Sinking in a Non Newtonian fluid!

[deleted-189826]

This year for my science project, I will be experimenting with Oobleck. Oobleck consists of cornstarch and water.I will make 3 different oozes with different viscosities. One will have the perfect amount the other will have too much cornstarch and the last one will have too less cornstarch. Then, I will take an object and put in in all three oozes. Next I will time how long it takes for the object to reach the bottom. I will do the same with two of the objects superglued back to back. Then, I will coat them with different substances and try again. What substances should I use? What should I use to put in the Oobleck? What should the purpose be? Is there any other way to improve this science project? Please answer ASAP

[SciB]

Hi Kelsey,

Sorry that none of the experts has attempted to answer your question. Do you still need help? Let us know and I will get back to you right away.

It might be more appropriate to post your questions on the physical sciences forum rather than life sciences because they are more of a chemistry/physics type.

Regards,
Sybee

[Administrator note: this topic has now been cross-posted in Physical Sciences.]

[deleted-189826]

Thank you for your consideration and yes, I do need help with my experiment.ASAP.
This year for my science project, I will be experimenting with Oobleck. Oobleck consists of cornstarch and water.I will make 3 different oozes with different viscosities. One will have the perfect amount the other will have too much cornstarch and the last one will have too less cornstarch. Or should I change this by having the standard Oobleck in all three jars. Then, I will measure the rate of speed an object is sinking. After this, I will take a three inch wooden stick ( rectangular) and put down measurements on them. put in in all three oozes. Next I will time how long it takes for the object to reach the bottom. I will do the same with two of the objects superglued back to back. Then, I will coat them with different substances and try again. What substances should I use? What should I use to put in the Oobleck? What should the purpose be?there any other way to improve this science project? Please answer ASAP. Should i add other variables? Please give me some advice to improve this experiment.

[deleted-2131]

Hi KelseySanders,

Have you checked out the Science Buddies' Project Guide? It has some great information about deciding on and writing up your purpose, question, hypothesis, variables, etc. It's a really awesome resource for helping you with your science project.

https://www.sciencebuddies.org/science- ... ndex.shtml

For your experiment, you will want to have one independent variable and one dependent variable (take a look at the "variables" section under the "constructing a hypothesis" section of the Project Guide). The independent variable is the thing you change. Right now, it sounds like you are planning to change three things, (1) the cornstarch/water ratio, (2) superglued or not superglued, and (3) coated with different substances. I would suggest picking one of these variables and exploring how sinking time responds to changes in that one variable.

Let us know if we can help with anything else!

[SciB]

Hi Kelsey,

I’m having a little trouble coming up with a hypothesis for your project, but I think what you’re getting at is some way to reduce the friction between the stick and the oobleck. As I’m sure you know, oobleck is a weird sort of liquid that becomes hard if you hit it or move your hand through it quickly. I assume you are using it as a model for quicksand, so I wouldn’t make it too thick. Also, as I understand quicksand, it acts the opposite of oobleck. When pressure is applied to quicksand it becomes LESS viscous. That’s why when a person steps on it they start sinking.

Have you done any trial experiments to make sure a 3-inch stick is heavy enough to sink through your oobleck?
I agree with Terik. You should not use so many variables. I would pick one concentration of oobleck and not change it. You can still try doubling the mass of your stick by gluing two together.

The most important variable is the coating that you put on the stick. Raw, unpainted wood should sink fairly slowly because it has quite a lot of friction. Painting the wood is definitely one thing to try and I would use a high-gloss paint like varnish. Sand the wood first if it is not smooth. Make sure the paint is totally dry before doing the experiment.

Oil acts as a lubricant between two solids, but I don’t know if it would do the same between a stick and oobleck. You could try painting the stick with salad oil. Other lubricants that you can buy at a hardware store are graphite and silicone spray. You could try these alone or on the varnished wood.

It’s a really interesting project and I have no idea what will happen which makes it more fun.

Keep posting to let us know how it’s going.

Good luck,

Sybee

[deleted-189826]

Unfortunately, this experiment is not working. When I put the stick in the Oobleck, it tilts to the side and to make it sink fully, I have to put pressure on it. The oil stick is sinking slower but it never makes it ti the bottom. Only when I apply force. I don't know how to measure the force, either. Is there anything I can do? These are the last two days till it's due. Should I change topics? Please help me ASAP

[SciB]

I was afraid that would happen. That's why i asked you if you had done a test first to make sure the stick would sink through the oobleck. Most wood floats, so you probably should have picked an object that was made out of metal to use as your quicksand tester.

You need something heavier and something that has more weight at the bottom so it doesn't fall over. How about attaching a weight to the bottom of your stick? I understand that you planned to measure the sinking by putting a metric scale on the stick so that you could gauge how fast it sank. I don't know what size your stick is so i don't know what to suggest as a weight, but you get the idea. If you have some lead fishing sinkers, they might work well. I just don't know how much weight you need.

Try these suggestions and if you still have trouble, we'll try to help you get this done before the deadline.

Good luck!

Sybee