candle carousel

[runnergirl109]

Hi! One of my students is doing her project on the candle carousel that she found here on science buddies. She has made the carousel and followed all the instructions, but can't get it to work. I saw there were some troubleshooting ideas we can use, but thought I would post here to get any help we can. Any helpful hints on getting this project to work correctly?
THanks - Sara Stewart


[Administrator note: Project url: https://www.sciencebuddies.org/science- ... e-carousel ]

[amyCC]

Hi Sara - I'm sorry to hear your student's carousel isn't working. By that, I am guessing it isn't spinning at all? All four candles are lit? How tall is the skewer? How tall are the candles?

As you mention, there are troubleshooting tips in the project, a number of them actually.

If the blades do not spin after waiting for 2–3 minutes (min), try to troubleshoot by checking the following:

• Make sure the candle flames are completely upright and are not flickering or moving sideways. If they are flickering or moving sideways, there may be air movement that is disrupting them. The flames need to be completely upright for the candle carousel to work well; if the flames are not upright, the hot air will not be moving directly upward to the blades.
• Make sure the windmill part is sitting horizontally on the skewer (and parallel to the carousel's stand). If the windmill is tilted on the skewer, the straw may be rubbing the skewer (creating friction) and preventing the blades from spinning.
• See if there are any other possible sources of friction that could be slowing down the blades' spinning. To do this, look at where the skewer and straw meet. The skewer should ideally only touch the aluminum on the windmill where you drew the dot (within the nut). It should not touch any double-sided tape that you used to attach the hex nut to the pie pan.
• Make sure the blades are all at a 30° angle, and that the straight strips on the windmill are still straight and horizontal (and parallel to the carousel's stand).
• The aluminum strip should be too light to affect the balance of the candle carousel. However, if you feel that it poses a problem, try to make it shorter or narrower to minimize its effect on the spinning behavior.
• You could try making the skewer shorter, as this will decrease the distance that the hot air has to travel from the flames. If you do this, blow out the candles, remove the windmill part from the skewer, and try to carefully pull the skewer straight out of the Play-Doh. When you make the skewer shorter, make sure the windmill's blades will still be at least about 5 cm above the flames of the lit candles. Stick the shortened skewer straight back into the Play-Doh hole and try the candle carousel again.

This really is the best place to start. Without seeing what is happening with her specific carousel, it is hard to suggest something else -- because these steps need to be gone through first to try and troubleshoot.

Seeing photos of the carousel might reveal something that could be going on.

Do the blades spin freely when you just spin them by hand? Just making sure that they do have the ability to spin.

Let us know more about the setup and what is happening.

Amy
Science Buddies

[runnergirl109]

the biggest issue we are having now is getting the hex nut to stay in place. we can't find anything strong enough to hold it there so it falls before it can really get going. any thoughts on this?

[amyCC]

In the video, tape is shown wrapped around the straw to make the fit tighter. Watch this part again and see if that helps:

https://youtu.be/hX9GVMyA6Us?si=4e7VQuBpLt1N3XaO&t=123

Amy
Science Buddies

[runnergirl109]

the straw fits fine in the hex nut but the double sided tape we are using to hold the hex nut to the blade contraption will not hold it up. the hex nut with the straw in it keeps falling down to the plate.

[amyCC]

I see. The blade portion should be fairly light. You cleared out any tape from the very center of the hex nut, right? You've tried maybe doubling up the tape to create a better hold?

When you assemble that portion and stick it to the blades, you have something like this:

hexnutcarousel.png (445.2 KiB) Viewed 6127 times

You are pressing firmly there, using the surface to press down and try and increase the hold of the tape?

If I understand your problem, correctly, when you then turn that unit over and carefully put it on top of the skewer, the blades are just falling off?

The project calls for heavy duty mounting tape, double-sided. Is that what you are using? Are you able to try another tape?

Amy