FIRST EXPERIMENT: Chicken or lambs bones and egg/ Mollusk shells.

• Introduction:

Even though bones very light, they are also very strong. However, how strong they depens on how much of the minerals calcium carbonate (CaCO₃) they contain.

During foetal development, strong fibbers of collagen protein form a matrix for bones. The matrix is shaped like bones but is very flexible. The matrix solidifies by a process called calcification. Durins this process, calcium phospate or hydroxyapatite is deposited in the fibbers of collagen and gives the bones strength and rigidity.

• Material:

1.  Dried, cleaned chicken or lamb bones and egg. Some mollcuscs' shells.
2. Distiled water.
3. Vinegar and acetic acid.
4. 250ml Beaker.
5. Clock glass.

• Procedure:

Chicken or lambs bones:

1. Carefully clean and cut ad much of the meat away from the chicken thin bone as possible.
2. Examine tthe flexibility of the bone by trying to bend it with your fingers.
3. take a beaker and make and acid acetic solution or add vinegar.
4. Take the chicken or lamb bones and drop them in the acid acetic and vinegar solution that you have made.
5. Leave it 24-48 hours and see what happens to the bone. put a clock glass at the top of the beaker to protect the solution.
6. Remove the bones from the vinegar with a tong and soak them with water.
7. Write the results in your lab worksheet.

Mollusks shells:

1. Take another beaker and make the same acid acetic solution.
2. Put inside some shells and make note of what is happening.
3. write the observations in your lab worksheet.

• Resolts or Obserbations:

When we put the bones, egg and shells almost immediately we can see some bubbles coming up to the surface. And after several hours we can see how the shell of the egg disappeared and bones are not lost its rigidity.

• Conclutions:

The acetic acid and vinegar are dissolved organic matter and the bubbles that were detached at the beginning of the experiment is carbon dioxide caused by a chemical reaction. Have lost bone collagen and thus its rigidity.

• Questions:

1. Write the reaction that takes place when the acid acetic reacts with the calcium. CH₃COOH + CaCO₃ = CO₂ +Ca(CH₃COO)₂
2. What is happening when the shells are soaking of acetic acid? What are the bubbles that you can see? Drove a bubbles. The bubbles are carbon dioxide.
3. What is happening to the bones after some days of soaking it in acetic acid? Why is the bone flexible now? Lose rigidity. The bone is flexible because it loses calcium carbonate.
4. So, what is the fuctions of the calcium carbonate in the skeletal structures? Rigidity.
5. Increases in carbon dioxide to the atmosphere from the burning fossil fuels and deforestation threaten to change the chemistry of the seas. Evindence suggests that this increase in atmospheric carbon dioxide is lowering the pH of the oceans in a process called ocean acidication. How can acidifaction affects coral reefs? Coral reefs die and disappear.

 

• Photos: