Activity 1: Selecting Foods

Objective

To select a few foods that would be potential candidates for cultivation in Martian greenhouses. Good taste and storage capacity are the selection criteria used in this activity.

Note: Taste and storage capacity are not the only criteria for selecting crop foods on Mars. On Mars we will need to cultivate foods that store well, taste great, produce the most food in a small amount of space, mature quickly, and can grow successfully in the weak sunshine of Mars.

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.

Using the chart Storage Times of Various Crops in the Resources section that follows, divide the food into two major groups - those that have short storage lives and those that have long(er) storage lives. Note: it is recommended that you discuss the chart first with students, familiarizing them with the crop vocabulary and reviewing strategies for reading a chart. Students can 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!"
"Really love to eat the food - can't get enough of it!"	"Like the food most of the time."	"I can take it or leave it."	"I prefer not to eat it, thanks."	"Couldn't force me to eat it even if I were starving to death!"
Assign four (4) points per vote.	Assign three (3) points per vote.	Assign two (2) points per vote.	Assign one (1) point per vote.	Assign 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, can you suggest reasons for the result?

Extension

Using the chart Characteristics of Various Crops in the Resources section that follows decide whether favourite foods or most-disliked foods have the largest energy content per kilogram. (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.)
Suppose that you were going to design a greenhouse garden and plan the crops that the first astronauts would grow during their long stay on Mars. Which crops would you select? Explain your choices. HINT: It is not good to have all the crops mature at once.

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.