Teachers Did an Experiment to Show the Power of Handwashing, and You Won’t Be Able to Stay Unimpressed

Teaching should be done like this... Hats off!!

Okay the question I have is, how was the bread handled when it was put in the bag? The Hand Sanitizer sample looks as if ONE person grabbed it by the edge with unwashed hands, or unsanitary tongs. I have seen doctors interviewed from HUGE hospitals say that hand sanitizer is as good as hand washing and is less drying than soap and water. Another point is that if you over-sanitize everything, nobody builds an immune system. Clean is good and healthy but so is a little dirt and germs.

Did she atually wipe that poor bread with chromebooks????

I'd love to know whether the sanitizer used was alcohol-based (like Purell) or benzalkonium chloride based.

nice

You cannot cultivate bacteria or viruses on bread, only mould. Mould does not cause infections unless you are very, very sick (with a severely suppressed immune system, like terminal stages of AIDS, or before a bone marrow transplant).

Very INTERESTING!!!!

Most schools never clean the student technology. I won’t even pick up a laptops without paper towels!!! They are absolutely disgusting. If the students refuse to plug them in oh well they don’t have computers to use. I’m not going to get sick or worse!!!

Although this simple experiment is fun and a great way to engage young people in scientific thought, it is important to note that there are few, if any conclusions that can be drawn from it. Firstly, hand sanitizers are not all the same! Only those with >90% ethanol content will destroy a significant number of pathogens. Secondly, this experiment attempts to grow pathogens on a bread medium - most bacteria require specific mediums to grow, and viruses will not reproduce without a host. Thus, the simple appearance of mold on bread does not necessary indicate anything about the pathogen reducing abilities of any modality of cleaning hands. Lastly, there are very specific protocols to using both hand sanitizers as well as hand washing, including what type of soap is used. Without knowing these details, it is impossible to say whether one modality was better than another... However, there are dozens if not hundreds of research articles published on this topic showing that hand sanitizers are much more effective at killing a wider range of pathogens than hand washing, but that hand washing is more effective at removing, or washing away pathogens especially when embedded in oils or contamination. Bottom line? Both modalities of hand cleansing are an important part of staying healthy and clean, and should be used in combination. Before anyone asks, yes, I am a doctor with a significant research background.

That’s a nice proxy demonstration for cleanliness, but as Eli and Attila state above what she’s looking at there is fungi and mould, not bacteria. The circular growth form on the hand sanitizer slice indicates that a single fungal spore was deposited on it when touched compared to the apparent none of the hand washed sample. Not so bad really considering. Eli is right, both methods of cleaning are important, sanitizers of >90% ethanol allow convenience and effective sanitising when you need it. Simple, cheap hand washing when done correctly is slightly more effective again.

Still a great way to engage kids in science and to get them to wash their hands.

Al, MSc Microbiology

Too bad all the focus is on the sandwich and like many other things a form of fear based teaching ! Children should be learning how to keep their immune system strong and how a healthy body and a happy mind has a huge arsenal of tools to deal with invaders.

i rember doing this when i was in 5th grade