Science Fair Project

Does Caffeine affect how fast a plant will grow? If I have 3 of the same plants, and I water one with caffeinated coffee, one with water, and one with decaffeinated coffee, which one will grow the fastest?

Interesting facts Caffeine is found in many plant species where it acts as a natural pesticide. Caffeine is a stimulant drug Caffeine is found in many plants, beans, leaves, and some fruits. Humans have been using caffeine since the Stone Age. In humans caffeine is a central nervous system that temporarily wards off drowsiness and restores alertness. Caffeine is the worlds most widely consumed psychoactive substance One of the worlds primary sources of caffeine is the coffee bean Tea is another common source of caffeine Over the years people have been putting caffeine into things like soap and shampoo Too much caffeine can kill you

Hypothesis If I water a plant with caffeinated coffee, then it will grow faster than a plant watered with decaffeinated coffee, and one watered with water, because I think that the caffeine will increase the rate at which the plant grows.

Materials 3 plants of equal size and type Folgers caffeinated coffee Folgers decaffeinated coffee Water Coffee maker Pitcher Sunlight Ruler Paper Computer/flash drive Log book

Procedure 1) purchase 3 plants of the same type and height 2) label the plants 3) place all 3 plants in sunlight 4) measure with a ruler the beginning height of each plant in my log book 5) record the beginning height of each plant in a log book 6) brew one pot of Folgers caffeinated coffee 7) brew one pot of Folgers decaffeinated coffee 8) fill a pitcher with water 9) water plant #1 with the caffeinated coffee (every 2-3 days) 10) water plant #2 with decaffeinated coffee (every 2-3 days) 11) water plant #3 with water (every 2-3 days) 12)Measure each plants growth after every watering 13) record each plants growth in the log book 14) determine which plant has grown the most 15) check my hypothesis to see if it was correct

Control Variables The same type of plant Same amount of sunlight Same amount of liquids per plant Each plant got watered every 2-3 days Same brand of coffee

Observations The Plant watered with regular water grew the fastest The Plant watered with caffeinated coffee grew the second fastest The plant watered with decaffeinated coffee grew the slowest Although the amount of caffeine given to each plant was different, all three plants had the same color of leaves and soil Although all three plants started out at the same height, they all grew at different rates

Data Plant Number Type of Water Beginning Plant Height 10/30/09 Ending Plant Height 12/03/09 Plant Growth Plant 1 Caffeinated 9 4/16 inch. 10 0/16 inch. 12/16 inch. Plant 2 Decaffeinated 9 13/16 inch. 9/16 inch. Plant 3 Plain water 10 6/16 inch. 1 2/16 inch.

Data Analysis By observing my experiment I noticed that the plant watered with plain water grew the most, the plant watered with caffeinated coffee grew the second most, and the plant watered with decaffeinated coffee grew the least. There was a significant amount of growth differential between the plant watered with plain water, and the plant watered with decaffeinated coffee.

Conclusion My hypothesis was that the plant watered with the caffeinated coffee would grow the fastest. This was incorrect. It was in fact the plant watered with the plain water that grew the fastest, and the plant watered with the caffeinated coffee grew second fastest, and the plant watered with the decaffeinated coffee grew the slowest. I would probably pick a different type of plant for experiment next time because the plants I picked did not grow very fast. This made it harder to tell if the reason why one grew faster than the others was because of the caffeine or not. One new question that I have is, are there other reasons why the plants grew at different rates besides caffeine or no caffeine? Also, are there chemicals in both the caffeinated and decaffeinated coffee that could have slowed down the plants growth compared to the one that was watered only with the plain water? In addition to my other questions I also wondered if there were any errors that I could have made that may have altered the results of my experiment.

References The Naked Scientists Forum MyCaffeineAddiction.com Wikipedia Encyclopedia PlantingScience.org