Simple Balloon "Rocket"...

The mass is going to be 100 g, not 5 g. Here is the scale I will be using.
http://www.hornady.com/store/GS-1500-Grain-Electronic-Scale

Ok, fair enough, let me know what you come up with.

This single claim proves unequivocally that sceptimatic has absolutely zero understanding of mass, weight, density, and pressure.

At a guess...and this is just a guess. I'll say you should get a reading of minus 5 grammes.

Even his guesses are ludicrous!  I'm left wondering if the poor guy ever studied high-school science?  All the evidence points to the negative LOL.

Now something can "weigh" minus 5g.  (Pardon me a moment whilst I adjust my underwear.)

This single claim proves unequivocally that sceptimatic has absolutely zero understanding of mass, weight, density, and pressure.

Quote

At a guess...and this is just a guess. I'll say you should get a reading of minus 5 grammes.

Even his guesses are ludicrous!  I'm left wondering if the poor guy ever studied high-school science?  All the evidence points to the negative LOL.

Now something can "weigh" minus 5g.  (Pardon me a moment whilst I adjust my underwear.)

I don't see how you have a problem with that.

This single claim proves unequivocally that sceptimatic has absolutely zero understanding of mass, weight, density, and pressure.

Quote

At a guess...and this is just a guess. I'll say you should get a reading of minus 5 grammes.

Even his guesses are ludicrous!  I'm left wondering if the poor guy ever studied high-school science?  All the evidence points to the negative LOL.

Now something can "weigh" minus 5g.  (Pardon me a moment whilst I adjust my underwear.)

I think I confused him when I said scales can read negative. They can read negative when tared on a mass. 

Quote from: ausGeoff on November 21, 2014, 09:10:25 AM

This single claim proves unequivocally that sceptimatic has absolutely zero understanding of mass, weight, density, and pressure.

Quote

At a guess...and this is just a guess. I'll say you should get a reading of minus 5 grammes.

Even his guesses are ludicrous!  I'm left wondering if the poor guy ever studied high-school science?  All the evidence points to the negative LOL.

Now something can "weigh" minus 5g.  (Pardon me a moment whilst I adjust my underwear.)

I think I confused him when I said scales can read negative. They can read negative when tared on a mass.

There's no confusion here. Once you set the scales for tare weight, then you add your mass. This is when you put it into the vacuum chamber and evacuate the 10 psi you said it evacuates.
You are now saying you are using a 100g weight, so naturally my guess will have to change to minus 100g reading. If your scales  cannot show a minus reading then you have to alter them to cater for that.

Manual kitchen scales can read minus by simply pulling up the plate, so if your digital ones can do that, then it's fine to just do your tare weight, then add your 100g and stick it in.

Believe it or not, you already are. Every time you place any mass on a scale, you are not measuring the mass, you are measuring the resistance of that masses push against the atmospheric pressure above it by what it displaces due to it's density.

No, silly, I ofc meant measuring it directly. With a pressure transducer for an example, if I calibrate it to zero sitting on my desk by itself and then for an example place the sensor head
at surface of a massive object, should the pressure reading change? Or if I attach it to a massive object, so that the sensor head is more or less flush with the surface, should I then see a change in the reading?

No, I mean it exactly how I said it. The object and its density displaces the atmosphere that it finds itself in, whether it's on the deck or hoisted up in the air. It will displace whatever cannot be absorbed into it, as I explained with the lead and the sponge.

I can't accept that. A sponge can 'absorb' fluids into it, but completely solid materials weigh different amounts too. When I submerge a 10cm³ solid object in a 10l bucket filled with a fluid, exactly one liter will be displaced & 9 liters will remain, completely regardless of the object's density/mass/weight.

The reason I thought you might have a different meaning for the word displace is that I've never before heard anyone speak of pressure being displaced.

