Comment by hydrogen7800
3 days ago
>Roll a ball off of a standard classroom table. Use a 1990s wristwatch's stopwatch mechanism to start the clock when the ball rolls of the table. Stop the stopwatch when the ball hits the floor.
Our class had some kind of device that would either punch a hole, or make a mark on paper at a regular time interval. We attached a narrow strip of paper to the ball, and let it pull through the marking device as it fell from the bench to the floor. We then measured the distance between each mark, noting that the distance increased with each interval, using this to calculate g. I don't recall anything more than that, or how I did on that lab. I received a 50 one marking period for lack of handing in labs, but had a 90+ average otherwise in the class.
In the UK we called it ticket tape and it was terrible. The devices barely worked and they cause a bunch of friction so you end up calculating a value of 'g' that's off by like 30%.
I think officially, we called it ticker tape, as in stock ticker - it was originally used to record stock prices transmit by telegraph.
That's an interesting way to measure the passage of time -- just use something that produces a "regular distance" and derive a way from kinematics to calculate the acceleration from the change in the distance.
The way boats historically measured speed was by dragging a rope behind them. The rope has knots tied with exact spacing. You drop one end of the rope in the water, and count how many knots pass you in a given time. That's then your speed in knots.
Using this method repeatedly to guess how far you've moved over the course of days is, historically, a fantastic way to crash into the side of France in the middle of the night.
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> You drop one end of the rope in the water, and count how many knots pass you in a given time.
Given that you're dragging the rope behind you, won't this number be zero?
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Ticker tape timer. My class had the same thing for the same experiment.
... like something that burns a hole in the paper with a spark or marks thermal paper with a burst of heat.