What Do Washing Machines and Ultrasonic Jewelry Cleaners Have in Common?

The short answer is mostly everything. The difference is in the details. Let me explain.

A gift from Santa this Christmas was an ultrasonic jewelry cleaner. Who am I fooling? I asked my husband to get me one for Christmas. And a dutiful Santa he was. I then proceeded to clean every piece of jewelry in my possession, except for the ones I knew shouldn’t go in. Reading the manual expanded on those exclusions. Then I thought readers should be aware of what shouldn’t go into an ultrasonic jewelry cleaner. Hence, the article entitled How to Clean Your Jewelry Safely with an Ultrasonic Cleaner was born.

The ultrasonic jewelry cleaner cleans jewelry with sound vibrations. Oh, yeah, there’s a little detergent and hot water to help the cleaning along. But, for the most part, high-frequency sound waves are shaking the dirt off your diamonds.

Thinking about that raised a question in my mind. Why can’t we use high-frequency sound waves to wash clothes? An ultrasonic washing machine! Like the dirty diamonds sitting in hot soapy water, can clothes in a washing machine with warm water and a cup of Tide get clean by the action of high frequency sound waves?

They can, said the resident physicist, otherwise known as my husband and sometimes Santa. I posed the question to him, expecting a comment about the ludicrous question while not expecting the answer I got. He qualified the positive response by declaring the cleaning would be terribly inefficient and expensive.

Why expensive? Well, you need to put in a lot of energy to vibrate the clothes in the washer at the same high frequency the jewelry in the ultrasonic cleaner is being vibrated.

Why inefficient? The amplitude of the sound waves in the ultrasonic cleaner is low. Both the big washing machine and the tiny ultrasonic cleaner ‘shake’ dirt off. But while the fast but tiny shaking of the ultrasound works great for jewelry, it won’t work nearly as efficiently as the slow, large shaking of your load of clothes in a big washing machine tub.

Actually, washing machines do operate on the same principle as ultrasonic jewelry cleaners. Okay, you lost me on that one. You’ll have to explain that in terms I can understand.

It’s simple. Ultrasonic jewelry cleaners operate with high frequency, low amplitude sound. Washing machines operate with low frequency, high amplitude sound. I got it, I’m thinking: same principle, diametrically opposed. You cannot hear the high-frequency sound of the ultrasonic cleaner. It’s too high-pitched to hear it. You cannot hear the sound of the washing machine agitator. It’s too low-frequency to hear it. The human ear has a limited range of vibration frequencies that it can detect. Both machines are cleaning with sound waves essentially, albeit ones in opposing ranges of frequency and amplitude, and both with the help of water, heat, and surfactant.

What an epiphany! If two such seemingly dissimilar things can operate on similar principles, there’s hope for the rest of us. We just need to dig deeper in our seeming differences to find similarities in our operating principles! Even if we can’t hear the extremes and need help from others.

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