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Cool Science Project: Effects of Overcrowding in a Plant Population

written by: J.Sace • edited by: Wendy Finn • updated: 2/14/2012

In this science project, students will observe how the growth of plants is affected by overcrowding. Students will relate their observations in human populations. This science project is recommended for grade level 6-8.

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    Overcrowding refers to a situation wherein organisms occupy a limited space. Overcrowding has negative effects on the conditions of organisms if food, water, and other resources are limited. The effects of overcrowding are apparent in human populations living in cities. People in overcrowded cities experience scarcity of resources such as land, potable water, food, and fuel.

    It is important that students learn the effects of overcrowding so that they would know how to put value to our resources. They should learn that is not right to waste food, water, and electricity because they are not limitless and we are many to share them. As future managers of our environment, students should learn as early as now that overcrowding is a serious problem of our society and should not be taken for granted.

    The effects of overcrowding can be demonstrated through a dense plant population. Below is the plan of a science project investigating the effects of overcrowding in a plant population grown in pots. The teacher should instruct the students that each of them will perform the project at their homes and they are required to submit written reports about their observations.

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    Materials Needed for the Science Project

    • 2 6-inch plastic pots
    • nail
    • pie pan
    • measuring cup or beaker
    • metric ruler
    • marker
    • tap water
    • radish seeds

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    Procedure for the Science Project

    • Use the nail to create 3 small holes into the bottom of each plastic pot.
    • Mark the 2 pots with the letters “A" and “B" using the marker.
    • Fill each pot ¾ full of garden soil. Do not pack in the garden soil.
    • Plant 5 radish seeds 1 cm apart in pot A. In pot B, plant 20 radish seeds ½ cm apart.
    • Put the 2 pots in the pie pan. The pie pan collects excess water every time you water the plants. Place the pots in a place with sunlight.
    • Water the plants every 3-4 days. The two pots should be given equal amounts of water. Use a measuring cup or beaker to measure water. You should make sure that the soil is damp but not soaked.
    • After a week, measure the height of each plant in pot A and pot B using the metric ruler. Record all your measurements. You can create a chart to organize your data.
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    Questions for Students to Answer

    The teacher will instruct the students to answer the following questions in their written reports. She may add more to these questions if necessary.

    1. Which pot has taller plants?
    2. Which pot has more crowded plants?
    3. Which pot has thicker plant stems?
    4. Which pot has larger plant leaves?
    5. What can you observe on the way the plants grow in both pots?
    6. What will happen to the soil when the plants become too dense?
    7. What problems might happen when a human population became overcrowded?
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    Additional Notes for Teacher

    The teacher will give a lecture class discussing the effects of overcrowding in organisms. Using biological or ecological principles available in the scientific literature, the teacher will explain why overcrowding has detrimental effects to organisms.