Is it healthier to wash dishes by hand or in the dishwasher?

Which way is more environmentally friendly?

Why does your plastic never dry out in the dishwasher?

These are just a few questions that science can answer very clearly. let's see.

Suppose someone in your family is sick. To ensure that these bacteria disappear, is it better to scrub the dishes with your hands or put them in the dishwasher?

If you use a sailor in the dishwasher to wash dishes, your hands will be burned. Dishwashers use hotter water to wash dishes. This super hot water can kill most of the bacteria that grow on dirty dishes.

However, the dishwasher is not without bacteria. Scientific research has found that 100% of dishwashers contain bacteria. Most of these are located near the rubber seals around the dishwasher components. The difference is that in almost 100% of the tests, the bacteria did not harm humans at all. There are many more bacteria in hand-washing dishes, mainly because it is parasitic on the rags, sponges or towels you use.

The answer is: washing dishes in a dishwasher is much cleaner than washing by hands. Even those dishes that are not completely cleaned in the washing machine have fewer bacteria on them than most hand-washed dishes.

Dishwashers require energy and water, and seem to run for a long time. That's not good for the environment. However it is!

Well, it is less harmful to the environment. Compared to washing the same number of dishes in the sink, the dishwasher uses much less water. It's not even close.

However, if you insist on rinsing all dishes before putting them in the dishwasher, some efficiency will be reduced. For all modern and working dishwashers, this is not necessary. The researchers said that just a little rinse is enough. As long as your rinse time is less than two minutes (for the entire dishwasher load), then you are fine.

How about electricity? No electricity is needed to wash hands. Although this seems to be true, it takes a lot of energy to clean water for your use. Therefore, in terms of the environment, the total energy consumption of dishwashers is still lower than that of hand washing. The dishwasher wins here.

If your family has many allergies, you may worry about keeping it as clean as possible. The dishwasher won again, right?

Incorrect! A large number of studies have shown that children who grow up in a super clean environment will eventually be more allergic than children who live in a "normal" environment.

However, to be most accurate, we are actually only talking about young children. By the time you are an adult, your allergies have been basically determined, so this will not have much impact. However, families with babies and young children may want to wash some dishes by hand so that some bacteria can enter their systems. Facts have proved that a little dirt and bacteria in a child’s life can strengthen the immune system and provide a healthier life compared to a child who grew up in an ultra-clean environment.

We will end with a little physics mystery. When you open a complete and clean dishwasher, why are all the glasses, plates, and pots dry and all the plastic completely wet? Worse, why are the bottoms of many plastic cups concave, so they can actually hold water in the dishwasher?

The engineers who designed the bottom of the absorbent plastic should be unemployed. (Sorry-the thread was cut there.) But seriously, why doesn't the plastic dry out?

Glass, ceramics, and metals retain heat better than plastics. This means that these items will stay hot for a longer time after washing. Water molecules evaporate when they gain a certain amount of energy. Since glass, ceramics, and metals last longer, more water will get the energy needed to evaporate compared to the water on the plastic cup.

In short, dishwashers are better for you and the environment in almost all aspects. The exception is if you are trying to introduce some harmless bacteria to strengthen the immune system. If you only need one reason to use the dishwasher-without them, you would spend the equivalent of 10 days a year washing dishes.

Mike Szydlowski is the Science Coordinator for Columbia Public Schools.

Popular quiz time

1. Why is it better for the environment to use so much electricity in a dishwasher?

2. Why may not a household use a dishwasher achieve the energy-saving effect it should?

3. Regardless of whether the dishwasher is fully loaded or not, what impact does it have on the environment if it runs every day?

4. List two reasons why dishwashers are cleaner than hand washing.

5. When do the water molecules on the plate evaporate?

Answers to popular quizzes from last week

1. Do you think our country wastes more or less food than other countries? Why?

We wasted more food. Despite having better storage technology, the amount of food available to us will lead to more waste.

2. What energy do you think is needed to make a hamburger?

You have to provide food and water for the cows, you have to water the plants that the cows eat, you have to process the cows into meat, you have to pack and transport the meat, you have to keep the meat cold, plus all the energy needed to make bread.

3. If a family buys 300 pounds of food a month, how much does it actually consume?

Consumers waste 40% of what they buy, so they consume 60%.

4. If the same family spent $500 on the food above, how much did they waste?

5. Why is it best to make a weekly menu for your family?

You can better plan your food purchases in order to use it more. This will save energy and a lot of money.