Miss SC March 12, 2008

Minerals in Bone

A. Purpose:

The purpose of this experiment is to show the effect of minerals in bones. Vinegar will be used to dissolve the minerals of a chicken bone, replacing the minerals with collagen, which will make the bone flexible.

Bones are made of cells that are surrounded by bone matrix. Bone matrix is made up of basically two things: collagen and minerals. Collagen, a flexible and rubbery substance, belongs to a certain class of chemicals called proteins. The minerals however, are rigid, hard chemicals which usually contain calcium. Because of the right amount of collagen and minerals, bones are both strong and flexible. Without collagen, bones would be brittle. For example, if someone did not have any collagen, whenever that person fell, that person's bones would just break instead of bend. But without minerals, bones would be too rubbery. 

One terrible bone disease that is an area of research is called Osteogenesis Imperfecta (or OI). OI is a genetic disorder that causes bones to break easily and sometimes for no particular reason. OI can cause weak muscles, brittle teeth, a curved spine and hearing loss. A person can have as much as several hundred fractures in a lifetime! The cause is a gene defect that affects how collagen is made.

The following experiment hopes to show that by removing minerals from a bone will make a bone flexible and able to bend in time. The minerals will first start dissolving from the ends of the bone.

This topic is of interest to science because of the extraordinary structure of a bone. Scientists to this day are still continuing to hope to conquer the feat of creating a material that is "as strong as steel but as light as aluminum."

B. Equipment:

1. An uncooked chicken bone (preferably a smaller one like a wishbone or a wing)
2. A jar with a lid
3. Vinegar (preferably white)

C. Procedures:

1. Clean the bone of all meat and tendons. Make the bone as bare as possible.
2. Allow the bone to dry overnight
3. The next day, test the bone by trying to gently bend the bone. Do not use so much force that you break the bone! Notice that the bone bends a bit, but the bone is still mostly rigid.
4. Fill the jar with enough vinegar so that the bone will be fully immersed.
5. Drop the bone in the jar and close the lid.
6. Every day, pull the bone out of the vinegar and test the bone as done in step (3).
7. Note the observed difference.
8. Put the bone back into the vinegar and close the jar again.
9. Continue this process for 7 days or more.

D. Observations:

1. All the meat and tendons on the chicken bone were cleaned off.
2. The bone was allowed to dry overnight.                                     
3. The bone was gently bent. The bone bent a little but the bone was still mostly rigid.          
4. The jar was filled with enough vinegar to fully cover the bone.                 
5. The bone was then dropped into a jar and the lid closed.
6. The next day, the chicken bone was taken out of the jar of vinegar. The bone was a little less rigid than before but still pretty hard.                                                                                                      
7. The bone was put back into the jar of vinegar to sit for another day.                                
8. Everyday, the bone was taken out of the jar of vinegar and bent to see how flexible the bone was. Each day, the bone got a little more flexible, starting at the ends of the bone and then came towards the center.                                                   

9. At the end of 7 days, the bone was very rubbery and flexible.

E. Conclusions:
As predicted, the chicken bone that was stripped of meat, dried overnight, and put into a jar of vinegar, did indeed get flexible and rubbery because the minerals dissolved. With the right substance, the substances in a bone (collagen and minerals), can change. As the bone in the experiment sat in the vinegar, the minerals kept on dissolving since vinegar dissolves minerals. So what was left was only the rubbery collagen. And since the flexibility started at the ends of the bone, that must mean that minerals dissolve more readily at the ends of a bone. 

A way to improve this experiment could be to continue testing the bone once a week and see if the bone ever stops getting more rubbery. Since one chicken's bone differs from another, one could try to use the same kind of bone from a lot of other chickens to get more data.   

An idea for further research could be to find a substance that would dissolve collagen instead of minerals and test the bone to see how hard the bone could get. Another idea could be to use a fish bone the same size as the chicken bone used in the experiment. Then see which bone becomes more rubbery in a set period of time.                                                            

F. Bibliography:

Domain: http://www.clevelandclinic.org
Document: /health/health-info/docs/2600/2610.asp?index=9500

Domain: http://www.oif.org
Document: /site/PageServer?pagename=FastFacts

Domain: http://depts.washington.edu
Document: /bonebio/bonStrength/bonStrength.html

Rosenoff. Steve. Class lecture. February 25, 2008.

Wile. Dr. Jay. Exploring Creation with General Science. Apologia Educational Ministries. 2000.