Activity 1: Selecting Foods

Objective

To select foods that would be potential candidates for cultivation in Martian greenhouses. Although good taste and storage are not the only criteria for selecting food crops on Mars, these will be the selection criteria for this activity. Additional criteria include the ability to be stored easy, utilization of a small amount of space for growing, quick maturation, and the ability to grow successfully in a greenhouse where the effects of sunshine are weaker than on Earth

Fresh Food Preferences

It is generally understood that fresh fruits and vegetables do not usually store well for more than a few weeks, although there are specific fruits and vegetables that seem to store quite well for a few months.

Use the chart Storage Times of Various Crops in the Resources section. Review the chart, familiarizing students with the various food crops and then have them divide the foods into two major groups - those that have short storage lives and those that have long(er) storage lives. In order to make this decision, students will need to determine a collective definition of the terms “short storage lives” and “long storage lives”. Students fill in Column C in preparation for setting up either a collective class journal or personal journals.
Students should then set up the class or personal journals with one entry for Long Storage Life Foods and one for Short Storage life Foods. See Figure 2 below.
Starting with the Long Storage Life Foods and then moving on to the Short Storage Life Foods evaluate the class preference for each individual food using a "show of hands" to vote. For each food in the list decide how many students fall into each group, using the food evaluation scale below. Record the class preferences in the class or individual student journals you set up earlier.

Food Evaluation Scale

"Love It"	"Like It"	"It's OK"	"No Thanks"	"Ugh!"
"Can't get enough of it!"	"Like it most of the time."	"I can take it or leave it."	"Not my preference."	"Not even if I’m starving to death"
Four (4) points per vote.	Three (3) points per vote.	Two (2) points per vote.	One (1) point per vote.	Zero (0) points per vote.

Sample Journal Set-up

Journal sample

Figure 2: A typical journal set-up in which to record the class's food preferences

Analysis

Foods with the lowest final scores are the most disliked by the class and foods with the highest final score are the best loved foods.
On average, which group of foods seems to be preferred - foods that have long storage lives or foods that have short storage lives?
Based on your conclusions in the above question, suggest reasons for the result?

Extension

Using the chart Characteristics of Various Crops in the Resources section, rank order the foods based on energy content per kilogram. Are there any patterns which emerge? (The unit of energy is the joule which has the abbreviation J, and MJ means megajoule or million-joules. For example 3MJ means 3 million joules and 3MJ/kg means 3 million joules of energy per kilogram.)
Consider the options that the first astronauts will have when planting their first crops on Mars. Which crops would you recommend? Consider a variety of criteria upon which to make your recommendations – time to mature, energy content, etc. Develop a chart to illustrate how you would use the space available in the greenhouse (use percentages). Explain your choices in a written format.

Tomatosphere is sponsored by Agriculture and Agri-Food Canada, the Canadian Space Agency, Heinz Canada Ltd, HeinzSeed, Ontario Centres of Excellence, Stokes Seeds and the University of Guelph.