|
|
There are more nerve cells in one human brain than there are stars in the Milky Way.
The ratio of hydrogen atoms to oxygen in water (H2O) is 2:1.
Intradermal injections are somewhat difficult to correctly administer because the skin layers are so thin that it is easy to accidentally punch through to the deeper subcutaneous layer.
There used to be a metric calendar, as well as metric clocks. The metric calendar, or "French Republican Calendar" divided the year into 12 months, but each month was divided into three 10-day weeks. Each day had 10 decimal hours. Each hour had 100 decimal minutes. Due to lack of popularity, the metric clocks and calendars were ended in 1795, three years after they had been first marketed.
Vaccines cause herd immunity. If the majority of people in a community have been vaccinated against a disease, an unvaccinated person is less likely to get the disease since others are less likely to become sick from it and spread the disease.