Lab Report: What happens if put bones into vinegar.

My son's lab report for studying human bones and learning how a base will dissolve the calcium in bones.   I needed to assist my son in preparing the bones, but otherwise he did the experiment himself.  He asked me to handle the bones after they sat in the vinegar.  He took the pictures.  :)

Hypothesis: Vinegar would weaken the uncooked bone, and it would not weaken the cooked bone in vinegar.   The bones not in vinegar... The uncooked one would not break and the cooked one would break. 

Procedure: We put one cooked bone and one uncooked into vinegar and let them in there for five days.  After five days we took them out too see what would happen.   We put one uncooked and one cooked bone on a plate and left them to sit for five days.

Observation: 
The bones in vinegar were both bendable.  The uncooked bone was more bendable than the cooked bone.  You could bend the ends of the cooked bone but not the middle.   With the uncooked bone you could bend the entire thing.   The ones in vinegar, the cartilage came off, it was gloppy with the uncooked one... spreadout with long strands, the cooked one stayed together but was mushy.  Both bones not put in vinegar were not bendable. 

Uncooked bones in Vinegar

Cooked Bone in Vinegar

Conclusion: Vinegar weakens bones and cartilage.  Letting bones air dry makes them harder.   Vinegar is a base and bases dissolve things.

Lab Report: Icebergs Melt At Different Rates in Salt and Fresh Water

My son is learning to make a lab report, so I'm transcribing his report for him as I'm proud of the effort he put into this.  This came up as part of studies on Canada.

Hypothesis: Icebergs will melt faster in freshwater than in salt water.

Procedure: Get two bowls.   Make one bowl saltwater like the ocean 3.5% salt needed.   Have the other bowl be fresh water.  Let the bowls sit so they are same temperature.   Freeze two cups of water in two identical cups.   Take them out of the cups when they are completely frozen.  Use cold water to get them out of the cups.   Weigh them.   Put them in their bowls.  Then weigh them 30 minutes later, Then 15 minutes later.

 I noticed at 30 minutes that the fresh water one had melted the most.   At 15 minutes I did it again and noticed the same thing.  

Observations: take the icebergs out of the water and weigh them.  They will be slippery and cold plus you don't want the heat of your hands changing the results so wear gloves.   Put them back in the water as soon as you weigh them.

Conclusion: Because the fresh water one melted the most I proved my idea correct.  Fresh water will melt icebergs faster than the saltwater probably because of the salt in the water.

Other questions raised:


I noticed that both Filli and Killi were left with their heads frozen in the ice and wondered why their heads thawed out last.