Editing Life on Mars (section)

== Demonstration ==

'''Preparation: Making the "Martian Soil" Samples:
# Mix the sand and dirt in a large bowl. Add a small amount of red food dye and mix thoroughly to turn the "Martian soil" red. separate the mix into three equal sized piles and set aside to dry.
# Make three piles of sugar, one larger and two smaller. and add yellow food dye to each pile. Mix thoroughly and set them aside to dry.
# Make a small pile of salt and add blue food dye. Mix thoroughly and set aside to dry.
# Once the piles have all dried, separate the salt into two larger piles and one smaller pile. Mix the small salt pile with the large sugar pile and a soil pile, then store and label it as "Sample A". Mix the remaining piles accordingly and label them "Sample B" and "Sample C". 
# Add some yeast to sample A, half as much in Sample B, and none in Sample C. Mix it in, and keep the containers stored in a cool, dry space to avoid accidentally activating the yeast.

;Presentation:
# 10-15 minutes before presenting, fill each test tube halfway with their respective samples. Add enough water into each test tube to cover the soil mixtures, and gently mix them to ensure all the soil is wet. Put a balloon on top of each test tube, and place them inside the beaker. fill the beaker 2/3 with water, and place it on the hot plate set to low-medium heat (2-3). Keep the hot plate off to the side until needed.
# Show the audience the bottles with samples, and explain that the samples are similar to what we might find on the martian surface: They have some soil, some sand, some basic compounds (salt) and some complex compounds (sugar).
# Ask the audience if they know how we might check for past life on Mars. Answers might range from our search for water, to checking for organic compounds, to testing soil samples.
# Expand on the idea of testing soil samples. Explain that one way we are testing the soil samples is similar to how we show that yeast is alive; by gently warming it, adding water, and seeing if anything such as CO<sub>2</sub> comes out to show respiration.
# Pull out the hot plate with the samples. By this point, Sample A should have some CO<sub>2</sub> trapped, while Samples B will be mostly limp and Sample C will have nothing. Explain that the type of soil sample can determine the kind of result we find.