We’ve always known that it’s important to wash our hands, especially during cold and flu season, but now that we’re in the middle of a global pandemic, keeping our hands clean is something that’s on our minds more than ever.

Perhaps you’ve been singing “Happy Birthday” in the bathroom every time you wash your hands. Perhaps you’ve been singing along with “Baby Shark” instead. Perhaps you haven’t been singing at all. As long as you’re washing your hands correctly, and often, you’re good to go.

You might be saying to yourself, “Can’t I use hand sanitizer instead?” We’re told that hand sanitizer is useful when we can’t get to soap and water, but in no way should it be used as a substitute for washing our hands. If you’re not convinced that using good ol’ soap and water to clean your hands works better than hand sanitizer, you will be after you hear about the science project one elementary teacher did with her class.

The project was simple, but before we tell you about it, we need to warn you that we don’t recommend looking at the following pictures while you’re eating. They’ll probably kill your appetite, especially if you’re eating a sandwich and you haven’t washed your hands.

The teacher bought a loaf of white bread. She transferred one piece of bread to a ziplock bag without ever touching it. That was the control piece.

Then she had all of her students touch a piece of bread without washing their hands.

Then, she had everyone use hand sanitizer to clean their hands before touching the next piece of bread.

Finally, she had everyone wash their hands with soap and water before touching a fourth piece of bread.

Oh, wait. There’s one more piece of bread. They wiped this piece of bread on all of the Chromebooks in the classroom. Ever wonder how many germs are lurking on your laptop? You’re about to have a very good idea.

It’s amazing how the piece of bread the students touched after washing their hands with soap and water looks almost identical to the piece of bread that wasn’t touched at all. Using soap and water is very clearly superior to hand sanitizer, yet hand sanitizer if very clearly superior to doing nothing at all.

If your kids don’t understand the importance of washing their hands, you could easily recreate this experiment at home.

Did you know that washing your hands made such a big difference?