Soap vs. Sanitizer

Laboratory Experiment

Why wash your hands? Hand are the most

frequent transmission route for many types of infections.

Pathogens may enter through the mouth, nose, or eyes.

Proper hand hygiene is the easiest way to reduce infections.

How do you wash properly? Scrub your hands with

soap and warm water for 20 seconds to 2 minutes.

Scrubbing your hands physically removes dirt and grease, which wash away with the water

What about hand sanitizer? When water is not available, hand sanitizer

can be an effective alternative. The alcohol in hand sanitizer disrupts the

coating on bacteria and viruses. Use enough sanitizer to keep your hands

wet while you rub for at least 30 seconds.

Soap vs. Sanitizer Experiment Problem/Question:

Which is more effective at reducing the amount of bacteria on hands: washing with soap or antibacterial sanitizer?

Hypothesis & Prediction: If washing with soap and water is more effective at

reducing the amount of bacteria on hands, then the soap treatment will show a greater reduction in bacterial growth than the sanitizer treatment.

Experimental Design Independent/Manipulated Variable:

Cleanser/Chemical Dependent/Responding Variable:

Bacterial growth Treatments:

Soap Sanitizer

Control: No soap or sanitizer

Analysis: Compare percent reduction in bacterial

growth

Methods Label your Petri dish

Group #Treatment Before/After

Before After

Gro

up

1

Contro

l

Methods How to sample:

Methods Apply treatment for 30 seconds

Analysis # Before - # After = Difference Difference ÷ # Before = Reduction Reduction x 100 = % Reduction

TREATMENT

Number of Bacterial Colonies

Before After Difference%

ReductionControl 1

Control 2

Control Average:

Soap 1

Soap 2

Soap Average:

Sanitizer 1

Sanitizer 2

Sanitizer Average:

Analysis Sample results:

TREATMENT

Number of Bacterial Colonies

Before After Difference%

Reduction

Control 1 119 500 -381 -320%

Control 2 198 32 166 83.8%

Control Average: -118%

Soap 1 100 68 32 32%

Soap 2 6 90 -84 -1400%

Soap Average: -684%

Sanitizer 1 7 1 6 85.7%

Sanitizer 2 23 2 21 91.3%

Sanitizer Average: 88.5%

Expected ≈ 0

Expected > 0