Today’s Wonder of the Day was inspired by Valmae. Valmae Wonders, “Do automstic doors need electricity to work?” Thanks for WONDERing with us, Valmae!

There you are, getting ready to leave the supermarket. Your hands are full of bags of groceries. You get to the door. How are you going to open it with your hands full? You’re thinking of setting some bags down. Just then, the doors open with a “Swoosh!” as if by magic!

What’s going on here? Is something supernatural at work? Is there a ghost standing nearby opening the doors for people leaving the supermarket? Nope! Would you believe it’s pure science and technology?

It’s true. Those doors—known as automatic doors—open and close with the help of technology, not magic. Automatic doors operate with the help of sensors. Sensors do exactly what they sound like they’d do: they sense things. There are many different types of sensors. Most of them sense sound, light, pressure, or motion.

For example, some automatic doors operate when they’re triggered by sensors that sense pressure. These pressure sensors might be disguised in a rubber mat in front of the door. When you step on the mat, the sensors send a signal to the automatic doors. That’s how they know to open.

Other automatic doors operate on optic or motion sensors. These sensors might be mounted above a set of automatic doors. They may also be built on door frame. When these optic or motion sensors sense motion nearby, they trigger the automatic doors to open and then close. They will open as soon as you get close enough to activate the sensors.

Automatic doors have many useful purposes, which is why you can find them in many different types of locations. From supermarkets to airports and other large buildings, automatic doors make it easier for people to get into and out of buildings. They are especially helpful for people who have a disability.

Similar to revolving doors, automatic doors also help to save energy. They limit the amount of time that doors are open, which helps the building maintain its temperature. And, of course, they’re very helpful when it’s time to head to the car!

Standards: CCRA.L.3, CCRA.L.6, CCRA.R.1, CCRA.R.2, CCRA.R.4, CCRA.R.10, CCRA.SL.1

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Tomorrow’s Wonder of the Day will stop you in your tracks!