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EmiliaM wrote:So I just came across an experiment, and have had similar ones in the past, using 4 different types of materials where the topic is absorbency. We had limited measuring devices: only the stopwatch and ruler we can use in competitions. My initial thoughts were doing something like porosity vs amount of water absorbed, or density vs amount of water absorbed. However there would be no way to measure porosity and density with the experiment given, so I would do something for the IV like: low density, medium density, and high density, and the experiment would use a bar graph. Is this even allowed since we couldn’t measure density and only used qualititative observations to determine this? Also what would the SOC be? Any ideas on this, and also for a better experiment idea with this topic?

hmm... I've seen prompts like these and sometimes there's just no way around using qualitative levels for the IV. there shouldn't be any points taken off for having a bar graph since the rubric calls for "appropriate type of graph used", though you'd probably lose points in the "IV operationally defined" criterion.

I personally wouldn't use density or porosity as independent variables since they're more difficult to estimate qualitatively. it might be more suitable to use thickness of the material or just use one material altogether and simply vary its area/size quantitatively.

my teammates and I usually refer to the extreme minimum IV level when it doesn't make any logical sense to have a SOC of 0, otherwise we just use a zero level. reasoning is usually something along the lines of it being a baseline level to compare with future levels that are manipulated, so in your case, I'd go with the lowest density material.

as for other experiment ideas:
> time taken a single drop of water to absorb into different materials. time is probably more easy to measure in these types of experiments since measuring the amount of water absorbed can be difficult when the water makes a huge blob :^)
> something relating to length/surface area of the material and time to absorb completely? this one might be a stretch for relating to absorbency but on the plus side both the IV and DV would be able to be measured quantitatively.

Oh... I placed at nats in this event.

bromothymol wrote:

EmiliaM wrote:So I just came across an experiment, and have had similar ones in the past, using 4 different types of materials where the topic is absorbency. We had limited measuring devices: only the stopwatch and ruler we can use in competitions. My initial thoughts were doing something like porosity vs amount of water absorbed, or density vs amount of water absorbed. However there would be no way to measure porosity and density with the experiment given, so I would do something for the IV like: low density, medium density, and high density, and the experiment would use a bar graph. Is this even allowed since we couldn’t measure density and only used qualititative observations to determine this? Also what would the SOC be? Any ideas on this, and also for a better experiment idea with this topic?

hmm... I've seen prompts like these and sometimes there's just no way around using qualitative levels for the IV. there shouldn't be any points taken off for having a bar graph since the rubric calls for "appropriate type of graph used", though you'd probably lose points in the "IV operationally defined" criterion.

I personally wouldn't use density or porosity as independent variables since they're more difficult to estimate qualitatively. it might be more suitable to use thickness of the material or just use one material altogether and simply vary its area/size quantitatively.

my teammates and I usually refer to the extreme minimum IV level when it doesn't make any logical sense to have a SOC of 0, otherwise we just use a zero level. reasoning is usually something along the lines of it being a baseline level to compare with future levels that are manipulated, so in your case, I'd go with the lowest density material.

as for other experiment ideas:
> time taken a single drop of water to absorb into different materials. time is probably more easy to measure in these types of experiments since measuring the amount of water absorbed can be difficult when the water makes a huge blob :^)
> something relating to length/surface area of the material and time to absorb completely? this one might be a stretch for relating to absorbency but on the plus side both the IV and DV would be able to be measured quantitatively.

Thank you so much!!

EmiliaM wrote:So I just came across an experiment, and have had similar ones in the past, using 4 different types of materials where the topic is absorbency. We had limited measuring devices: only the stopwatch and ruler we can use in competitions. My initial thoughts were doing something like porosity vs amount of water absorbed, or density vs amount of water absorbed. However there would be no way to measure porosity and density with the experiment given, so I would do something for the IV like: low density, medium density, and high density, and the experiment would use a bar graph. Is this even allowed since we couldn’t measure density and only used qualititative observations to determine this? Also what would the SOC be? Any ideas on this, and also for a better experiment idea with this topic?

I would make the dependent variable amount of water absorbed, for sure. The Independent variable could be something qualitative like material, but you would have rising levels of density.

How does the polarity of salt dissolved in water change if the concentration of salt increases? *in context of experimental prompt regarding properties of better (more specifically paper towel chromatography)

Does anyone actually know the rules regarding counts? For example, if I was measuring the period of a spring, and I timed five iterations of the spring (a unit that would be considered “count”) as maybe 1.56 seconds, what would I report as the average time for a period? 0.3? 0.31?0.312?

TheWood wrote:Does anyone actually know the rules regarding counts? For example, if I was measuring the period of a spring, and I timed five iterations of the spring (a unit that would be considered “count”) as maybe 1.56 seconds, what would I report as the average time for a period? 0.3? 0.31?0.312?

I would argue that finding the average is a calculation done to the data, therefore it is based upon the significant figures of the input(s). In your example, the only input would be 1.56, which has three significant figures. Thus the average should as well.

nicholasmaurer wrote:

TheWood wrote:Does anyone actually know the rules regarding counts? For example, if I was measuring the period of a spring, and I timed five iterations of the spring (a unit that would be considered “count”) as maybe 1.56 seconds, what would I report as the average time for a period? 0.3? 0.31?0.312?

I would argue that finding the average is a calculation done to the data, therefore it is based upon the significant figures of the input(s). In your example, the only input would be 1.56, which has three significant figures. Thus the average should as well.

Lets say that your data was:
IV1: 6.54s,6.98s,7.01s
IV2:8.97s,8.56s,9.13s
IV3:11.56s,11.95s,11.14s
the signicant figures used in IV3 is 3, while IV1 an IV2 uses 3 significant figures, is this alright? There is nothing I can do about it because that is just what my stop watch tells me. Would I add an extra 0 for IV1 and IV2 just so all trials for all IV would use the same amount of significant figures or just leave it as is?

terence.tan wrote:

nicholasmaurer wrote:

TheWood wrote:Does anyone actually know the rules regarding counts? For example, if I was measuring the period of a spring, and I timed five iterations of the spring (a unit that would be considered “count”) as maybe 1.56 seconds, what would I report as the average time for a period? 0.3? 0.31?0.312?

I would argue that finding the average is a calculation done to the data, therefore it is based upon the significant figures of the input(s). In your example, the only input would be 1.56, which has three significant figures. Thus the average should as well.

Lets say that your data was:
IV1: 6.54s,6.98s,7.01s
IV2:8.97s,8.56s,9.13s
IV3:11.56s,11.95s,11.14s
the signicant figures used in IV3 is 3, while IV1 an IV2 uses 3 significant figures, is this alright? There is nothing I can do about it because that is just what my stop watch tells me. Would I add an extra 0 for IV1 and IV2 just so all trials for all IV would use the same amount of significant figures or just leave it as is?

I think you mean to say IV3 has four significant figures, while IV1 and IV2 have three. You should NOT add extra significant figures to your raw data for IV1 and IV2 - your instrument does not report time to that level of precision. You would leave your data as reported. If you performed calculations using IV3, they would have an additional significant figure as compared to calculations done with IV1 or IV2.

How would you indicate one sig fig for zero? 0 or 0.?