invention

Exploring Light and Plant Pigments 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 (http://www.ecfs.org, http://mwmathsci.blogspot.com)

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 authentic inquiry.

DESIGN CHALLENGE: How can littleBits be combined with other materials to build an apparatus to prove that the color of light will affect the expression of chlorophyll in the leaves.

OBJECTIVE: Students will engineer a littleBits lab apparatus to control the color(s) of light the seedlings are exposed to and test their effect on expression of chlorophyll in plant seedlings.

PROJECT: The design shown here is our solution to this challenge. For full lesson instruction, see http://littlebits.cc/lessons/exploring-light-and-plant-pigments-with-littlebits-and-fastplants-lesson

GUIDING QUESTION: How can we prove that the color of light will affect the amount of chlorophyll produced by seedlings?

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).

The materials listed will support a class of 24 students working in groups of four.

How To Make It

1

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

2

Label the filter paper circle with the lab group, date, and trial: white light (control), dark (control), red (experimental), green (experimental), and blue/violet (experimental).

3

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

4

B. Construct the circuits:
For white light: USB power + wire + branch + 3x bright LED. For red light: USB power + wire + branch + 3x RGB LED. For green light: USB power + wire + branch + 3x LED. For blue/violet light: USB power + wire + branch + 3x RGB LED

5

C. Construct the testing apparatus:
Mount fork and attached LED Bits to the top inside of the cardboard box. Extend the wire Bit outside the box to the power bit. Fork and LED Bits can be affixed to the box with double stick tape or other adhesive. If necessary, use opaque tape to seal any openings to block uncontrolled light from outside the box from leaking in. Power up the circuit and confirm that it functions properly.

6

For the red and blue/violet trials, the RGB led needs to be “tuned” with the littleBits screwdriver to achieve the desired color.

7

D. Construct Germination Chamber:
Each lab group will need 5 germination chambers. One each for white light (control), dark (control), red (experimental), green (experimental), and blue/violet (experimental).

8

Place the filter paper circle with seeds inside the lid of the petri dish.

9

Add 1cm of water to the reservoir.

10

Place one petri dish with seeds from each group into the water reservoir (12 x 12 x 6 cm plastic container).

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E. Final Assembly and Experiment Initiation:
Ideally, the lab apparatus will be placed where there is little or no outside light. Place reservoir of germination chambers under the box.

12

Maintain light color conditions for 5 -7 days.

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Refer to the lesson plan for experiment observation and analysis.

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