When my sister and I were younger we fought a lot (I love her to death now).

I remember how she always liked to play with my mother's make-up and perfume in the bathroom, and she'd spray ALL the different perfumes a lot and make it smell horrible. With only one bathroom to share, that kinda sucked.

One day after she sprayed a whole bunch, I had to pee and found what she was doing. I was annoyed, so I told her that mixing different chemicals can create an explosion. Then I locked her in the bathroom, holding the door from the outside. After I took off, she told on me.

The BEST part about that was that when she told my Dad, he responded something like, "Well, technically you never know what shouldn't be mixed..."

Anon

Early in my becoming acquainted with science, I thought the density of all elements would be proportional to their atomic weights, regardless of whether they were solids, liquids, or gases. I "figured out" some amazing things based on that. For one thing I wanted to do a demonstration that I never got to do because of the difficulty of obtaining the heavy gas xenon. I thought that if only I could get some xenon and fill a beaker with it, I could do an amazing demonstration. For one thing I thought the xenon would be so heavy that it would stay in the beaker without dispersing into the atmosphere for quite some time. Then I thought I'd place a piece of iron on top of the xenon in the beaker and see the iron float on the xenon. Since xenon has a considerably higher atomic weight than iron, I assumed that even gasseous xenon would be denser than solid iron, resulting in that floating of the iron that I expected. When I later learned about the behaviour of gasses, I realized that gasseous xenon, for all its large atomic weight is much less dense than most any solid, including iron, so likely no solid would float on it. And even a heavy gas would disperse into the atmosphere quickly, so the xenon wouldn't likely stay in the beaker long enough for me to even try the demonstration.
Another amazing "fact" I deduced on the same basis came after I first heard of osteoporosis, and how it is a disease causing loss of bone density. I knew that bones have a lot of calcium, an element of considerably larger atomic weight than nitrogen and oxygen that make up most of the atmosphere. But human flesh, I learned, is composed primarily of hydrogen, carbon, nitrogen, and oxygen. Since hydrogen and carbon have lower atomic weights than the latter two that also make up air (99% or air, anyway), I deduced that human flesh must be lighter than air, so that our heavier bones were what holds us down. So I thought that the main risk of osteoporosis sufferers was that their bones could become so depleted of calcium that their bodies' overall density would be less than that of air, and they could go floating away to the top of the atmosphere!

Shelley

once when i was very young i thought anything you wanted to kill or get rid of should be thrown in the fire. well lets just say big metal objects dont burn very well

william howard

Once my dad told me that sometimes glass bottles in the bush start bushfires when the sun shines through them (true). I spent months shining torches on glass bottles stuffed with paper to see if this was true, no such luck.

Steve

I used to believe that if you mixed exactly the right amount of each colour of poster paint, you would make white. I spent hours staring at a brown pot of paint, gently adding another dab of blue (or whichever) thinking I must be doing it wrong!

Anon

In my second year at school, we were told that water froze to become ice and that ice could melt to become liquid. I thought that liquid must somehow be different to the water it once was and would be very reluctant to ever drink it.

cc

This one isn't mine, but it's one my daughter picked up from me one day when we were driving. She was about 4 years old at the time and we were driving to the zoo for the day. We were passing a power plant with the two large steam silos that were giving off quite a bit of steam. My daughter asked me "Is that where clouds come from?", I was only half paying attention to here remark because I was driving but I responded, yes. We were driving the other day and she called me out on it. She's now 15 and knows better, but we both laughed as she confessed that she believed that's where the clouds came from until she was about 8.

Dan

I used to believe that you could die from looking at a can of chemicals because I thought the chemicals would lunge at you and rot your eyes out.

Young and Stupid

I used to believe that if you touch the "metal" end at a lightbulb you`d get electric shock and die. to this day I still avoid holding a bulb at the end.

Caroline

I am 16 and a sophomore in high school. I believed from the time I knew what an atomic bomb was to today (August 19th 2008) that when things in close proximity to the blast are vaporized, that they just disappear. I was informed by my chemistry class and teacher that they do not, in fact, "turn into air" rather they are converted into extremely small particles that are lighter than air. Silly me.

Kara Collett

I used to wonder why, if fire is orange, does it turn things black? As a matter of fact, I'm still wondering!

Rachel

when i was young my sister made me believe that vinegar would burn me badly if i got it on my skin because it was acid

diddymonster

I thought the chemicals in chemistry sets couldn't really blow up in real life I thought it was only on the cartoons, so I was wondering why when I asked my mom for a chemistry set when I was eight my mom had said "ARE YOU KIDDING YOU'D BLOW US ALL UP IN HERE"

very confused at age eight

Used to think that a pile of oily rags could catch on fire by themselves. (Sponteanous combustion)

Frank

My freind and me had an obsession with fire. and yes were girls. well one day i found the lighter my mom ussually hid from me. i thought that water was flammable, and if you mixed it goldfish a magical fish woould appear, and it would be green and made of playdoh. OK i was creative ( : anyway we got the lighter and found some water and a pack of goldfish. we put it in the toilet. the we threw the lighter in and screamed "FIRE!!!!!!!!!!!!!" because when people saw fire thats what they yelled so we thought that what made it catch on fire. My mom jus locked me in a cage till i was 10.

QuaKo

the other month I mentioned to a friend that I spray on 3 different deoderent and 2 different perfumes every morning. He looked at me in shock and said 'you can't do that! the chemicals in them will mix together and cause an explosion or form a poison. you could die!' I spent the rest of the day waiting for something to happen to me, I was scared that at any moment I could explode. For weeks after I wore only one deoderent, until finally someone told me that it wasn't true.

squizy rach

Until I learned about it in eighth grade, I thought the periodic table didn't always look the same way. It made sense to me that it could be rearranged, since it looked like such a crazy shape already.
This belief probably arose from the fact that, because of that crazy shape, I could never remember what it looked like between the times I saw it.

Aretia

We were taught about AIDS before we were taught about viruses. We learned about viruses in middle school. But, of course, even in middle school, they had to teach us about AIDS first. Pretty much, all we knew about AIDS was that it had something to do with RNA and Helper T-cells, since those were the words they kept using. So up until high school, I always associated RNA as a diseased DNA.
So they described the process of how the AIDS virus spreads: the virus attaches onto a white blood cell and injects some of itself into the cell. The little viruses multiply and become more viruses until the cell is so stuffed with viruses that it explodes with lots of little AIDS viruses.
Very smart of them to teach us about AIDS before teaching us about viruses IN GENERAL.
See, the way AIDS infects the body is THE SAME WAY ALL VIRUSES INFECT THE BODY. But I didn't know that. So for years, I thought that all viruses that spread like that (which would be all viruses) were AIDS!

Anon

When I was a child, I used to think that matter could be created and destroyed.

Anon