5 Science: Nitrogen

Nitrogen (N) is an essential component of the building block of life similar to DNA.  All organisms require nitrogen to live and grow.  Making it the fourth most abundant element in the universe by mass.


  1. Markers or crayons
  2. 1 Nitrogen Cycle Sheet per student

Screen Shot 2016-09-12 at 8.07.33 PM.png

Screen Shot 2016-09-12 at 8.09.16 PM.png


  1. Explain the above charts to your students.  Since their page is black and white, as you speak about each aspect, ask the students to color in their chart.
    1. Younger students do not have to write out the words.  Explaining some of the terms is fine.
    2. The concept of a cycle is the primary point of this exercise.  Birth, life, death, decay…
    3. Discuss what would happen if there was no decay.  How many trees would be able to grow if there were mountains of dead trees around?  God reuses everything and everything has a purpose.  Even excrement has great value.
  2. After your students have filled in the page, walk outside with them to observe nitrogen in their environment.  This is a NO touch walk.  You’ll want to point out animal excretions, clover, decaying wood, dead bugs and animals, roots…

Processes in the Nitrogen Cycle

  • Fixation – Fixation is the first step in the process of making nitrogen usable by plants. Here bacteria change nitrogen into ammonium.
  • Nitrification – This is the process by which ammonium gets changed into nitrates by bacteria. Nitrates are what the plants can then absorb.
  • Assimilation – This is how plants get nitrogen. They absorb nitrates from the soil into their roots. Then the nitrogen gets used in amino acids, nucleic acids, and chlorophyll.
  • Ammonification – This is part of the decaying process. When a plant or animal dies, decomposers like fungi and bacteria turn the nitrogen back into ammonium so it can reenter the nitrogen cycle.
  • Denitrification – Extra nitrogen in the soil gets put back out into the air. There are special bacteria that perform this task as well.

Why is nitrogen important to life?

Plants and animals could not live without nitrogen. It is an important part of many cells and processes such as amino acids, proteins, and even our DNA. It is also needed to make chlorophyll in plants, which plants use in photosynthesis to make their food and energy.

How have humans altered the nitrogen cycle?

Unfortunately, human activity has altered the cycle. We do this by adding nitrogen into the soil with fertilizer as well as other activities that put more nitrous oxide gas into the atmosphere. This adds in more nitrogen than is needed by normal cycle and upsets the cycle’s balance.

Fun Facts

  • Around 78% of the atmosphere is nitrogen. However, this is mostly not usable by animals and plants.
  • Nitrogen is used in fertilizer to help plants grow faster.
  • Nitrous oxide is a greenhouse gas. Too much of it can also cause acid rain.
  • Nitrogen has no color, odor, or taste.
  • It is used in many explosives.
  • About 3% of your body weight is nitrogen.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s