Physical Science

[cwaring]

Can someone please help. My daughter is doing an experiment on the Buoyancy of Floating Cylinders. The experiment calls for wooden dowels in differing sizes to be put in water with food coloring to float for several hours so that a line appears and tilt angle can be measured. All 25 dowels, all sizes came out without a pure line if anything. Very jagged markings or straight line all the way across. It seems that the dowels soaked up all color throughout the whole dowel. Is this typical and she can continue with a "no results" project?

Help much appreciated,

Thanks!

Cheri Waring

[deleted-71447]

Hi Cheri,

It is typical to run into these sorts of problems when doing an experiment. Have you tried using a stronger dye and floating the dowels for a shorter amount of time?
If you have a link to the experimental procedure or can cut and paste it into a post, that would be helpful for us to figure out what might have gone wrong.

Chris

[deleted-71727]

Cheri,

There are several reasons that you could have dowels with no line. First, it is possible that the dowel rods which you are using are a very soft would which would absorb the water like a sponge. Soft woods do this very well ... to the possible detriment of your daughters project. Second, it is possible that the dowels were just left in the water too long. The longer they are in the water, the more water they will absorb. If you have a difficulty seeing the marking even though the dowel is soaked, then it may be that more food coloring needs to be added. If you use enough food coloring then the dowel shouldn't have to be in the water for long. Just like dying eggs. The idea is to color the submerged part of the dowel once it is stationary in it's equilibrium position. If you have an egg dying kit it should work even better. I should mention that you should not use red, yellow or orange. It is very difficult to get a good red stain from food coloring. Third, you should check that there are no vibrations. If the bowl is moved or vibrates then the line will be very difficult to see as the dowel will move relative to the water. If you check these and find you are still having the difficulty then "you can also float the cylinders in colored liquid Jello, then allow it to set in the refrigerator. (You may need to occasionally nudge the cylinders away from the edge of the dish.) The food coloring in the Jello will stain the submerged portion of each cylinder."

This might be frustrating trying to get things to work but a large part of science is figuring out how to do an experiment to prove or disprove a theory. There are always differences in the way people do things. For example, you and I can both make cookies from the same recipe but your cookies are fluffy and mine are hard. It turns out that I packed my flour and you sifted yours. It is a slight difference but it can make a difference. This is part of science and the troubleshooting procedure should be documented for the report. Although the experiment is a recipe your daughter will have to make it her own in the end.

On the final question: I would really not recommend turning this in as a "no results" experiment. This experiment is definitely do able and is documented. It is a matter of figuring out what is not working correctly and finding a way to make things work. There are very limited circumstances in which a no results experiment is acceptable. Generally the experiment would be of the students own creation and a significant amount of time, energy and resources would be put into the experiment without success. The work, as always, would have to be documented showing the effort, the students initiative and troubleshooting skills. The effort and creativity are two of the important aspects that judges look for at science fairs.

I hope this helps and good luck! We are here if you need more help.
Heidi

The projects

[rmarz]

Cheri - Your post suggested that the experiment was concluded and is now in the analysis phase. If it cannot be re-run considering some of the points other experts have made (material too porous, too long in the dye solution) your best bet might be to analyze why the experiment produced marginal results and publish that as your submission. It sounds like your daughter was following a description for this experiment obtained from another source as opposed to creating her own hypothesis. Were specific materials specified such as a birch dowel as opposed to an oak dowel? Was the preparation of the dye material described and followed. The time in the dye (several hours) seems too long, allowing for a lot of absorption and capillary activity in the wood cells. Were dowel sizes suggested for the experiment? Is it possible that the dowels rotated over time in the solution or multiple dowels actually disturbed each other while in solution? Perhaps some of the instructions weren't properly followed.

There may be many perspectives that might suggest that the experiment was poorly constructed if you followed their suggestions precisely and obtained poor or un-measurable results. That may be a reasonable path to explore if there is no time to try another experiment. Good luck, often more is learned from an experiment that didn't yield expected results as long as a different understanding is achieved from the effort.

Rick

[cwaring]

Thank you to all. Going to try again with different material. The dowels we used were pine which absorb alot and quickly. Hopefully if she uses stronger dye and shorter period with differet wood we can produce results in a short period of time.

Thanks again

Cheri & Kacy-Anne

[deleted-71588]

One other thing you might try if you continue to have difficulties is to imerse the dowels in water without any dye, let them float and settle, then add a thin layer of a thick oil based dye/stain that will float on the surface, and then quickly remove them carefully using tongs or something similar that will preserve the orientation of the dowels as they are lifted out.

[cwaring]

Well, we had to turn in the project this morning. With the alternate dye and oak dowels in place of pine it turned out worse than the original experiment. the procedure called for regular food coloring. I was unable to find easter egg dye but I did use a higher quality gel / paste dye used by chefs. Still did not work, in fact the oak was very resistant to any markings, less time more time or any time.

We used the dowels from original try, two of them had a slight line that we could figure the tilt angle on but the rest are just a straight line across which results in a 0 degree angle. She tryed and that is what counts. We may try the experiment again on our own when we can get our hands on some egg dye! It was kind of frustrating for her since her project last year did not have huge results either.

There is always another project so wish her luck with her grade!

Thanks again to all for all the help and suggestions.

cheri

[deleted-71447]

Cheri,
Just for future reference, was this the experiment you were attempting?
http://www.sciencebuddies.com/science-f ... ?from=Home
Were the two dowels with a measurable angle the shortest ones of the bunch? That would be the typical expected result.
It sounds like you and your daughter put in a great effort. Congrats on that.
I hope you will check back with us again on the next project.
Chris

[cwaring]

Chris G-
FYI - It was the shorter of the dowels but with the largest diameter. We used 5 different diameters and 3 different lengths.

I will use you guys again, did not know help was out there!

Have great day to all! Now I have to go back to my real job as an accountant!

[deleted-42343]

bobby15 asked this question:

"I just started with the Buoyancy of Floating Cylinders Project and I am running into the same difficulties as posted previously. The food coloring is seeping throughout all the wooden cylinders and the jello did not make any useable line. I will try egg coloring as it is readily available now, but does anyone have any further ideas on how to make this experiment work properly. Appreciate the help"

I split bobby15's post into a new topic, which you can find here: https://www.sciencebuddies.org/science- ... 550#p25190