You can use refraction which is the bending of light through a transparent material. Also the freezing and boiling points of water. One last one is the Cartesian five experiment, this shows the density of water. Hope this helped.
Answer:
Estimates of historical world population
Year 1400 1600
population (in billions) 0.35–0.40 0.50–0.58
growth p.a. >0% 0.15–0.3%
Answer:

Explanation:
The pH scale stands for the power or potential of hydrogen. It measures how acidic or basic a solution based on the concentration of hydrogen ions and a scale from 1 to 14.
This scale is unique because it is logarithmic. So, every time the pH changes by 1 on the scale, the actual concentration of the solution increases or decreases by a tenfold.
So, a solution with a pH of 7 is ten times more acidic than a solution with a pH of 8. This can be translated to:

The black coffee has a pH of 5 and the hand soap has a pH of 10. We want to find how many times more acidic coffee is, so we subtract 5 from 10 and get 5. The difference in pH is 5.

Coffee is <u>10⁵ or 100,000 times more acidic than hand soap.</u>
Like what our backyards look like
if so then my backyard has tons of flowers and a big white shed