More than one Experiment within One Project OK?

[lisagrady]

My son't project is up and running and now his teacher (new to science fair) is questioning having "too many variables". He wanted this to be a comparison and complex test and set up 3 controlled experiments. WIthin each of these experiments he has the same one Responding and one Dependent Variables. The controls for all of the 3 experiments are the same except for the construction materials. We tried explaining this is One Science Project that has a total of 3 Controlled Experiments each with their own set of Variables (which happen to be the same except in construction). To make it more clear, he constructed a Residential Village. Experiment 1 is 2 Wood Frame Houses with Wood Roofs. Experiment 2 is 2 Wood Frame Houses with Tin Roofs, Experiment 3 is 2 Concrete Block House with Wood Roof. In each of these experiments one of the houses is "coated" with a special product and the other is not. In each of these experiments the interior cubic area is the same. His project is questioning whether the "coated" houses are more energy efficient than the noncoated houses (and by how much) AND which of these 3 construction methods are the most energy efficient when comparing all 3. His project has a purpose because his brother is trying to build a barn for his rabbits and wants it to stay warm in the winter and cool in the summer (our bigger problem in Florida).

We had read a lot before starting this and found that this is more than the judges require but as long as each experiment was done using Scientific Method this was OK?

Can anyone confirm and add comments. It is still possible to tweak this if it does not fall within guidelines but it will look very very simplistic when it is actually quiet complex and involved a lot of research into nanotechnology on his part.

Thanks,

Mom

[deleted-71762]

Dear Mom,

I can see where the teacher would think the experiment could get derailed and lose focus. The typical science fair project investigates one dependent variable https://www.sciencebuddies.org/mentorin ... bles.shtml; however, having said that, I think there is merit in continuing with the dual variable approach with a slight twist that, to me, would make the experiment easier to follow and save you guys time. Instead of building six structures (2 of each) one with and one without a coating, I suggest the following:

1. Build one of each type, one wood/wood, one wood/tin, one concrete/wood. Evaluate the designs with "Method of Construction" being the independent variable and temperature being the dependent variable.
2. Determine which structure in Part 1 supports the hypothesis (you may need to choose the bigger of your problems....Hot Summer or Cool Winter as the best design for Summer may not be the best design for Winter)

3. Peform a Part 2 of your experiment where you take the winning design from Part 1 and then paint it with the coating and use the "structure's optical property (Color)" as the independent variable and temperature again as a dependent variable.... as if you're optimizing your winning design from Part I. Then see how the best design from Part I performs with and without a coating.

I think this makes for a cleaner and easier experiment.

Make sure you use the same area on all external walls and roof (i.e. 1 ft x 1ft, 1ft) with the same interior volume and place the structures far enough apart so that one does not have an affect on the other. In addition make sure they're seeing the same relative environment so that, for example, one may be shaded by a tree while the other two are not. This will make sure your control variables are the same.


Best of Luck,

Marc

[lisagrady]

OK thanks for the idea. We have built 4 of the 6 structures already, but maybe this might be a better idea. Thanks for suggesting this. We have considered the spacing and environment and have them in an open sunny backyard on the same ground surface, so I think that one is definitely controlled. We are finishing the construction up this week and I was not looking forward to the messy concrete ones we have left so maybe building one and having a contest is the best idea.

Thanks again for the suggestion. I will let you know what Mr. Hard-Head (aka my son) thinks about this. Wish I would have thought about that before I bought 6 thermometers too.

Mom

[deleted-71762]

Dear Mom,

Sounds like you guys are on the right path. I would seriously consider the two pronged approach especially as the concrete could then be painted with a coating if it is the clear winning design (you may want to also consider a concrete structure with a tin roof ). If it helps to persuade your son, I do thermal analysis on Spacecraft for a living....this is the way I would go about evaluating spacecraft designs.

Best regards,

Marc

[lisagrady]

OK we are exhausted. Building the concrete house was a bear and still wet of course. So after talking while we were working we have decided to go with one of the experiments. I guess all our work and building 6 structures is for nothing! (Or maybe he will figure out some way to use in a continuation project next year). Anyway, we decided to go with the Wood Frame building with the tin roof since this is more like an actual barn on a farm would be constructed (his real world application).

