SeedSpinner: Simulating microG with littleBits and FastPlants

by MWMathSci

Published on April 23, 2014

Based on original research in Michael Wilkinson's 4th Grade Science Classroom at Fieldston Lower School ECFS (,

littleBits in the elementary science lab facilitates a STEAM process that enables students to easily design, build and engineer prototypes of lab apparatus that would otherwise be inaccessible. The following project is an illustration of how littleBits can be used to support serious scientific inquiry.

Authentic scientific exploration often relies on engineering apparatus to facilitate obtaining the data that supports or contradicts a hypothesis.

ENGINEERING CHALLENGE: How can littleBits be combined with other materials to build an apparatus and prove that the direction in which a seedling's roots grow is affected by gravity?

OBJECTIVE: Students will engineer a littleBits lab apparatus to negate the effect of gravity on plant seedlings.

PROJECT: The design shown here is our solution to this challenge. For full lesson instruction, see

Guiding Question for Students: How can we prove that the direction in which a seedling's roots grow is affected by gravity?

What is Microgravity? Microgravity (microG) is a state in which the effects of gravity have been cancelled out; this state is sometimes referred to as zeroG, however, this is a misnomer. Microgravity is experienced by astronauts as they orbit the earth in the International Space Station. Microgravity is perceived by a sense of weightlessness, which is created by "free-fall."

To learn more about microgravity, check out the following links:

NASA - What is Microgravity? 

DragonflyTV (PBS Kids) Earth & Space - Microgravity

NASA SPACElife Science - Plants in Space

NASA Educator Guide to Microgravity 

Note: FastPlants are a special hybrid of Brassica rapa - the same species that fill our dinner plates as broccoli, cauliflower, Brussels sprouts, collards and many others (FastPlants are distributed by Carolina Biological).

How To Make It

STEP 1 :

Seed Preparation: Glue 4 seeds in a square pattern centered on each filter paper circle. Seeds should be 2-3cm apart. Use toothpick to transfer a small drop of white glue to the position for each seed.

STEP 2 :

Use hand lens to identify the position of the seed scar. Orient the seeds each pointing a different direction: up, down, left, right. With a pencil, indicate seed orientation with a small arrow near the seed.

STEP 3 :

Label the filter paper circle with the lab group, date, and trial: light (control), dark (experimental) or spin/microgravity (experimental).

STEP 4 :

Allow glue to completely dry. (Note: this step can be completed several days before initiating the lab)

STEP 5 :

Construct Germination Chamber: Each lab group will need three germination chambers. One each for the light (control), dark (experimental), and spin/microgravity (experimental). The light trial and dark trial chambers require only a Petri dish with no further modification.

STEP 6 :

Spin/Microgravity Chamber: Use a punch awl or nail to make a small hole (3mm) in center of plastic bottle cap. This is how the chamber will be mounted to the motor and needs to be a tight fit. The optional "motor mate" from littleBits could also be used. In which case, the hole in the bottle cap would need to be larger.

STEP 7 :

Use superglue to attach the bottle cap to the Petri dish. Run a thin bead of glue on the edge of the cap, then hold it firmly against the center of lid of the Petri dish until the bond has cured. The lid of the Petri dish is the shallow side with the larger diameter of the two pieces.

STEP 8 :

Construct Circuit: Power + Pulse + Wire + DC motor

STEP 9 :

Build Motor Support: Use snap cubes to build base that will place motor armature extending over the side of the reservoir and 5-6cm above the base of the reservoir.

STEP 10 :

Secure motor Bit to support with rubber bands.

STEP 11 :

Attach Petri dish to the motor armature, gently pressing the armature into the hole. Adjust Petri dish angle as needed to achieve as uniformly vertical orientation as possible.

STEP 12 :

Place filter paper circle with seeds in the lids of the Petri dishes.

STEP 13 :

The base of the Petri dish on the spin/microgravity trial chamber will need to be secured to the lid with strips of masking tape.

STEP 14 :

Cut strips of masking tape about 5cm long by 0.5cm wide.

STEP 15 :

Use the tape strips to secure the base of the Petri dish to the lid.

STEP 16 :

Test SeedSpinner prototype and make any necessary adjustments.

STEP 17 :

Place the SeedSpinner near the container to be used as a water reservoir. The Petri dish should dip into the water no more than 1cm, just enough so as to wick the water onto the filter paper and ensure constant moisture to the seeds.

STEP 18 :

Add water to the reservoirs.

STEP 19 :

Place the light (control) trial chambers in their reservoir under a bright fluorescent bulb or in direct sunlight.

STEP 20 :

Place the dark (experimental) trial chambers in their reservoir under a dark bucket or box or in a dark cupboard to shield from the light.

STEP 21 :

Place a dark bucket or box over the assembled SeedSpinner to shield seeds from the light.

STEP 22 :

SeedSpinner should run continuously for 5 days. Check daily to ensure proper movement and water level is maintained.

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