Mineral Lab

Hello there, ever thought about minerals? And what affects their density?? In my class, 6b, we had a lab just to find out about what affects the density of a mineral. We were mostly concentrating on this basic question: does the size and structure of a mineral affect its density? Before we started this lab, my hypothesis was that of course the size is going to affect the density because that is how tight the particles are pressed together and how much pressure is added on them. Essentially, the volume of a mineral is also going to change because the volume is how much of the particles fit into the mineral, and that all is based on its shape and size. Something we talked about in class was also the controlled variable, the manipulated variable and the responding variable. The controlled variable is something you can control how much you have of, and in this case it will be the water in the graduated cylinder. The manipulated variable is the variable that changes, and in this case it would be the minerals. Lastly, the responding variable was going to be the density which was going to give us the answer to everything.

Materials:

In this lab we used a scale, a graduated cylinder, water, and 2 different types of minerals from which we used 3 from: Olivine and Sphalserite.

Procedure:

1)Get all my minerals ready and fill in the graduated cylinder to about 100ml

2) Weigh the first mineral on the scale, and then do the same to the others (record this data in your table)

3) Place the first mineral into the water and record down by how much the water rose.

4)Go re-fill the graduated cylinder so the water is at 100ml and do the same with the other minerals

5) As you have recorded all your information, divide the mass by the volume and get your density

6) Observe your results and build a conclusion.

Once we  finished going through our procedure, and we were up to step 6, we made our graph on excel and made a data table.

Data Table:

	Mass-grams	Volume-ml	Density-grams over ml
Olivine 1	40,3	17	2,37
Olivine 2	39,9	15	2,66
Olivine 3	37,5	14	2,67
Sphalserite 1	53,7	15	3,58
Sphalserite 2	15,4	5	3,08
Sphaserite 3	40,75	10	4,075

From this data table, we were able to make a graph which made our data more clear. One graph for the olivine minerals and the other graph for Sphalserite. The x axis, which is the latitude, shows what we were measuring, either mass,volume or density. The y-axis, longitude one, shows the number of____(for example 40 grams,mass.)

Olivine graph:

 Sphalserite graph:

 












An olivine looks like this: 

For both minerals, we tried to go from biggest to smallest, but either ways, it didn't really make any difference because the graph helped us the most. 

Data Analysis:

If I observe the graph,and think about the lab, I observed that the water would always change due to the minerals weight and volume. Of course while weighting the minerals, the scale weight changed, but something we had to be very careful with while weighting the minerals, was that every time we would weight an other mineral, we would have to make sure that we started at 0. Our data was a big part of this lab because if we did anything wrong while writing down the mass and volume, our density would have come out wrongly. 

Conclusion:

After finishing the whole lab, my final answer is that the size and the structure of the mineral could affect the volume, but the density usually stays the same in one rock. If you look at the graph, you can see that by the Olivine, the density is pretty much in the same category even though the volume and mass are different. I think its like this because it doesn't matter how many particles are inside of the mineral, but how much they are pressed together, and each mineral is different, but if they are out of one section, they will have some sort of same characteristic: density. The shape can mostly affect the volume, but the density not always. From what I have researched, and listened to from class, no matter how big or small a mineral is, it should always be in the same density group.One reason may be that they are made of the same material.Lastly, I learned that volume,mass and density have something in common and without one of them, you could not get the other one, simply like a little scientific family.So after all, my hypothesis wasn't really correct for the guiding question because I stated that the density is affected but I think I meant the volume.

Further Inquiry: 

 During the experiment, I think my partner and I might have done some mistakes, because first of all, while we were placing the minerals into the water, our first trials water got a bit out, so we weren't sure by how much the water rose. To be sure that we got the right answers for density,I checked on a few sites, and it said that the density of Olivine should be from 3.27-3.37
( http://www.ehow.com/facts_6934653_density-olivine.html )
...we didn't have that...The closest density to that number, was the one from the smallest sized olivine mineral. The Sphalserite density should have been between 4-4.1
http://nevada-outback-gems.com/mineral_information/sphalerite_mineral_info.htm
. My answers were pretty much about that number, maybe a bit less but only a few numbers off.I think I did better measuring the density,volume and mass of the Sphalserite because the numbers and answers matched more to the true facts from the internet.  Next time we have an experiment like this, I think I should try to do more trials with one mineral and compare them with the others as well because I just concentrated on getting the answer and not really on the lab. But except for that, I think the lab went very well and we finished in time.