Our new question is this....we need some very fast data to hand in to the teacher by December 4 (she said we can then take out time to collect data before regional competition in February). Our structures are 2x2x2 and there are 2 of them. We can not rely on data from the outside temperature alone at this point because we do not have enough significant variation this time of year in Florida. For the "heated" portion of the experiment my son came up with one room in our house that has its own AC system. The temp could be turned up high and temp inside both coated/noncoated houses recorded at different times. WHAT ABOUT COLD TEMPERATURES? Anyone have any ideas how we could locate these structures somewhere at extremely cold temperatures so we could record data? I was thinking about a walk in freezer but do not even know who to ask about something like this. The thermostat in that one room in our house would probably only drop the temperature to 68 or so at a minimum and he is looking for lower temperatures than that. I am not aware of any rentable chillers of any kind. DOES ANYONE HAVE ANY IDEAS?

[lisagrady]

CONTINUATION OF PRIOR POST RE: MORE THAN ONE CONTROLLED EXPERIMENT:

OK we are exhausted. Building the concrete house was a bear and still wet of course. So after talking while we were working we have decided to go with one of the experiments. I guess all our work and building 6 structures is for nothing! (Or maybe he will figure out some way to use in a continuation project next year). Anyway, we decided to go with the Wood Frame building with the tin roof since this is more like an actual barn on a farm would be constructed (his real world application).

Our new question is this....we need some very fast data to hand in to the teacher by December 4 (she said we can then take out time to collect data before regional competition in February). Our structures are 2x2x2 and there are 2 of them. We can not rely on data from the outside temperature alone at this point because we do not have enough significant variation this time of year in Florida. For the "heated" portion of the experiment my son came up with one room in our house that has its own AC system. The temp could be turned up high and temp inside both coated/noncoated houses recorded at different times. WHAT ABOUT COLD TEMPERATURES? Anyone have any ideas how we could locate these structures somewhere at extremely cold temperatures so we could record data? I was thinking about a walk in freezer but do not even know who to ask about something like this. The thermostat in that one room in our house would probably only drop the temperature to 68 or so at a minimum and he is looking for lower temperatures than that. I am not aware of any rentable chillers of any kind. DOES ANYONE HAVE ANY IDEAS?

My son just came in and said "How about we take our buildings to the Ice Skating Rink"? Can any of you from up North answer this question? Would an ice skating rink indoor temp be in about the 40 degree range? (I know the ice is below this duh) I am talking ambient temperature of the arena/rink? It always seems cold (but then again we have been 2 or 3 times in our lives).

Open to all suggestions.

[deleted-71588]

Try thinking about the problem differently. You are trying to measure thermal transfer between the inside and the outside of the structures. Unless there is some material that changes state in the structure or in the inside or outside ambient air, temperature difference is temperature difference. You found a way to raise the outside ambient temperature. Instead of trying to find a way to cool the outside ambient temperature, why not simply increase the inside ambient temperature? A 40w to 200w tungsten light bulb in a ceramic fixture (so you don't exceed its temperature ratings and melt it) should be able to easily raise the inside temperature of 4 cubic feet by various amounts.

You might want to consider the effect of wind on the thermal transfer as well by using a fan. The coating material might make a significant difference to convection transfers and air infiltration that will show up.

By not testing at lower temperatures, you won't be able to evaluate any moisture barrier / condensation issues. Given the short amount of time you have to complete the initial experiments, that sounds like a great compromise.

[deleted-71588]

See my answers in your other thread.

[MelissaB]

I have gone ahead and merged the posts; it helps us experts to have some background to the problem .

[deleted-71762]

I agree with Craig. The main idea to note here is temperature difference. Ideally, you want an extreme cold environment and extreme hot environment. However, say in spacecraft testing, we have to fabricate those environments using cryogenics to mimic the extreme cold of outer space. Yes, a skating rink should be colder due to the mass of the ice radiating into the building but it does not represent the physical location of where you're trying to use this structure...in a backyard or farm...thus you're missing out on the Natural Environments (Sun, clouds, night sky, etc). My suggestion is to simply revert back to the comfort of your back yard. Measure the ambient temperature outside, and the ambient temperature in the building (at specific time intervals, i.e. 12, 3, 6, 9,12am, etc) Extreme cold for you may end up being in the 50s or 60s in Florida. Don't worry....what matters is the diffrence in temperature. If one structure is 5 degrees warmer and another is only 2 degrees warmer than the outside temperature....then you know that the 5 has better insulating properties or less heat transfer to the outside. To me it's just a matter of rolling up your sleeves and getting that data this week.

Hope this helps!

Best of luck,

Marc