Practical 8

What bones are like without calcium salts

In this practical activity, you will find out what happens to bones when the amount of bone salts within them is reduced. This can be brought about by soaking the bone in an acidic substance like vinegar (acetic acid)

Apparatus and materials

• Two clean beakers
• Water
• Vinegar/ acetic acid
• Measuring cylinder
• Two small clean, dry bones of equivalent size (eg. chicken bones)
• Cling-film or equivalent
• Tweezers

Safety

These safety points mainly tell you about hazard. You will need to think about the risk(s) this might pose, and how you can minimize the risk.

• Acetic acid (vinegar) can be an irritant to skin and eyes.

Method

• Set up the two beakers with equal volumes of water in one and acetic acid in the other. Label the beakers.
• Add one bone to each of the beakers.
• After approximately three days, use the tweezers to remove the bone from the beaker with water. Try to bend the bone. What happens?
• Now use the tweezers to remove the bone from the beaker with acetic acid. Try to bend this bone. What happens? How does it feel compared to the first bone?

Discussion

• Why were there different results from the two bones?
• How could a reduction in the amount of bone salts happen inside a living human body?
• What would be the effect of a reduction of bone salts in bones within a living human body?