Laboratory work 1: Studying the structure and composition of bones
The aim of the laboratory work is to observe the composition and structure of bone. A prepared collection of long bones or a cleaned animal bone (for example, chicken bone) is examined: surface, middle, ends, cavity and traces of marrow. Two experiments identify the substances in bone. In the first, a bone is kept in a mild acid solution (for example, vinegar) for several days: mineral salts dissolve and the bone becomes soft and flexible. In the second, a bone is heated in a flame: organic substances burn away, the bone becomes white and brittle, and crumbles when pressed. Conclusion: bone consists of organic (flexibility) and mineral (hardness) substances. This work is done only by the teacher or adults: students do not handle acid or fire; eye protection and hand washing are required.
Make a results table: experiment – observation – conclusion. Write which experiment showed which substance. Note: the teacher demonstrates; you observe and record.