Imagine you throw that ball up into the air at 1000 mph (for instance). If you slowed the camera down, you would see the front of the medicine ball compress a good bit. Basically it's expanded itself sideways or down its sides, creating a super fast friction around it due to the compressed top of the ball. This friction would heat up the ball, creating a lower pressure around and back under it which has to be equalised and it does by a squeeze of atmosphere against that lower pressure.
the best way I can describe it without confusing it, is by imagining the ball being a wet bar of soap in your hand and you are trying to grab  it and squeezing it up every time you do. As long as your energy is applied like that, it will keep going.
As soon as you stop, then the friction against the compression up top, starts to exert that force back due to you no longer applying energy.

Does this mean that the thermal energy contained by the ball is a major component in production of the force that keeps it moving after I've released it? It's not the pressure above it by itself, which is pushing the ball down, but the thermal energy and the effects of pressure equalization combined that produce a force that drives the ball up?

There's no confusion here. Once you set the scales for tare weight, then you add your mass.

I think they were talking about Geoff.

No, silly, I ofc meant measuring it directly. With a pressure transducer for an example, if I calibrate it to zero sitting on my desk by itself and then for an example place the sensor head
at surface of a massive object, should the pressure reading change? Or if I attach it to a massive object, so that the sensor head is more or less flush with the surface, should I then see a change in the reading?

Let's fly past this or we are going to end up right back to square one. Try not to add things in and let's keep it as simple as possible.

I can't accept that. A sponge can 'absorb' fluids into it, but completely solid materials weigh different amounts too. When I submerge a 10cm³ solid object in a 10l bucket filled with a fluid, exactly one liter will be displaced & 9 liters will remain, completely regardless of the object's density/mass/weight.

Surely you don't believe this, do you? So a 10cm³ sponge is going to displace the same amount of water as a 10 cm³block of wood? seriously?

The reason I thought you might have a different meaning for the word displace is that I've never before heard anyone speak of pressure being displaced.

No, because it doesn't get used with atmospheric pressure. I'm using it to show you why atmospheric pressure upon an ojects density is the sole reason for a man made measurement of weight is achieved and why gravity is destro6yed by it. Denpressure.

Does this mean that the thermal energy contained by the ball is a major component in production of the force that keeps it moving after I've released it? It's not the pressure above it by itself, which is pushing the ball down, but the thermal energy and the effects of pressure equalization combined that produce a force that drives the ball up?

All you're going to do is confuse yourself more and more, unless you are doing this on purpose.
I'm willing to keep explaining but you'd better start gathering the basics and stop going off track, otherwise you will never grasp what I'm saying.

Manual kitchen scales can read minus by simply pulling up the plate, so if your digital ones can do that, then it's fine to just do your tare weight, then add your 100g and stick it in.

As I said earlier, sceptimatic obviously isn't aware of the difference between "mass" and "weight" LOL.

The forum clown is now suggesting that you can change  a 100g mass into a (say) 90g mass!

Quote from: neimoka on November 21, 2014, 11:06:10 AM

No, silly, I ofc meant measuring it directly. With a pressure transducer for an example, if I calibrate it to zero sitting on my desk by itself and then for an example place the sensor head
at surface of a massive object, should the pressure reading change? Or if I attach it to a massive object, so that the sensor head is more or less flush with the surface, should I then see a change in the reading?

Let's fly past this or we are going to end up right back to square one. Try not to add things in and let's keep it as simple as possible.

How's that? This is something we can measure and verify. But I don't know what the model predicts so the results wouldn't mean anything to me.

Quote from: neimoka on November 21, 2014, 11:06:10 AM

I can't accept that. A sponge can 'absorb' fluids into it, but completely solid materials weigh different amounts too. When I submerge a 10cm³ solid object in a 10l bucket filled with a fluid, exactly one liter will be displaced & 9 liters will remain, completely regardless of the object's density/mass/weight.

Surely you don't believe this, do you? So a 10cm³ sponge is going to displace the same amount of water as a 10 cm³block of wood? seriously?

Obviously when I said 'solid object' I meant to exclude stuff like sponges that would absorb some of the fluid. Unless you could first remove all air from the sponge and then have 1l of solid sponge left, but for simplicity let's just say one 10cm³ object is solid pvc and the other solid iron. Volumes are the same, they displace the same amount of fluid, but weight and density are very different.

