In the early 20th century, tanned skin was associated with good health. However, people began to protect themselves against potential overexposure to avoid sunb

In the early 20th century, tanned skin was associated with good health. However, people began to protect themselves against potential overexposure to avoid sunb

The concept of expressing acidity as the negative logarithm of the hydrogen ion concentration was defined and termed pH in the beginning of the 20th century. Th

The third edition is a comprehensive and updated overview of positive and negative effects of UV-exposure, with a focus on Vitamin D and skin cancer. Researcher

A unique collection of thirty experiments ranging from ancient astronomy to cosmology, each containing one or more challenges for the reader. The progression he