Environmental Pollution: The effect of carbon dioxide on plant growthFeatured science projectScience project video

popular science fair projects
Complexity level:
7
Project cost ($):
Time required:
Approximately 1 hour to complete initial set-up, with 15 to 30 minutes daily observation and discussion for five days.
Material availability:
Safety concerns:

Abstract

Global warming occurs when greenhouse gases in the planetís atmosphere trap and retain heat, altering the earthís climate. Plants are affected by higher greenhouse gas levels, even though they consume carbon dioxide and sunlight to make energy. This science project encourages students to compare the growth of a plant under natural conditions with a plant that has been exposed to extra carbon dioxide.

Hypothesis

Based on the description of photosynthesis above, do you think a plant surrounded by more carbon dioxide will grow faster or slower?

Objective

To connect carbon dioxide emissions to plant growth and global warming / pollution.

Background

Plants process carbon dioxide (CO2) into energy using photosynthesis. Humans and other animals expel carbon dioxide when we breathe out. The oxygen we breathe to sustain life largely comes from plants' photosynthesis process, which turns toxic carbon dioxide into breathable air for humans.

Oxygen is not the only product created during photosynthesis. Plants get their energy from carbon dioxide because they convert it into sugar, which they use for food. Plants love to "eat" the sugar, which allows them to grow larger because it gives them energy for growth.

The sun's energy is required for photosynthesis.

Global warming occurs when greenhouse gases such as carbon dioxide absorb extra heat from the atmosphere, raising the ambient temperature. Global warming is thought to be caused by humans' use of fossil fuels, including burning coal and using gasoline in our cars. Water vapor also traps heat in the atmosphere. In this system, we will create a replica of an atmosphere using two-liter bottles. We will examine whether plants grow faster in the carbon dioxide-rich environment or the normal environment.

We will make our own carbon dioxide by combining baking soda and vinegar, which gives off CO2 gas.

Scientific Terms

Carbon dioxideOxygenPhotosynthesisSugarGlobal warmingGreenhouse gasesFossil fuelsWater vapor

Materials

  • 1 small bag of potting soil
  • 2 two-liter soda bottles with the tops cut off
  • 4 peat cups with seeds already germinated (just sprouted) in peat cups
  • 2 shallow dishes or paper cups cut in half
  • 30 g baking soda
  • 60 mL white vinegar
  • Scale
  • Graduated cylinder
  • Thermometer
  • Ruler

Procedure

  1. Find a place where your experiment can sit for the week.
  2. Check the seeds to make sure they have partially sprouted. Set them aside.
  3. Make a control experiment by putting one seedling underneath an upside-down soda bottle. Also include a thermometer.
    sprouting seedlings for carbon dioxide plant experiment
  4. Set the control aside. Now, get ready to make the experimental system.
  5. Measure 15 g of baking soda into the shallow dish or paper cup.
  6. Measure 30 mL white vinegar in your graduated cylinder.
  7. Slowly add the vinegar to the cup with the baking soda.
  8. Carefully place one peat cup and the cup with the vinegar mixture under the soda bottle. Put the thermometer underneath, as well.CO2 science project experiment setup
  9. Wait 20 minutes, and record your observations in ďDay 1Ē of the observation table below. Do this for both the control and the experimental systems.
  10. Make sure to measure the plantís height with your ruler. Do this on the outside of the bottle, as we do not want to disrupt the system.
  11. Record data on your chart every day.
  12. On the fifth day, graph both plantís growth on axes comparing time and height.

 

Observations

EXPERIMENT plant with vinegar mixture

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

Day 7

Can you see water vapor / droplets? Yes or no.

             

Temperature

             

Plant size in cm

             

CONTROL plant without vinegar mixture

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

Day 7

Can you see water vapor / droplets? Yes or no.

             

Temperature

             

Plant size in cm

             

 

Discussion

  1. Which plant grew more during the week? Did this match your expectations?
  2. Explain the difference between the water vapor for both plants between day 1 and day 7.
  3. How did the temperatures change inside the control plant bottle? What about inside the experimental bottle?
  4. Do you think the carbon dioxide helped the plant grow?
  5. Which bottle represented global warming, based on your temperature measurements?

 

Questions & Answers

Where will the CO2 come from in this experiment?

The vinegar and baking soda

How does global warming change the earth's temperature?

By trapping greenhouse gases beneath the atmosphere.

Plants consume ______________ _______________ and give off ___________________.

Carbon dioxide / oxygen

Make it Your Own

Consider adding water in the soda bottle in a shallow dish. Blow into the water with a straw and then quickly cover the entire system (plant, dish and thermometer). Use the same control. Consider why the environment would change by blowing into the water!

References

Hays, J. "How do increased CO2 levels affect plant growth?"

Videos