Quote from: neimoka on November 21, 2014, 11:06:10 AM

The reason I thought you might have a different meaning for the word displace is that I've never before heard anyone speak of pressure being displaced.

No, because it doesn't get used with atmospheric pressure. I'm using it to show you why atmospheric pressure upon an ojects density is the sole reason for a man made measurement of weight is achieved and why gravity is destro6yed by it. Denpressure.

Sorry but using common words in unconventional meaning isn't really helpful if you intend to make a clear explanation.

Quote from: neimoka on November 21, 2014, 11:06:10 AM

Does this mean that the thermal energy contained by the ball is a major component in production of the force that keeps it moving after I've released it? It's not the pressure above it by itself, which is pushing the ball down, but the thermal energy and the effects of pressure equalization combined that produce a force that drives the ball up?

All you're going to do is confuse yourself more and more, unless you are doing this on purpose.
I'm willing to keep explaining but you'd better start gathering the basics and stop going off track, otherwise you will never grasp what I'm saying.

I'm not going off track, this is still on the subject that I don't think has been adequately explained - why a ball continues to move up after it was pushed.

Obviously when I said 'solid object' I meant to exclude stuff like sponges that would absorb some of the fluid. Unless you could first remove all air from the sponge and then have 1l of solid sponge left, but for simplicity let's just say one 10cm³ object is solid pvc and the other solid iron. Volumes are the same, they displace the same amount of fluid, but weight and density are very different.

So a 10cm³ block of plastic is going to displace the same amount of water as a 10 cm³ block of iron. Do you seriously believe this?

So a 10cm³ block of plastic is going to displace the same amount of water as a 10 cm³ block of iron. Do you seriously believe this?

LOL..... only sceptimatic could possibly not believe this!  It's all getting funnier by the day.   

Quote from: neimoka on November 21, 2014, 12:22:18 PM

Obviously when I said 'solid object' I meant to exclude stuff like sponges that would absorb some of the fluid. Unless you could first remove all air from the sponge and then have 1l of solid sponge left, but for simplicity let's just say one 10cm³ object is solid pvc and the other solid iron. Volumes are the same, they displace the same amount of fluid, but weight and density are very different.

So a 10cm³ block of plastic is going to displace the same amount of water as a 10 cm³ block of iron. Do you seriously believe this?

I can literally see it with my very own eyes when I grab a bucket and stick stuff in it, belief has nothing to do with it.

Quote from: sceptimatic on November 21, 2014, 12:28:18 PM

Quote from: neimoka on November 21, 2014, 12:22:18 PM

Obviously when I said 'solid object' I meant to exclude stuff like sponges that would absorb some of the fluid. Unless you could first remove all air from the sponge and then have 1l of solid sponge left, but for simplicity let's just say one 10cm³ object is solid pvc and the other solid iron. Volumes are the same, they displace the same amount of fluid, but weight and density are very different.

So a 10cm³ block of plastic is going to displace the same amount of water as a 10 cm³ block of iron. Do you seriously believe this?

I can literally see it with my very own eyes when I grab a bucket and stick stuff in it, belief has nothing to do with it.

Let me get this straight. You are not using any force on these two blocks, right? you are allowing each block to be put into the water to displace that water on their own, right?

Quote from: neimoka on November 21, 2014, 12:38:58 PM

Quote from: sceptimatic on November 21, 2014, 12:28:18 PM

Quote from: neimoka on November 21, 2014, 12:22:18 PM

Obviously when I said 'solid object' I meant to exclude stuff like sponges that would absorb some of the fluid. Unless you could first remove all air from the sponge and then have 1l of solid sponge left, but for simplicity let's just say one 10cm³ object is solid pvc and the other solid iron. Volumes are the same, they displace the same amount of fluid, but weight and density are very different.

So a 10cm³ block of plastic is going to displace the same amount of water as a 10 cm³ block of iron. Do you seriously believe this?

I can literally see it with my very own eyes when I grab a bucket and stick stuff in it, belief has nothing to do with it.

