Mrs. Berger's Chemistry and Physics Blog

Of Mice and Men… or Moles and Einstein

Density Bottle Project September 4, 2007

Filed under: Chemistry,Chemistry I — Mrs. Berger @ 11:13 am

A few students have asked, “What do you mean by the term liquid?”  The Chemistry I Density Bottle Project requires at least four different liquid layers.  I think this leads us to exploring the definition and discussing the properties of this state of matter.

According to and the American Hertiage Dictonary, a liquid is the state of matter in which a substance exhibits a characteristic readiness to flow, little or no tendency to disperse, and relatively high incompressibility.  Therefore, in order to qualify as a liquid for this project, the substance must flow, not evaporate into vapor readily and be incompressible.  (this means you can’t smoosh it into a smaller space) 

 Some have asked, “Can I use water with things mixed in to change the density?”  You can try this yourself, but think this out.  If you mix salt with water and if you mix sugar with water, when you pour this into the same bottle, since they are both water, won’ they mix?  Think about substances that don’t mix with water.  Maybe you want to try these.  Maybe you want to check out some properties of water according to the US Geological Survey’s site on water.  This  might help you decide whether or not to even use water.


9 Responses to “Density Bottle Project”

  1. sally pryor Says:

    My 7th grade daughter has this project due on 10/12. We had a min. of 5 liquids all others were extra credit. We are needing some help. We cleaned out our pantry. we have colored water, dish liquid, karo suryp, olive oil, and veggie oil. We added suryp, but it mixed with the karo and honey, did the same. vinager mixed with the water, and milk was not to be used. any other ideals of where to look? some direction would be nice. please help.

  2. Mrs. Berger Says:


    I don’t want to tell you exactly what to do, because I am assuming your daughter’s teacher has one of the same goals in mind that I do when I assign this project – learning. Part of learning is failing, because this is actually just finding one way that doesn’t work. I think Thomas Edison said something to that effect.

    I will however offer you some clues. I don’t know if I like the soap idea in your bottle, because soap’s main goal is to get the water from your faucet to mix with the grease on your dishes so that it will rinse away. You may be having problems because you are using water, a universal solvent (dissolves lots of stuff), and soap, which is made to make water mix with things it doesn’t normally mix with.

    There are two factors at play here in the density bottle – the density of the liquids, which is why it is called the “density bottle project”, and the POLARITY of the substances you are using. This fact is probably way over your seventh grader’s head, but that doesn’t mean she can’t learn a little something from it. It may help you when guiding her, however.

    Oils and fats tend to be nonpolar substances. Water and other water-based substances (like vinegar) tend to be polar. Chemists have a saying that “like dissolves like” so that polar stuff dissolves polar and nonpolar dissolves nonpolar.

    My suggestion to you is to “stick” with the sticky stuff, like syrup, oils, etc, because nonpolar things are less likely to mix if their densities are greatly different. For example, vegetable oil and olive oil, I think, have similar densities, so they don’t tend to stay separated.

    I hope this has been helpful without giving you any “answers.” I think the important thing to remember is that even if your seventh grader gets four layers and has learned something new, the project has been a success.

  3. Mrs. Berger Says:


    Don’t be afraid to venture outside of your kitchen cabinet!

  4. Julia Says:

    We must also make one and I find you advice very helpful. Thank you!

  5. Jocelyn Says:

    Hello I’m in the eighth grade.And I have a density bottle project due this Monday!!And I don’t know understand how to find the density of things.Can you please tell me how to find the density of a liquid?I’m not asking how to do the bottle thing but how do you find densities?

  6. Mrs. Berger Says:

    Jocelyn – I am sorry I did not get back to you sooner. I was on vacation! I hope you figured out your project. To make a bottle, you actually don’t need to know the densities of the substances themselves. You basically just need to guess and test different substances that will not mix with each other to see which ones float and which ones sink. The layer at the top is the least dense and the bottom is the most dense. If you wanted to find a density, though, you would need to measure a certain amount of that liquid and find its mass and volume. Then, divide the mass by the volume, or g/mL.

  7. Chantal Says:

    Hello, I’m in 11th grade and our teacher assigned a prodject due right before christmas break. we have to make an ortament having to do with chemistry to put on our class “chemist tree” however im trying to find the chemical formula for oil to show the teacher i understand and can connect the prodject with polarity 🙂

  8. Aaron Says:

    Hi, I am in eighth grade and I have a density bottle project due this coming Friday. I have some ideas, but wanted to try to look at some info on the web. I’ve been thinking that I can use oil, water, and syrup for the liquids. But I also have to have three solids that float, float in the middle, and sink. For those I was thinking cork (float), a half/quarter filled capsule (float middle), and a marble (sink). Please tell me what you think, any advice would be appreciated, thanks!

  9. Mrs. Berger Says:

    Chantal and Aaron,
    I apologize for not getting back to you in a timely manner. I am positive your projects are long past due. I haven’t been doing a very good job keeping up with my site lately, but still wanted to answer a few of your questions in case anyone asked.

    Chantal – there is not, as far as I know, a chemical equation for “oil”. First of all, there are many types of oil – that used in automobiles, mineral oil, vegetable, peanut, canola, etc. According to Wikipedia – “Chemically, both fats and oils are composed of triglycerides, as contrasted with waxes which lack glycerin in their structure… Although thought of as esters of glycerin and a varying blend of fatty acids, fats and oils also typically contain free fatty acids, monoglycerides, and diglycerides.” ( So as you can see, oils are mixtures of different compounds. Therefore a chemical formula cannot specifically be written for “oil” but you could say they are long hydrocarbon chains with a functional group, such as a carboxylic acid, on the end. Because of these long hydrocarbon chains, oils tend to be very nonpolar – hence they don’t mix well with polar substances such as water.

    That takes us to Aaron’s problem. I do not think it would be wise or prudent of me to tell you what to put in your bottle. I will say you are on track. I usually recommend leaving out water because it is known as the “universal solvent” – in other words, it dissolves A LOT OF STUFF. Try to think of other liquids you may have lying around the house and be wary of those things with a lot of water in them. I constantly have kids trying to say that vinegar and water are different and they find their densities are different, but then they mix. HOwever, for most vinegars purchased at the grocery store, they are around 95% water – they then mix well with water. You can try lots of things for between layers – craft beads, legos, aluminum foil, etc. Just be sure, if you do this again or someone else is reading this that is getting ready to do it, to do it WELL AHEAD OF TIME because substances are absorbed by your floating items and then those items, now being more dense, sink.

    I hope you both did well on your projects and that you don’t give up on me as a source for help. Thanks for checking in – I wish my students would use my site like you two.

    Happy Chemistry!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s