Bone Decay 9-4 Project 1

Purpose My project will answer what environment and season will/can deteriorate the weight of bones. To do this I will use pig bones because of they’re similarity in chemical composition to a humans, and they will be placed in four different simulated environments as well as simulated summer and winter seasonal temperatures.

Hypothesis The four environments that the bones will be placed in will be fresh water, salt water, soil, and open to the air. My hypothesis is the bone placed in the soil and in the summer season will lose the most weight, and the bone placed in salt water and in the winter season will lose the least amount of weight. I think the soil will deteriorate the most weight because this environment is perfect for decaying bacteria. My reason for why I think the salt water will lose the least weight is because salt is a bacteria killer so the bone will be bacteria free and preserved, and if the water freezes this will cease any bacteria activity.

Materials 1- 8 pig bones 2- 8 separate jars 3- 1 ½ cups of fresh water (de- chlorinated) for each of 2 containers 4- 1 ½ cups of salt water ( 3tbsps salt) for each of 2 containers 5-1 ½ cups of regular lawn soil for each of two containers

Method 1. Weigh and record the original weight of each bone; 2. lay out and number four jars 1-8; 3. place one bone in each jar; 4. in one jar put1 ½ of soil; 5. in the second jar place 1 ½ cups of de-chlorinated fresh water; 6. in the third jar place 1 ½ cups of salt water (3tbsps of salt); 7. and in the fourth and final jar there shall be a bone with nothing in along with it; 8. do the same for four more bones but place outdoors (during winter months) in a high wind cover area; 9. for three weeks let the bones lay in their substances, and at the third week mark weight once more and average the weight lose for three weeks. ****Note**** After three weeks the bones have been exposed to germs, fungus, bacteria, and viruses, THEY ARE NOW A BIO-HAZARD! The bones must be immediately incinerated after the experiment has been completed.

Variables Controlled Variables: amount of sunlight, same pig the bones were taken from, and amount of time each bone has rotted. Manipulated Variables: contained substance of each jar, and simulated season. Responding Variables: loss of weight for each bone in each substance.

Conclusion My conclusion is that my hypothesis was half correct. The bone in soil put in summer conditions lost the most losing 8g. But the bone that lost the least was the fresh water, not the salt water, but still in the winter conditions, actually becoming saturated with the water gaining 7.2g.

Results Bone # (and substance)Original WeightWeight After 3 Weeks Bone # 1 (soil) 26g 18g Bone # 2 (fresh water) 25.9g 27.9g Bone # 3 (salt water) 27g 31g Bone # 4 (control) 21.8g 21.4g Bone # 5 (soil/W) 22.7g 18.8g Bone # 6 (fresh water/W) 24.4g 31.6g Bone # 7 (salt water/W) 29.1g 31g Bone # 8 (control/W) 14.6g

Analysis

Ways to Improve 1. One way to improve would be to have more bones in the same area with each other to see the effect of extra masses in the surrounding area would increase or disperse bacteria activity. 2. A second way to improve would be to expose the bones to decomposers such as earth worms or blowfly larvae.

Sources of Error 1. One way my project my have had a mistake was when I received the bones I did not know if they had been treated with chemical which may had preserved them. 2. Another source of error could have been the cleaner I used to clean out the jars with could have been a corrosive and helped deteriorate the bones. 3. As well as the different amounts of meat which remained could have been part of the final weight.