Let me get this straight. You are not using any force on tehse two blocks, right? you are allowing each block to be put into the water to displace that water on their own, right?

Correct.

earlier I used 10cm³ interchangeably with 1l, this is ofc incorrect. One liter is 1000³, not really relevant but there it is.

Quote from: sceptimatic on November 21, 2014, 12:42:02 PM

Quote from: neimoka on November 21, 2014, 12:38:58 PM

Quote from: sceptimatic on November 21, 2014, 12:28:18 PM

Quote from: neimoka on November 21, 2014, 12:22:18 PM

Obviously when I said 'solid object' I meant to exclude stuff like sponges that would absorb some of the fluid. Unless you could first remove all air from the sponge and then have 1l of solid sponge left, but for simplicity let's just say one 10cm³ object is solid pvc and the other solid iron. Volumes are the same, they displace the same amount of fluid, but weight and density are very different.

So a 10cm³ block of plastic is going to displace the same amount of water as a 10 cm³ block of iron. Do you seriously believe this?

I can literally see it with my very own eyes when I grab a bucket and stick stuff in it, belief has nothing to do with it.

Let me get this straight. You are not using any force on tehse two blocks, right? you are allowing each block to be put into the water to displace that water on their own, right?

Correct.

earlier I used 10cm³ interchangeably with 1l, this is ofc incorrect. One liter is 1000³, not really relevant but there it is.

so your pvc block was dropped into the water and it displaced exactly the same amount of water as your iron block dropped into the water, without you applying any pressure to push down the pvc block, right?

sceptimatic's never heard of Archimedes apparently?   

Quote from: neimoka on November 21, 2014, 12:44:26 PM

Quote from: sceptimatic on November 21, 2014, 12:42:02 PM

Quote from: neimoka on November 21, 2014, 12:38:58 PM

Quote from: sceptimatic on November 21, 2014, 12:28:18 PM

Quote from: neimoka on November 21, 2014, 12:22:18 PM

Obviously when I said 'solid object' I meant to exclude stuff like sponges that would absorb some of the fluid. Unless you could first remove all air from the sponge and then have 1l of solid sponge left, but for simplicity let's just say one 10cm³ object is solid pvc and the other solid iron. Volumes are the same, they displace the same amount of fluid, but weight and density are very different.

So a 10cm³ block of plastic is going to displace the same amount of water as a 10 cm³ block of iron. Do you seriously believe this?

I can literally see it with my very own eyes when I grab a bucket and stick stuff in it, belief has nothing to do with it.

Let me get this straight. You are not using any force on tehse two blocks, right? you are allowing each block to be put into the water to displace that water on their own, right?

Correct.

earlier I used 10cm³ interchangeably with 1l, this is ofc incorrect. One liter is 1000³, not really relevant but there it is.

so your pvc block was dropped into the water and it displaced exactly the same amount of water as your iron block dropped into the water, without you applying any pressure to push down the pvc block, right?

That would be the idea, but just to be clear that pvc block was just an example, not an account of what I'd have just done. Anyway the principle applies. It may be tricky to find suitable objects of different weight but precisely identical dimensions (volume) in a household but I'm sure you can come up with something if you want to try it. What kind of precision would be required to satisfy you in an experiment like this? When I get to work I can scavenge and cut up various materials to size, steel and rubbers/plastics, will submerging them in a normal measuring cup such as used in the laboratory or kitchen be sufficient? That would be extremely easy to do. Naturally you will need to repeat the experiment yourself.

That would be the idea, but just to be clear that pvc block was just an example, not an account of what I'd have just done. Anyway the principle applies. It may be tricky to find suitable objects of different weight but precisely identical dimensions (volume) in a household but I'm sure you can come up with something if you want to try it. What kind of precision would be required to satisfy you in an experiment like this? When I get to work I can scavenge and cut up various materials to size, steel and rubbers/plastics, will submerging them in a normal measuring cup such as used in the laboratory or kitchen be sufficient? That would be extremely easy to do. Naturally you will need to repeat the experiment yourself.

