# Density of Theraband



## JasonP (Jan 4, 2012)

I am conducting allot of calculations to help my knowledge of theoretical slingshot performance. One critical piece of data I am missing is the density of Theraband products (most importantly gold). If anyone knows where I could find this data that would be great. If anyone who has a large piece of Theraband could please weigh it using accurate scales and post the bands colour, dimensions and weight it would be greatly appreciated.

So far I have created software that calculates the velocity of various slingshots with remarkable accuracy, knowing the density of Therabands would help to improve the accuracy of the calculations. I usually only use this to view 'trends' to see how variables interrelate rather than focusing on the exact values.


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## Jim Williams (Jul 6, 2011)

That sounds like a very interesting project I like your style, the only problem I think you may encounter is I have found different batches of theraband to be a slightly different thickness. I don't have any theraband that isn't attached to a catapult at the moment but when my order arrives I will gladly weigh it for you with digital scales if someone hasn't already done it. Good luck!


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## JasonP (Jan 4, 2012)

Thank you very much for your support Sling Jim, I look forward to your results regardless of whether you are the first to post, all data is useful to me. Small variations between batches do not faze me as we would only be talking fractions of grams, for most setups it would equate variations in the centimetres per second. When I’m done I will post the equations and an excel spreadsheet that crunches the numbers.


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## Jim Williams (Jul 6, 2011)

What are you writing your software in fella? If you could put the data into graphs that showed power/trajectory with different ammunition that would be pretty cool and give an idea of difference between say flat single/double theraband and tubes etc.


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## JasonP (Jan 4, 2012)

Already working on it and have made such graphs already, the accuracey of these graphs depend appon my imupt values and so far for band weight im just guesing by the feel of my own sets. This is why I need the density values.


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## Charles (Aug 26, 2010)

I have some Theraband gold ... I think they are the "standard" exercise bands, cut about 6 inches wide by about 5 feet long. If my little scale is up to it, I could weigh a length. But to get a precise volume is the problem. I can try the old Archimedes trick, but I do not have a true grduated cylinder. Still, I will look in the kitchen to see what sort of measuring cups I have that might be suitable.

If I do not get to it within a day or so, fire me a PM to remind me.

Cheers ...... Charles


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## Charles (Aug 26, 2010)

I have two pieces of Theraband gold. Each is 72 inches long, and 5.5 inches wide. I have seen a couple of figures for the thickness of Theraband gold ... one was .025 inches and the other was .027 inches. Take the average at .026. That gives a volume of 10.3 cubic inches, or 168.8 cubic cm, for each of my pieces. Averaging the weight of the two pieces gives 182 gm per piece. So the density of Theraband gold is about 182/168.8 or 1.08 grams per cubic centimeter, more or less. I hope this is the figure you need.

Cheers ....... Charles


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## JasonP (Jan 4, 2012)

Thanks Charles! Those numbers are exactely what i needed!


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## JasonP (Jan 4, 2012)

just an example of the output, 15mm steel useing double 3x3x36cm gold bands drawn to 1.75m

band mass 30.8 g Draw weight 15.5 kg, projectile mass 13.8 g, Velocity 82.4 m/s, Ek 47.0 j

any one know how to upload tables and charts?


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## Charles (Aug 26, 2010)

JasonP said:


> just an example of the output, 15mm steel useing double 3x3x36cm gold bands drawn to 1.75m
> 
> band mass 30.8 g Draw weight 15.5 kg, projectile mass 13.8 g, Velocity 82.4 m/s, Ek 47.0 j
> 
> any one know how to upload tables and charts?


Save your table or chart as a pdf or a jpg. Then just treat it as a photo for uploading.

Cheers ...... Charles


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## jrpicks (12 mo ago)

I need to do some similar calculations for a physics project at school. Is the software public?


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## olenickdesigns (Oct 2, 2021)

jrpicks said:


> I need to do some similar calculations for a physics project at school. Is the software public?


someone else on the forums might have seen him under a different screen name, otherwise he just had 3 posts ever. i didnt see any of them leading to any sort of information at all about his project besides inquires. maybe someone else on the forum has seen such software though.


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## Crac (Mar 3, 2013)

@*jrpicks*
I've sent you a message, maybe we talk some time this week?


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