working siphon?

[biorandom]

How could I somehow get syrup to travel up and down a tube via passive transport? It's for a school project. I can't help the project. I might be able to get away with starting the siphon, then letting it do whatever, though. I just don't know how I'd get the syrup to travel back up? unless someone has other ideas? thanks.

 

Btw, it's supposed to replicate phloem.

Edited October 15, 2010 by biorandom

[Mr Skeptic]

OK, your siphon has to be such that the bottom end is below the water level. To get it to function, you need it to be full of liquid to below the level of your pool of liquid. That way the weight of the liquid on that side is greater than on the other side, and it pulls it up and in. If there are bubbles, you'll need it to be a little extra below, since the bubbles are light and stretchy.

 

The two ways I know of to get a siphon going are to suck on the bottom end like a straw, or to dunk the whole thing in liquid and hold your thumbs over the ends. Note that if you dunk it in water (because the syrup is sticky) you'll need it to be a little extra below the syrup because the syrup is probably more dense. Basically, what I'm saying is have a lot of extra room below your pool of syrup, in case you need it. This will also make the siphon drain more quickly, though that might not be what you want for the demonstration.

[biorandom]

Thanks for the reply. the issue I'm having is how would I have it go down, then back up, or vice versa? I know how to get the siphon to go upward. Another suggestion my father gave me was possibly try a chemical reaction such as baking soda and vinegar or take a 2 liter of pop, have it be opened, HOPEFULLY push the syrup up, then let gravity pull it back down. Any of these seem reasonable?

[Mr Skeptic]

If you want to reverse the siphon, you need to lift the other end so it is higher than the first.

 

Thanks for the reply. the issue I'm having is how would I have it go down, then back up, or vice versa? I know how to get the siphon to go upward.

 

I'm not sure what you're talking about here. Are you talking about capillary action, or a siphon? Could you explain it better?

[biorandom]

If you want to reverse the siphon, you need to lift the other end so it is higher than the first.

 

 

 

I'm not sure what you're talking about here. Are you talking about capillary action, or a siphon? Could you explain it better?

 

Basically I don't care how I get it done; I just need to get syrup to travel up and down "passively.". I just thought of using a siphon somehow or a chemical reaction to push it up then once reaction is over to let gravity pull it back down. I'm just wondering whether or not these could be plausible ways to get it without myself manually moving things throughout the processes.

[Mr Skeptic]

To do the siphon passively, you'd have to do it by filling the tube with water and holding the ends shut until it is in position. Otherwise you have to suck or push the fluid up it.

 

However, if you use capillary action, the water will go upwards due to surface tension, for a limited distance. I suggest using water (maybe with food coloring) rather than syrup, since it would be closer to what goes on in the tree. Syrup would be much too thick.

 

So here's what I suggest: get a glass very full of water. Get a piece of paper towel, and fold or roll it into a thin long strip. Then place one end into the water, and the other end hanging over the edge of the glass. Do this at home to see what it does.

 

Note that capillary action is one of the aspects of how trees work, so I would think this would be even better than a siphon.

[biorandom]

To do the siphon passively, you'd have to do it by filling the tube with water and holding the ends shut until it is in position. Otherwise you have to suck or push the fluid up it.

 

However, if you use capillary action, the water will go upwards due to surface tension, for a limited distance. I suggest using water (maybe with food coloring) rather than syrup, since it would be closer to what goes on in the tree. Syrup would be much too thick.

 

So here's what I suggest: get a glass very full of water. Get a piece of paper towel, and fold or roll it into a thin long strip. Then place one end into the water, and the other end hanging over the edge of the glass. Do this at home to see what it does.

 

Note that capillary action is one of the aspects of how trees work, so I would think this would be even better than a siphon.

 

Teacher is forcing us to use syrup for a grade . if i had capillary tubes, would baking soda/vinegar push it up then once it's done reacting let gravity pull it down? or you think syrup is too thick?

[Mr Skeptic]

Did you even bother to do the experiment I suggested?

 

For better grades, I think you should use a more accurate sap imitation. According to this, sap is about 2% sugar, and that's for sugar maples. It's a different story if you're talking about pines, but those are resins and not syrup.

 

http://www.mi-maples...es_homemade.htm

[biorandom]

Did you even bother to do the experiment I suggested?

 

For better grades, I think you should use a more accurate sap imitation. According to this, sap is about 2% sugar, and that's for sugar maples. It's a different story if you're talking about pines, but those are resins and not syrup.

 

http://www.mi-maples...es_homemade.htm

 

I honestly haven't tried it. I'm waiting until the school week starts and before I even think about purchasing supplies (where would I find capillary tubes?)

[Mr Skeptic]

I said a piece of paper towel, rolled or folded into a thin strip.

[biorandom]

Sorry for the delayed response. I conducted that little experiment. I do notice how the water continues to travel. I tried it with syrup, I didn't see any effect, unless it was simply very minimal. That being said, if I were to get this to work, how would I let it go back down?

[Mr Skeptic]

If your glass is full enough, then the water will travel far enough along the paper to act as a siphon, I think. For that you'd need to hang the paper over the edge of the glass and the water needs to reach all the way up over the edge and back down to water level on the other side. If it does, it should act as a siphon, but rather than suction due to the tubes it will be like pulling due to the water's surface tension. It'll be slower than a siphon though.

[biorandom]

If your glass is full enough, then the water will travel far enough along the paper to act as a siphon, I think. For that you'd need to hang the paper over the edge of the glass and the water needs to reach all the way up over the edge and back down to water level on the other side. If it does, it should act as a siphon, but rather than suction due to the tubes it will be like pulling due to the water's surface tension. It'll be slower than a siphon though.

 

I see... I still do have the syrup and the paper towel going, however, I don't have much syrup in the cup, which may be a reason. despite that, i do see progress, but again, very slow.

 

http://img176.imageshack.us/img176/8167/stem.jpg

 

What are your thoughts of that?

 

This is more of what I actually have tested so far: http://img534.imageshack.us/img534/8239/stem2.jpg

 

I'm still a little confused EXACTLY what shape you want this to take. Thanks.

[Mr Skeptic]

The second one. The first one would be a perpetual motion machine, which never work.

[biorandom]

Hmm.. alright. Any way you think to move it a little faster?

[Mr Skeptic]

Not really. Then again, it's not all that fast in trees either.