants.

Notice that all the components are ultimately composed of chemicals.  However, there are inorganic components that are "given" or specific to an area.  The ecosystem has to build itself on soil (organic matter + rock).   Organic matter is carbon based, but rocks can be made of a variety of chemical compounds which add character to a particular soil. Remember, minerals make-up rocks, and minerals can be composed of elements or compounds. 

PROCEDURE:

1.    Tell the students that today they will be looking at some of the elements found on the Periodic Table. These elements are either found in nature or manufactured.   Hand out the Periodic Table of the Elements Placemat.  Go over things like where is the atomic number and it goes horizontally.   Not all the letters are abbreviations of the English word.  As they look at the samples tell them that they will need to use words to describe them.  

2.    On each table have a sample of   
COPPER - copper color, used to make pipes, teapots, etc (native mineral)
NICKEL
 - gray color, used to make nickels and metal, naturally magnetic
LEAD 
- gray color, used to make metals, flexible, heavy
SILICON 
- white or gray color, used in computer industry to make computer chips
CARBON 
- gray color, used in making pencils, rubs off easily
SULFUR
 - yellow color, used in making medicine, (native mineral)
ALUMINUM 
- gray color, used to make aluminum foil and other metals
IRON 
- gray color, used in the steel industry, and has other uses as a metal
ZINC 
- gray color, used as metal
TIN
 - gray color, shiny, bends, used as a metal

Please note that many of these samples are not what plants require.  The exercise is just for students to investigate the periodic table.
 

3.    Talk about that plants need nutrients to live including the Macronutrients of N, P, K, Ca, Mg, and S .  And micronutrients including B, Cu. Fe, Cl,  Mn, Mo, Zn

4.   
Use the worksheet and find the name and atomic number and write it in the space provided.  Then cut them out and put them on the periodic table

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