24. TAKING A BIT OF HOME UP WITH YOU

SUBJECT: Science
GRADE: 7,8,9
GROUP SIZE: Small
TIME: 2-45 minute periods
TYPE OF ACTIVITY: Student Investigation
TEACHING STRATEGY: Expository and Guided Discovery
CONCEPTS: Closed Ecological System Oxygenation
SKILLS: Experimentation Observation Inference

Objective: To reinforce the concept of a “closed ecological system” and relate this concept to life on a spacecraft.

Materials: Three bottles or jars with tight covers; aquarium snails or guppies; aquarium water.
Teacher Background Information: The cabin of a space vehicle must be constructed so that it provides all of the conditions necessary to sustain life. Both the physical and the mental health of those on board must be considered. This experiment deals with the need for oxygen production and the removal of carbon dioxide from the cabin atmosphere.
Procedure:

Fill the three bottles with aquarium water. Into each jar place the following: Jar A – aquarium plants; Jar B – snails or guppies; Jar C – plants and snails or guppies. (Make sure there are enough plants and light for photosynthesis or the organisms will die.) Now, add more aquarium water to each jar so that they overflow slightly. Cap each jar tightly and allow them to stand for a few days.

Observe the jars after two days. Look for any changes and note any differences in behavior of the organisms. Continue this observation and recording for several more days.

Relate each jar to possible conditions in a space vehicle. What provisions were made in each jar for life support? What factor did time play in this experiment? What is meant by the term “closed ecological system”? What provisions would need to be made for astronauts on board the shuttle for a two week stay in space? How does what you must consider for the astronauts relate to the closed system in the jars? How has NASA dealt with these concerns on the Shuttle or in the Skylab?
Teacher Note: You may wish to use this as an introduction to the several activities which follow. The lessons cover environments in space for people and deal with oxygen, food, air pressure, temperature, etc., all necessary components of a closed environment such as a space vehicle.

Adapted from educational materials available from NASA Kennedy Space Center Teacher Resource Room