Scotch Tape Clock

Did you know that a roll of regular scotch tape can take you back in time? More specifically to the times when time itself was measured by observing liquid and solid objects obeying laws of gravity. I'm speaking about water clocks and weight driwen mechanisms.

Atomic clocks and milenias of technical progress - you can throw all that away because now we have scotch tape to measure time. And why would you want anything different?

So, this is where I've got this idea from.

One day I've been tinkering with some stuff for my entry to the Tape Contest. Yes, at two Am... Yes I call it a day... Anyway, I've left two rolls of tape hanging out from the edge of the table, which is the way do when working with sticky tapes.

Some time later I've discovered that the rolls had unrolled themselves. And obviously it must have been happenned at some rate, which meant that I could measure time with it... maybe.

So I decided to concieve an experiment. And this is where I'd like you to join me.

First of all you'll need some board. Well, actually you can go along without any board and use a wall or your room door instead. But I think it'll be better with some board. I used a cut-off piece of some laminated particle board.

I've attached a strip of masking tape to it. It'll serve us for leaving marks and creating a scale.

And a regular pencil will serve us as an indicator.

Take a couple of soda bottles caps and make holes in the middle to put them snuggly onto the pencil. They will secure it on the tape roll.

Make sure the pencil rolls freely on the roll.

Now unroll some tape and secure the end on the board. The sticky side should be facing forward (you).

Place the indicator pencil inside the roll.

Mark the start point as current time.

From now we'll be marking time segments according to a regular clock to create a scale. I choose 30 min increments.

Over the time the roll of tape will steadily unroll itself due to the force of gravity.

It took four hours for my roll to cover all the lenght of the board.

To restart the clock you have to cut off the tape that has unrolled and wrap it onto the pencil. This way you make sure that the weight of the roll remains the same and the rate of unraveling is preserved. But, to be honest, I've found it kind-of hard to roll the tape onto the pencil accurately enough.

One thing I've noticed is that the roll unrolls itself at a different rate depending on how far has it went from the starting point. It results in about two centimeters of discrepancy of the scale. It caused because the geometry of the system changes over the time causing the forces being applyed at a different angle. Itryed to show this at the picture.

If you want to get more accurate result with this device I can suggest adding a ledge to the top of the board for securing the end of the tape equal to the radius of the roll.

Another thing is that having to reset the clock every four hours, like it was in my case, is less than ideal. You can decrease the rate of unrolling by using some old well used roll of tape that is lighter in weight.

But having your increments of tie slower will result in your scale being more dense, meaning that you have to able to make marks on is as well as readings from it more precise. So, to make it easier I can suggest adding a raised bar to your board to elevate the scale closer to the indicator.

So, what this instructable is about? You kind of can use a roll of scotch tape to tell time. It was an experiment. Can you make any precise clock this way? No. Probably not. As tests showed , even the second launch of the roll revealed a few minutes deviation from the scale. It sepends of many factors, such as: the angle of the board is positioned, environment temperature,brand of the tape, atc. This is something you would like to present on a science fair or do with your kids. Also it's kind of a piece of kinetic art..

Anyway, this is it for today, thanks for your attention, and have a nice tape.