RESULTS
CSI-02 consisted of 4 unique experiments, including the “Silicate Garden.” Osmotic silicate
gardens grow when a solid of a metal-ion salt is placed into a sodium silicate solution. As the
salt begins to dissolve into the silicate, it develops a colloidal semi-permeable membrane of
metal silicate. This investigation examined the growth of several types of silicate gardens when
gravity forces were removed. Four sodium silicates—calcium chloride (CaCl 2 ), magnesium
chloride (MnCl 2 ), cobalt chloride (CoCl 2 ), and nickel sulfate (NiSO4)—were mixed at various
concentrations for study aboard ISS and compared to those grown on Earth using identical sets
of reaction chambers. The reaction chambers were positioned in the Commercial Generic
Bioprocessing Apparatus (CGBA) to capture still and video images of the experiment for
downlink to the control center. In the ground samples, the tubes grew upward regardless of the
location of the semi-permeable membrane’s initial burst, whereas flight experiments exhibited
tubes that grew randomly in all directions (Cartwright 2011). This investigation reached 500
elementary, 3 500 secondary, 5 undergraduate, and 5 graduate students including 30 schools
and 40 teachers.
PUBLICATION(S)
Cartwright JHE, Escribano B, Sainz-Diaz C, Stodieck LS. Chemical-garden formation, morphology,
and composition. II. Chemical gardens in microgravity. Langmuir. 2011;27(7):3294-3300. doi:
10.1021/la104193q.
These investigations are complete and all results are published.