I know we are dealing with atmospheric pressure upon an objects density and I'm showing you why water is going to prove what I'm saying.
I'd like you to pay absolute attention to what I type out. I'm not trying to be clever or anything. I'm being serious, ok?

The reason why I asked you about the pvc and the iron block was for very good reason and also as to why you cannot use a bucket to gain a true reflection of what I'm trying to explain with other similar sized sinkable objects.

I will do it one step at a time so we don't lose track. Are you up to observing and absorbing what I say? If you are, I will be back on later to show you why it all equates to what I'm saying and you might just grasp it all. Fair enough?

When I get to work I can scavenge and cut up various materials to size, steel and rubbers/plastics, will submerging them in a normal measuring cup such as used in the laboratory or kitchen be sufficient? That would be extremely easy to do. Naturally you will need to repeat the experiment yourself.

How about a 100cm³ block of iron, and a 100cm³ block of hardwood, such as Desert Ironwood with a density of 1,208 kg/m³.  Ironwood is a fairly common hobbyist's timber.

I will do it one step at a time so we don't lose track. Are you up to observing and absorbing what I say? If you are, I will be back on later to show you why it all equates to what I'm saying and you might just grasp it all. Fair enough?

I'm guessing sceptimatic must be a failed kindergarten teacher?   

Scepti is being deliberately obtuse and not mentioning the fact that the PVC pipe would ve buoyant. We would need 2 objects with the same buoyancy of different densities and the same volumes.

Scepti is being deliberately obtuse and not mentioning the fact that the PVC pipe would ve buoyant. We would need 2 objects with the same buoyancy of different densities and the same volumes.

Thats giving him a lot of credit. He also could have just not known that.

Quote from: rottingroom on November 21, 2014, 01:10:32 PM

Scepti is being deliberately obtuse and not mentioning the fact that the PVC pipe would ve buoyant. We would need 2 objects with the same buoyancy of different densities and the same volumes.

Thats giving him a lot of credit. He also could have just not known that.

Scepti isn't as stupid as he makes himself out to be. He deliberately constructs what he says in ways that he can say "I didn't say that" later. You'll see.

Quote from: neimoka on November 21, 2014, 12:56:06 PM

That would be the idea, but just to be clear that pvc block was just an example, not an account of what I'd have just done. Anyway the principle applies. It may be tricky to find suitable objects of different weight but precisely identical dimensions (volume) in a household but I'm sure you can come up with something if you want to try it. What kind of precision would be required to satisfy you in an experiment like this? When I get to work I can scavenge and cut up various materials to size, steel and rubbers/plastics, will submerging them in a normal measuring cup such as used in the laboratory or kitchen be sufficient? That would be extremely easy to do. Naturally you will need to repeat the experiment yourself.

I know we are dealing with atmospheric pressure upon an objects density and I'm showing you why water is going to prove what I'm saying.
I'd like you to pay absolute attention to what I type out. I'm not trying to be clever or anything. I'm being serious, ok?

The reason why I asked you about the pvc and the iron block was for very good reason and also as to why you cannot use a bucket to gain a true reflection of what I'm trying to explain with other similar sized sinkable objects.

I will do it one step at a time so we don't lose track. Are you up to observing and absorbing what I say? If you are, I will be back on later to show you why it all equates to what I'm saying and you might just grasp it all. Fair enough?

I can't see why I'd be more likely to lose track if it was just one post, if it's split up there are distractions in between with other people posting on the topic, quotes tend to get lost when they get too long and so on, I must have skipped and forgotten half of the details and points of argument I've had on my mind during this exchange just because of this. So I'd prefer if it wasn't necessary to go step by step. I read books for fun, I think I can take one forum post - as long as it's concise, to the point and not by Sandokhan.

If you think that submerging an object in a measuring cup with fluid in it isn't descriptive of how much fluid an object displaces (!?) perhaps you could suggest another experiment?

I'm very interested in how pvc is special in this regard.

