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Hand Washing Science Experiment for Kids

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What hand-cleaning method is best? This fun hand washing science project brings to life the importance of handwashing for kids.

We took the science experiment for kids even further with our own hand washing science experiment!

If you love this gross science experiment, check out the complete list of Halloween STEM activities for middle school!

What hand-cleaning method is best? This fun hand washing science hand washing science project brings to life the importance of handwashing for kids.

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What is the Hand Washing Science Experiment?

In a bacteria hand washing experiment, kids are able to see just how many germs are accumulated on their hands after playing, even after they wash their hands!

Try this fun hand washing experiment to convince kids once and for all that they really do need to wash their hands with hot water and soap.

We’ve been on a picture book kick recently. Monkey was never that interested in storybooks, but Bo is a big fan. One of her favorites (because she’s just a gross-lover at heart) is Germs! An Epic Tale on a Tiny Scale.

In this book, a little bacteria just doesn’t understand why he has to fight for control of the toilet when the little boy/girl is so nice!

I love the adorable way that the book shows the battle between bacteria and soap and why you should ALWAYS wash your hand after using the bathroom.

science fair project germs hand washing

What you’ll need for the germs science experiment:

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Bo kind of hates washing her hands, so I thought a hand washing experiment would be the perfect way to show her that hand washing is important.

First, before doing the experiment, we read the Germs! book. It’s super-cute.

Next, we tried our own handwashing experiment.

How Long Should You Wash Your Hands?

hand washing science experiment

We didn’t test the length of handwashing sessions, rather, hand cleansing methods. But according to the CDC, the recommended time is between 20 and 40 seconds with soap and as hot of water as you can stand.

How Clean Are Your Hands Science Fair Project

hand washing experiment

In our experiment, we used six agar plates.

The goal of the experiment was to see which hand washing method was the most effective at stopping/slowing the spread of bacteria.

For each plate, I had Bo lick her fingers, then wash her hands in a certain way.

We used the following hand washing methods:

  • No washing (control group)
  • Washing with cold water
  • Washing with hot water
  • Washing with cold water and soap
  • Washing with hot water and soap
  • Using sanitizer

After washing and drying her hands, Bo touched her fingers to the surface of each agar plate. We labeled them with a duct tape strip and a permanent marker to keep track.

The agar plates went on top of the fridge, and we waited about a week.

Here is what they looked like before the bacteria grew:

Have you read the book Germs? This fun hand washing science experiment brings to life the importance of hand washing for little ones.

And here is what they looked like a week later:

Have you read the book Germs? This fun hand washing science experiment brings to life the importance of hand washing for little ones.

Washing Hands Science Experiment Results

germs science experiment

Unsurprisingly (to me), the hot water and soap and the sanitizer plates remained the cleanest after a week. However, I was surprised to see that cold water and soap did so poorly at killing bacteria.

Have you read the book Germs? This fun hand washing science experiment brings to life the importance of hand washing for little ones.

I really thought there would be a major difference between the soap plates and the non-soap plates, but there really wasn’t much at all!

That just goes to show that if you’re not washing your hands for long enough, then you aren’t actually cleaning your hands well enough.

Inform kids that they need to wash their hands for 2 happy birthday songs in warm water and scrub under nails and between fingers for a true clean.

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