When I was small I had a toy measuring tape that marked every centimeter (about 0.4 inches). I came to the conclusion that a centimeter is the smallest unit of length. So when something was, let's say, 0.5 centimeters long, I though it's either a measurement error or a pure illusion.
science
1,002 beliefs in this area

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I used to think that when you were on the phone, the person you were speaking to would shrink themselves and crawl up the wire and sit in the handset.
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My mum believed that cold water would come to a boil sooner than warm water so I believed it too until school set me straight.
For a few months, I used to believe that everytime you hit the space bar, more space is generated in the sky and outer space. Maybe it is true, because nobody knows how big outer space and the sky is.
I used to believe that if you yelled "911" in a tin can phone, it would really work and the police will come and arrest you if there's no emergency. When my best friend and I were in 3rd grade, we tried using a tin can phone and I yelled "911" to her. My best friend told me it's illegal to call 911 when there's no emergency, so both of us got scared and we ran into the house and hid under the table so the police couldn't find us. We were stupid at that time.
When I was 10 I was jealous of the fact that my friend had a cell phone and I didn't, and when I asked my mother why this was she told me that it was because prolonged cell phone use could cause brain cancer. From then onwards and up until the age of 12, I straight-up refused to use cell phones (even in emergencies) and I even used to go around "warning" people about the dangers of using them. Then, up until the age of 13, I would only use cell phones when absolutely necessary. It wasn't until the age of 14 when I learned in physics class that the waves emitted from cell phones pose no health risk.
When my mother was little, she believed that every time you put a record on the musicians would have to play the music. As a result, she never played records in the evenings or at weekends so the musicians could have some time off.
I remember hearing paedophile on the news a lot and I became familiar with computers while i was young. I honestly believed the PDF was short for pedophile since file is pbviously connected to documents.
e.g. I'll attach a pedophile to the email.
When I was I child, I used to believe I was reaincarnation of Marie Curie. Why? I loved spending my time doing some strange experimentsand I was in search of a new way to help sick people.
I used to believe that Windows was written in QBASIC. (This was at the time of Windows 3.1.)
I used to believe every person was connected by thin threads, only when I became older I realized my mother was referring to DNA. This was when I was about 10 years old.
I used to believe that if you thought really hard about who you wanted to phone and pressed the pound button, it would automatically call the number you were concentrating on. I couldn't understand why anyone would ever use any other method. I swear it worked for me until someone told me that it wasn't possible.
I used to believe that an elevator was a magical room that teleported you somewhere else in the building. Then i learned that this "magical room" was just a box hoisted up by a machine.
One of my first days in preschool I stepped on a crack and one of my classmates freaked out saying that I just broke my mom's back. When my mom picked me up I apologized profusely but instead of setting me straight she replied, "I was wondering why my back hurt all day." I avoided cracks for years until one day I got mad at my mom and stomped on a crack repeatedly. When it didn't work I assumed that it only worked with some cracks and continued avoiding cracks for an embarrassingly long time.
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I used to believe that FAX send real papers.
I thought that FAX documents went through the electric line. No one told me the structure of FAX.
My parents got our first computer when I was about 9 and windows 95 was just released. I had no idea what I was doing and was just going through all the random "folders" looking for games. My cousin's computer had Oregon Trail, and this computer was way better so my "Oregon Trail" game must be amazing!
I must have done something wrong and the computer froze up saying "This program has been shut down due to an illegal operation." I FREAKED OUT and unplugged EVERYTHING from the computer... The power, the screen, the keyboard, mouse, and the printer before hiding under my bed for hours. I was convinced 'they' were coming to arrest me for breaking some law. I remember literally crying that I was going to be taken away in handcuffs.
I used to think that calculators worked because someone had preprogrammed all the answers into them ahead of time, and I pictured people in factories programming all the answers in, one calculator at a time. When they came out with calculators that could display more digits, that only made things more amazing because of how many more answers they had to program!
When I was a kid, I used to believe a nuclear plant was a clouds plant and could make magic clouds.
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When i was a between the ages 3 and 6 I used to think that the moon followed me everywhere i went.
After I learned what H20 meant, I thought that faucets worked by combining hydrogen and oxygen atoms in the pipe when you turned it on.