(density of polyvinyl chloride is well over 1 g/cm³, there is variance in products but generally it actually does sink)

Quote from: Lemmiwinks on November 21, 2014, 01:13:37 PM

Quote from: rottingroom on November 21, 2014, 01:10:32 PM

Scepti is being deliberately obtuse and not mentioning the fact that the PVC pipe would ve buoyant. We would need 2 objects with the same buoyancy of different densities and the same volumes.

Thats giving him a lot of credit. He also could have just not known that.

Scepti isn't as stupid as he makes himself out to be. He deliberately constructs what he says in ways that he can say "I didn't say that" later. You'll see.

Why do you guys think I'm asking so many specific questions?? 

Scepti isn't as stupid as he makes himself out to be. He deliberately constructs what he says in ways that he can say "I didn't say that" later. You'll see.

I'm sorry, but I beg to differ.  sceptimatic is actually more stupid than he makes out.   

Quote from: rottingroom on November 21, 2014, 01:24:53 PM

Scepti isn't as stupid as he makes himself out to be. He deliberately constructs what he says in ways that he can say "I didn't say that" later. You'll see.

I'm sorry, but I beg to differ.  sceptimatic is actually more stupid than he makes out.   

Geoffrey you can't even tell when someone is telling you to shut up. Subtlety is not your forte.

Scepti is being deliberately obtuse and not mentioning the fact that the PVC pipe would ve buoyant. We would need 2 objects with the same buoyancy of different densities and the same volumes.

Buoyancy is going to be the same if volumes are the same, right? They just need to have enough weight to overcome that. Ofc both objects should sink, much easier to eyeball displacement that way.

Quote from: rottingroom on November 21, 2014, 01:10:32 PM

Scepti is being deliberately obtuse and not mentioning the fact that the PVC pipe would ve buoyant. We would need 2 objects with the same buoyancy of different densities and the same volumes.

Buoyancy is going to be the same if volumes are the same, right? They just need to have enough weight to overcome that. Ofc both objects should sink, much easier to eyeball displacement that way.

Well these are exactly the type of questions scepti likes to mess with people on. You didn't specify if the blocks were hollow. When you first mentioned a 10 cm^3 block of plastic, I imagined that it would be hollow and when you first mentioned the 10 cm^3 block of iron I imagined that it wasn't and I have a feeling that is also what scepti was thinking. This is why he was asking you if you would have to apply force to them... The iron block would sink and the pvc block wouldn't, therefore the iron block would displace more water. If you don't get very specific he will do this.

For example, in the past he has said he is has 13 camera's and is a professional. He never said he was a professional photographer and people keep on accusing him of saying he is. So then he goes onto say, "show me where I've said I'm a professional photographer".

This is the type of thing he does.

Quote from: neimoka on November 21, 2014, 01:50:58 PM

Quote from: rottingroom on November 21, 2014, 01:10:32 PM

Scepti is being deliberately obtuse and not mentioning the fact that the PVC pipe would ve buoyant. We would need 2 objects with the same buoyancy of different densities and the same volumes.

Buoyancy is going to be the same if volumes are the same, right? They just need to have enough weight to overcome that. Ofc both objects should sink, much easier to eyeball displacement that way.

Well these are exactly the type of questions scepti likes to mess with people on. You didn't specify if the blocks were hollow. When you first mentioned a 10 cm^3 block of plastic, I imagined that it would be hollow and when you first mentioned the 10 cm^3 block of iron I imagined that it wasn't and I have a feeling that is also what scepti was thinking. This is why he was asking you if you would have to apply force to them... The iron block would sink and the pvc block wouldn't, therefore the iron block would displace more water. If you don't get very specific he will do this.

For example, in the past he has said he is has 13 camera's and is a professional. He never said he was a professional photographer and people keep on accusing him of saying he is. So then he goes onto say, "show me where I've said I'm a professional photographer".

This is the type of thing he does.

I did say 'solid objects'... well maybe it should have been 'non-hollow solid objects' :p I also specifically said that they would be submerged, so it wouldn't actually even matter if one was hollow, it still displaces the same amount of water or any fluid.

At least he made it clear that he believes that 10 cm^3 of plastic would not displace just as much water as 10 cm^3 of iron, we'll see how his explanation for that unfolds