Exploring the Nitrogen Cycle

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Objective

SWBAT develop a model to describe the cycling of nitrogen among living and nonliving parts of an ecosystem.

Big Idea

Students explore the nitrogen cycle through various activities.

Engage

10 minutes

To engage students in the lesson I show the TEDEd video The Haber Process by Daniel D.Dulek.  

How do we grow crops quickly enough to feed the Earth's billions? It’s called the Haber process, which turns the nitrogen in the air into ammonia, easily converted in soil to the nitrate plants need to survive. Though it has increased food supply worldwide, the Haber process has also taken an unforeseen toll on the environment. Daniel D. Dulek delves into the chemistry and consequences.

The Haber process is an application of the nitrogen cycle for the benefit of man, since its credited with the production of synthetic nitrogen fertilizer which is responsible for the feeding a third to half the present world population. In fact, about half the nitrogen in each of our bodies is there thanks to the Haber Process. (MS-LS2-3. Develop a model to describe the cycling of matter and flow of energy/matter among living and nonliving parts of an ecosystem.)  

 As students watch video they answer the following questions:

1.  Which gas is the most abundant in our atmosphere?

a.  Oxygen

b. Nitrogen

c. Carbon Dioxide

d. Hydrogen

2.  What type of bond holds together nitrogen atoms?

a. Single Bond

b. Double Bond

c. Triple Bond

d. No bonds hold nitrogen together

3. Which element is most important for growing crops?

a. carbon dioxide

b. hydrogen

c. calcium

d. nitrogen

3. Who discovered how to manipulate equilibrium systems? 

a. Fritz Haber

b. Albert Einstein

c. Stephan Hawking

d. Henry Le Chatelier

Explore

25 minutes

In this section of the lesson students explore the nitrogen cycle by participating in The Nitrogen Cycle Game. (This activity was developed by Lisa Gardiner of the UCAR Center for Science Education for NESTA.)

Introduction

Students play the role of nitrogen atoms traveling through the nitrogen cycle to gain understanding of the varied pathways through the cycle and the relevance of nitrogen to living things.(SP2 - Developing and Using Models/CCC - Energy and Matter - The transfer of matter can be tracked as matter flows through a natural system.)

Student Learning Objectives

  • Students understand that nitrogen cycles indefinitely through the Earth system
  • Students understand the places that it is found on Earth
  • Students understand that nitrogen is essential for life
  • Students learn that the cycle is nonlinear traveling between living things and the physical environment.

Materials

Preparation and Directions are found Nitrogen Cycle Game page.

Explain

10 minutes

In this section of lesson I show students The Nitrogen Cycle online simulation from PBS Learning Media.

  1. What is the largest source of nitrogen on Earth? How does this nitrogen enter the food web?
  2. What kind of relationship exists between nitrogen-fixing bacteria and the plants whose roots they live around?
  3. What is assimilation? Describe the "loop" in the Nitrogen Cycle that involves assimilation by animals?
  4. At what step in the Nitrogen Cycle does bacteria assimilate nitrogen?

Elaborate

10 minutes

In this section of the lesson students read an article titled The Nitrogen Cycle from cK-12.  

Prior to reading students complete a Pre Read activity.  

Objective

To enhance understanding of unfamiliar terms by deconstructing them into their various parts using the Word Parts strategy.

Instruction

Have the students deconstruct the key terms from the concept to identify word parts as the prefix, root, and/or suffix. Instruct them to write each word part in the table below then include the meaning of the prefix, root and suffix along with a definition of word based on the three parts. Students share their definitions with a small group and/or class. While reading the concepts students revise their definition if necessary.  

The article discusses the following topics:

  • Nitrogen Cycle
  • Nitrogen Fixation
  • denitrification

Once students have read article they answer the following text-dependent questions (RST.6-8.1-Cite specific textual evidence to support analysis of science and technical texts):

  1. How do living organisms use nitrogen?
  2. What is nitrogen fixation? Describe how it happens.
  3. How is nitrate in the soil converted back to nitrogen gas?
  4. How does acid rain form?

In addition to the article, I show the The Nitrogen Cycle video, which addresses the needs of both my visual and EL learners.

 

As students watch video they answer the following questions:

  1. What metabolic processes do organisms use nitrogen (N) for?
  2. What sorts of molecules are made using nitrogen?

Evaluate

5 minutes

In this section of the lesson students are given two choices for assessment of their learning.

Option 1

  • Students write about their trip through the cycle including (1) where they went, and (2) how they got there. (Nitrogen Cycle Game)
  • Show students a diagram of the nitrogen cycle. Ask them to create a diagram documenting only their journey.(MS-LS2-3. Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.)  

Option 2

  • Which step in the nitrogen cycle would you say is the most important? Would there be a way to continue the nitrogen cycle if that step couldn't happen? 

Giving students choice in terms of assessment in my experience increases completion rate since they are making the choice of what assessment to complete versus teacher directed.