Testing the electrical conductivity of substancs (1 Viewer)

[jathu123]

So I'm gonna have a prac assessment on testing the electrical conductivity of some substances (second dot point on chemical earth). So I have a few questions and I'm terrible on electrical stuff, would really appreciate if anyone could help me out.

1. Does it matter where I place my ammeter, both in circuit drawings and the prac? I was thinking of putting it after the testing material, since the ammeter could measure if any current has been passed through the material. If this is true, then which way does the current flow (so I could draw the ammeter)

2. We're also supposed to construct a table to record the data. I was thinking of having the subheadings; Substance name | metal, metalloid, or semimetal? | Amperes (A) | Conductivity (S/m) |

Are the units for the conductivity correct? ie. Siemens/meter, s/m? And this is the inverse of the resistance right, so basically to calculate this, I would just need to divide the Amperes by the voltage right?

Thankyou so much for answering these questions

 

[Nailgun]

So I'm gonna have a prac assessment on testing the electrical conductivity of some substances (second dot point on chemical earth). So I have a few questions and I'm terrible on electrical stuff, would really appreciate if anyone could help me out.

1. Does it matter where I place my ammeter, both in circuit drawings and the prac? I was thinking of putting it after the testing material, since the ammeter could measure if any current has been passed through the material. If this is true, then which way does the current flow (so I could draw the ammeter)

2. We're also supposed to construct a table to record the data. I was thinking of having the subheadings; Substance name | metal, metalloid, or semimetal? | Amperes (A) | Conductivity (S/m) |

Are the units for the conductivity correct? ie. Siemens/meter, s/m? And this is the inverse of the resistance right, so basically to calculate this, I would just need to divide the Amperes by the voltage right?

Thankyou so much for answering these questions

1. Doesn't matter where the ammeter goes as it is in series. If you think about it, the current is continually flowing through circuit over and over again so even if it's 'after' the material this makes a difference for like a fraction of a second lol. Current flows from in real life from negative to positive, however in convention current it flows from positive to negative lol. I think on your diagrams show it as conventional current, but when you do it keep in mind that it actually goes from negative to positive.

2. That sounds fine to me

3. Not sure lol, a quick look on wikipedia has me thinking it's either just siemens or siemens/meter so I'll let someone else confirm this.

 

[InteGrand]

So I'm gonna have a prac assessment on testing the electrical conductivity of some substances (second dot point on chemical earth). So I have a few questions and I'm terrible on electrical stuff, would really appreciate if anyone could help me out.

1. Does it matter where I place my ammeter, both in circuit drawings and the prac? I was thinking of putting it after the testing material, since the ammeter could measure if any current has been passed through the material. If this is true, then which way does the current flow (so I could draw the ammeter)

2. We're also supposed to construct a table to record the data. I was thinking of having the subheadings; Substance name | metal, metalloid, or semimetal? | Amperes (A) | Conductivity (S/m) |

Are the units for the conductivity correct? ie. Siemens/meter, s/m? And this is the inverse of the resistance right, so basically to calculate this, I would just need to divide the Amperes by the voltage right?

Thankyou so much for answering these questions

 

[InteGrand]

So yes, if you want to calculate the conductance for your piece of metal, it's just the current divided by the voltage (so the technically correct thing to do is write 'conductance' for the table heading). Here are some useful links with more info if you're curious:

• https://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity (Resistivity and Conductivity; go to the 'Definition' section to see the defining equations and a diagram)

• https://en.wikipedia.org/wiki/Electrical_resistance_and_conductance (Resistance and Conductance)

 

[Nailgun]

So I'm gonna have a prac assessment on testing the electrical conductivity of some substances (second dot point on chemical earth). So I have a few questions and I'm terrible on electrical stuff, would really appreciate if anyone could help me out.

1. Does it matter where I place my ammeter, both in circuit drawings and the prac? I was thinking of putting it after the testing material, since the ammeter could measure if any current has been passed through the material. If this is true, then which way does the current flow (so I could draw the ammeter)

2. We're also supposed to construct a table to record the data. I was thinking of having the subheadings; Substance name | metal, metalloid, or semimetal? | Amperes (A) | Conductivity (S/m) |

Are the units for the conductivity correct? ie. Siemens/meter, s/m? And this is the inverse of the resistance right, so basically to calculate this, I would just need to divide the Amperes by the voltage right?

Thankyou so much for answering these questions

Oh yeah, this is kind of random but make sure that you rule up the table fully, like close off every cell, column and row. Don't just draw a horizontal line to separate the headings, and a couple vertical lines to separate the columns. Make sure everything is fully boxed ahahah

 

[jathu123]

ohh, thanks InteGrand. Didn't even know that there was a difference between conductivity and conductance till now haha. Also, if you don't mind, do you think that ill get marks if I write up conductance and did current/voltage (instead of conductivity) in the table. Cause i don't think ill have enough tim to measure the length, area, etc. and also it does say '.. to measure conductivity of substances in the prac notification sheet. Or should I just forget about this and finish up the table with the ampere measurement?

Again, thankyou very much for that clarification

 

[jathu123]

Oh yeah, this is kind of random but make sure that you rule up the table fully, like close off every cell, column and row. Don't just draw a horizontal line to separate the headings, and a couple vertical lines to separate the columns. Make sure everything is fully boxed ahahah

haha yeah thanks for that man. My teacher already gave me like dozens of rules when drawing up tables and circuits haha

 

[leehuan]

Additionally:
1. Provided you're not interested in circuits in parallel (in series is fine), the ammeter goes anywhere.

