Biology: Chemical Reactions -soil analysis

The Science of Looking for Life on Other Planets

Astrobiology is the science of asking whether or not life exists on other planets. Currently, there is not proof that life exists beyond Earth. What we know about life comes from studying Earth.  It is important to study the life that exists on Earth to be able to know where and how to look for life off the Earth.

Mars rovers such as Curiosity and Perseverance (predicted launch date 2020) take soil samples and analyze them.  They then send the information back to scientists on Earth. One thing they look for is organics. Learn more about the search for life on Mars by watching: Why is Curiosity Looking for Organics?

Meet a robotic engineer, Diana Trujillo, working with Perseverance in the search for life on Mars in Behind the Spacecraft – Perseverance Mars Rover


Chemical Reactions

One test that the rovers and scientist do is look for chemical reactions.  This can indicate the presence of organics or the chemicals that make up living things such as Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus and Sulfur. 

Chemical reactions occur when atoms move and one molecule changes to another.  Chemical bonds are either created or broken to create a new molecule.  Signs of chemical reactions include:

  • Changes in color
  • Change in temperature
  • Production of gas (bubbling, fumes or a change in smell)
  • Formation of a precipitate which is a formation of a solid where there was only liquid before.
  • Light production

Let’s test the soil in your Backyard!  Go to the Easy Soil Test  page for your materials and instructions. 


To get credit for this activity, create a Popplet with the following information:

  • Include a photo of you and your soil experiments.
  • Submit your soil results detailing any chemical reactions you saw.
  • As an astrobiologist, what are you going to look for on other planets to see if they contain life?