My grandmother lived next to a cemetery. Streets are boring - me and my cousins played in the cemetery 
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My 8th grade science teacher let us play with mercury in class - this was in the mid-70s.
Same here. Middle school in the mid-70s. I distinctly remember pushing my finger into a beaker full of it and noting that my finger didn’t get “wet”, and the science teacher saying that it’s because it has very high surface tension.
Years later I keep wondering if I had a cut or scab on my hand at the time. 
Made a mercury switch with mercury, an old Testors model paint bottle an old night light and an old lamp cord. Lot’s of electrical tape involved.
So, I mounted this set up inside the lid of my record player so when you lifted the lid, a light would come on and illuminate the record. I was maybe 12yo, say early 70’s.
I was never bored. I’ll say that for sure.
As far as I can tell, this is still universally done in every household with kids.
Oh yeah!
I was pretty much free rein, but limited to where I could go on my bike. Public transportation in L.A. sucked even more back then. Watching the Stephen Stills/ Billy Porter video at the DNC this year brought back old memories of driving on Sunset Strip days after the Sunset Strip riots. I was too young to drive, but I had friends a year or two older. I remember it as very cool.
Always walked to school starting in kindergarten – about a mile and half away – with two big streets to cross (Washington and Culver Blvds). But we always avoided the little grocery on the way, because we were told the owner was a “creep.” In hindsight, I’m thinking, based on how they talked about it, that he was a pedophile. We went instead to a tiny store created out of a house in the middle of a residential block. Little wax bottles with “coke” in them. Candy cigarettes. Black licorice (I have always hated red vines). Bonfires on the beach (they’re illegal now!).
A lot of boys (some as young 10 or so) had mini-bikes or dirt bikes when I was growing up in the late 60s and early 70s. My next-door neighbor had a go-kart when he was a teenager too - not street legal, so he’d wait until the street was real quiet, do two or three hot laps around the block and then put the kart back in the garage.
There was never any reason not to. But when you could buy a roll of cookie dough that had been on store shelves for months, there were warnings that pathogens had enough time to develop.
They were still legal in SoCal when I was in high school. Instead of going to the prom my senior year my girlfriend and I went to Disneyland then spent the night on the beach. Now days they’d either roust you off the beach or clean up your mangled corpse in the morning.
Do kids still pants each other or would that be criminal assault now? When I was in high school during an actual assembly some freshman kid got pansted as a prank and his dong flopped out for his entire fellow student body to see and the kid who pansted him was still at school for the rest of the week like nothing happened.
1950s-early 1960s - For years I walked the almost one mile route to/from school - as well as to/from home at lunch time - no matter what the weather. Very few of the many hundreds of students were allowed to have lunch at school.
Our dead-end street had (fairly busy) railroad tracks at the end - accessible via an 8-foot fence and a sharp drop through assorted vegetation (with assorted small wildlife- skunks, raccoons, etc.). Likewise - the climb up the other side to explore the new houses under construction. Not to mention the slow-moving freight trains that could provide a short ride.
Oddly, I never liked the stuff.
Already mentioned, but I remember traveling to away games in little league in the back of a beat up pickup truck. Curvy, two lane country roads where traffic goes 45-55mph. The next town might be 20 miles away. Thinking about it today makes me shudder, but it was exhilarating at the time.
I had a male math teacher in 6th grade who routinely teased girls in class. I don’t think he was a diddler or anything like that, but it was absolutely sexual harassment. Looking back, it blows my mind that this behavior was considered “normal”. This was in the 80’s.
My brother and I called them “cookie embryos.” We were strange children.
When I was 10 my older brother (15 years older) came home for a visit. He took me back to his house in Minnesota to spend part of the summer. When it was time for me to go home, he took me to the train depot in Minneapolis and put me on a train to Omaha. I had a small suitcase with sandwiches and books to read on the trip. I had a ticket and the conductor helped me change trains in Chicago.
This was in 1963
I don’t really find that to be true. The overprotective parents tend to be in their late 20s to early 40s, and the ones complaining most bitterly about kids being useless are in their 50s and 60s.
As for the OP, I babysat my brother all day during all our school vacations, including summers, starting when he was six and I was twelve. A lot of people these days won’t allow a twelve-year-old to spend a couple hours by themselves.
Every boy was armed with a jack-knife, especially at schoool, from about third grade. At recess, we’d throw them at trees to try to make then stick. My dad bought a switchblade to keep in his tackle-box, I carried that until I got bored. I carried a Swiss in my pocket eveery day of my life until I was 75 and a neighbor expressed horror when I got it out to use the screw driver. Told me I could arrested for walking across the street with it “concealed”.
I bought beer and cigarettes for my father with a note from him to the local liquor store owner as a pre-teen.
Teens couldn’t do this, liquor store owner would know the teens would drink the beer and smoke the cigarettes.
Back through the early Seventies you could drive your vehicle on many of the beaches of the Outer Banks of North Carolina. I can remember often zipping along the beach in a Jeep with my parents and sisters and cousins, no doors on the vehicle and no one wearing seatbelts. Great fun but absolutely verboten now.