Now, can you please remind me what dot point this was again in chemistry? I do not recall this.

 

[jathu123]

Additionally:
1. Provided you're not interested in circuits in parallel (in series is fine), the ammeter goes anywhere.

Now, can you please remind me what dot point this was again in chemistry? I do not recall this.

it's the second dot point in the chemical earth prelim chem.

'plan and perform an investigation to examine some physical properties, including malleability, hardness and electrical conductivity, and some uses of a range of common elements to present information about the classification of elements as metals, non-metals or semimetals
 analyse information from secondary sources to distinguish the physical properties of metals and non-metals
 process information from secondary sources and use a Periodic Table to
present information about the classification of elements as: – metals, non-metals and semimetals
– solids, liquids and gases at 25˚C and normal atmospheric pressure'

 

[InteGrand]

Additionally:
1. Provided you're not interested in circuits in parallel (in series is fine), the ammeter goes anywhere.

Now, can you please remind me what dot point this was again in chemistry? I do not recall this.

He said it's the ''second dot point on chemical earth''.

Edit: said above

 

[InteGrand]

ohh, thanks InteGrand. Didn't even know that there was a difference between conductivity and conductance till now haha. Also, if you don't mind, do you think that ill get marks if I write up conductance and did current/voltage (instead of conductivity) in the table. Cause i don't think ill have enough tim to measure the length, area, etc. and also it does say '.. to measure conductivity of substances in the prac notification sheet. Or should I just forget about this and finish up the table with the ampere measurement?

Again, thankyou very much for that clarification

Wait, so you actually need to measure conductivity? You'd need to measure the area and length then, which would be easy to screw up probably. If you have time, you should probably ask your teacher. Did your teacher say to use current divided by voltage? If so, they were telling you to calculate conductance without perhaps consciously knowing of the fact that it is actually conductance and not conductivity. In this case, I'd write conductance in the table and write as a note somewhere the difference between conductance and conductivity, and explain that what we calculated in the experiment is properly called 'conductance'.

(Incidentally, we probably wouldn't actually 'measure' conductance or conductivity, but rather would calculate it from other measured quantities, like voltage, current, etc.)

 

[Nailgun]

it's the second dot point in the chemical earth prelim chem.

'plan and perform an investigation to examine some physical properties, including malleability, hardness and electrical conductivity, and some uses of a range of common elements to present information about the classification of elements as metals, non-metals or semimetals
 analyse information from secondary sources to distinguish the physical properties of metals and non-metals
 process information from secondary sources and use a Periodic Table to
present information about the classification of elements as: – metals, non-metals and semimetals
– solids, liquids and gases at 25˚C and normal atmospheric pressure'

LOL now that I think about it, I think for this prac all we did to 'test' conductivity was put it into a circuit with a lightbulb in it. If the light bulb lit up, it was 'conductive', if not, then 'non-conductive'

i had a turrible teacher for prelim chem

chem sucks

 

[Shuuya]

LOL now that I think about it, I think for this prac all we did to 'test' conductivity was put it into a circuit with a lightbulb in it. If the light bulb lit up, it was 'conductive', if not, then 'non-conductive'

i had a turrible teacher for prelim chem

chem sucks

That's what we did too haha

 

[jathu123]

Wait, so you actually need to measure conductivity? You'd need to measure the area and length then, which would be easy to screw up probably. If you have time, you should probably ask your teacher. Did your teacher say to use current divided by voltage? If so, they were telling you to calculate conductance without perhaps consciously knowing of the fact that it is actually conductance and not conductivity. In this case, I'd write conductance in the table and write as a note somewhere the difference between conductance and conductivity, and explain that what we calculated in the experiment is properly called 'conductance'.

(Incidentally, we probably wouldn't actually 'measure' conductance or conductivity, but rather would calculate it from other measured quantities, like voltage, current, etc.)

Our teacher just told us to 'measure the conductivity' and gave us literally no information on what to do and told us to research every bits by ourselves, that's why this is so confusing. So yeah, ill talk to her and hopefully get this thing figured out. Thanks for your help

 

[jathu123]

LOL now that I think about it, I think for this prac all we did to 'test' conductivity was put it into a circuit with a lightbulb in it. If the light bulb lit up, it was 'conductive', if not, then 'non-conductive'

i had a turrible teacher for prelim chem

chem sucks

yeah man I was actually thinking that we would get a globe and just need to write whether its conductive or not. But when we got the notification, it had no globe, but just an ammeter. So I think we gotta measure and calculate and stuff, or just write out the ampere reading. so confusing

 

[leehuan]

it's the second dot point in the chemical earth prelim chem.

'plan and perform an investigation to examine some physical properties, including malleability, hardness and electrical conductivity, and some uses of a range of common elements to present information about the classification of elements as metals, non-metals or semimetals
 analyse information from secondary sources to distinguish the physical properties of metals and non-metals
 process information from secondary sources and use a Periodic Table to
present information about the classification of elements as: – metals, non-metals and semimetals
– solids, liquids and gases at 25˚C and normal atmospheric pressure'

We never had to classify them so extensively. We just said conductive or not. No quantitative analysis was required.

How we knew it was conductive? Same way as you. The light bulb