Phototropism Plant Light Maze
Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required
Categories: Plants
Alternative titles: Plant Light Maze
Summary
In this activity, students investigate phototropism - the ability of plants to grow toward light, by designing a shoebox maze with obstacles. A sprouting bean plant is placed inside, and students observe whether it can bend and grow around barriers to reach a light source. This experiment demonstrates how plants use light for photosynthesis and adapt their growth to their environment.
Procedure
*Growing the plant*
- Fill a small container (7–10 cm high) with potting mix, leaving about 1 cm at the top.
- Plant 2–3 pole bean seeds about 2 cm deep.
- Water daily or as needed, keeping the soil moist.
- Place the container under grow lights or in a sunny window until sprouts reach 5–10 cm tall (3–7 days).
*Building the maze*
- Tape any gaps in a shoebox so no light enters except through one hole.
- Cut a square hole (8–10 cm) at one short end of the shoebox for light to enter.
- Divide the length of the box into thirds. At the one-third mark, tape a cardboard barrier to the left side, reaching the box’s height. At the two-thirds mark, tape a second barrier on the right side. This creates a zig-zag path to the exit hole.
- Place the sprout at the opposite end of the hole inside the box.
- Close the lid and secure it with tape.
- Put the shoebox so that the light hole faces a sunny window.
Links
Make Your Own Fun Light Maze For Plants - We Are BLOOM!:
Light Mazes for Plants! - OklahomaGardening:
📄 Plant Light Shoebox Maze Experiment - Little Green Thumbs: https://www.littlegreenthumbs.org/wp-content/uploads/2020/05/Plant-Light-maze.pdf
Variations
- Make larger or more complex mazes to test the limits of phototropism.
- Try different seeds (e.g., sunflowers, peas) to compare species’ responses.
- Change the light source’s position (top, side, angled) to see how growth direction changes.
- Compare growth in a maze with plants grown in full light.
Safety Precautions
- Use scissors safely when cutting the shoebox and cardboard.
- Handle soil and seeds with clean hands, and wash hands after gardening activities.
- Ensure water does not leak from the container inside the shoebox.
Questions to Consider
- Will the sprout grow with minimal light?
- Why do plants need to move toward light in nature?
- What happens if the light is blocked completely?
- How might phototropism help plants compete with neighbors in the wild?
- What other environmental factors (water, nutrients, space) influence plant growth along with light?