Food Science Fair Project
Does the "5 Second Rule", of picking up a piece of food from the floor, work?

Projects by Grade Level
1st 2nd 3rd 4th 5th 6th
7th 8th 9th 10th 11th 12th
Home Advanced Award Winning Warning!
Project Information
Title: Find out if the "Five Second Rule" of picking up a piece of food that has dropped on the floor within 5 second eliminates the possibility of germs on that piece of food.
Subject: Food Science
Grade level: Elementary School - Grades 4-6
Academic Level: Ordinary
Project Type: Experimental
Cost: Low
Awards: 2nd place, Canada Wide Virtual Science Fair ($25)
Affiliation: Canada Wide Virtual Science Fair (VSF)
Year: 2012
Equipment, Materials and Techniques: cotton swabs, bananas, stopwatch, agar gel in petri dishes, general lab equipment and safety
Description: Pieces of food are dropped on the floor for different time periods and the food samples are placed in Petri dishes to test for bacteria.
Five-second rule as presented in a WikiWorld comic
GNU 1.2; CC 3.0

A common superstition, the five-second rule states that food dropped on the ground will not be contaminated with bacteria if it is picked up within five seconds of being dropped. Some may earnestly believe this assertion, whereas other people employ the rule as a polite social fiction that will allow them to still eat a lightly-contaminated piece of food, despite the potential reservations of their peers.

There are many variations on the rule. Sometimes the time limit is modified. In some variations, the person picking up the food arbitrarily extends the time limit based on the actual amount of time required to retrieve the food. In Russia there exists a similar rule: "Promptly picked up is not considered fallen".

The five-second rule has received some scholarly attention and has been studied as both a public health recommendation and as a sociological effect.

In 2003, intern Jillian Clarke of the University of Illinois at Urbana–Champaign found in a survey that 56% of the men and 70% of the women surveyed were familiar with the five-second rule. She also determined that a variety of foods were significantly contaminated by even brief exposure to a tile inoculated with E. coli. On the other hand, Clarke found no significant evidence of contamination on public flooring. Clarke received the 2004 Ig Nobel Prize in public health for this work.

A more thorough study in 2006 using salmonella on wood, tiles, and nylon carpet found that the bacteria were still thriving after twenty-eight days of exposure under dry conditions. Tested after eight hours' exposure, the bacteria could still contaminate bread and bologna in under five seconds, but a minute-long contact increased contamination about tenfold (with tile and carpet surfaces only). The five-second rule was also featured in an episode of the Discovery Channel series MythBusters. There was no significant difference in the number of bacteria collected from 2 seconds exposure as there was from 6 seconds exposure. The moisture, surface geometry and the location the food item was dropped on did, however, affect the number of bacteria.

Ted Allen put the rule to the test in an episode of Food Detectives, and found that bacteria will cling to food immediately. High traffic areas will lead to even more bacteria on the food.

As a popular superstition, the five-second rule pops up frequently in popular culture, including appearances in the live-action/animated film Osmosis Jones, Grey's Anatomy, The Late Late Show with Craig Ferguson, Arthur, Bucket & Skinner's Epic Adventures and The Simpsons.

See also:

Source: Wikipedia (All text is available under the terms of the Creative Commons Attribution-ShareAlike License)

Useful Links
Science Fair Projects Resources
Citation Guides, Style Manuals, Reference
General Safety Resources
Electrical Safety FAQ
Food Science Fair Projects

Food Science Experiments


Projects Home
Primary School
Elementary School
Middle School
High School
Easy Projects
Award Winning
Popular Ideas
Branches of Science

Science Fair Project Guide
Science Fair Project Types
The Scientific Method - How to Experiment
The Display Board
Topics, Ideas, Sample Projects

Repeat Famous Experiments and Inventions
Science Jokes Science Trivia
Scientists & Inventors

Read for Free
The Science Fair
A Juvenile Science Adventure Novel
by Julian T. Rubin

Human Abridged Wikipedia Articles

My Dog Kelly

Follow Us On:

Privacy Policy - Site Map - About Us - Letters to the Editor

Comments and inquiries:

Last updated: February 2019
Copyright © 2003-2019 Julian Rubin