The size of atoms
IN LAB, we've been using some material from "Explorations in Physics" by David Jackson, Priscilla Laws and Scott Franklin. specifically, from their Unit C on Heat, Temperature, and Cloud Formation
The size of atoms
In this activity, we'll estimate the size of atoms (using pepper and soap, Section 2.1.1).
- We measured across the region cleared of pepper to be approximately 13 cm. Take this as roughly the *diameter* of a circle. Use this, and the diameter of the starting "drop" according to the lab photograph to estimate the length, $h$, of a soap molecule.
Report your results in both millimeters and meters.
[Here's a video of the demonstration (and calculation result) from a covid year]:
We're going to estimate the original size of the drop according to figure 2.6. $r_\text{sphere}\approx 0.15mm$. (If you used a slightly different number, that's OK.)
I estimated the pepper-free region as a circle, with its diameter extending on the ruler from 14 to 10.5cm, that is $14.0-10.5=3.5$ cm$=35$ mm
I found a thickness of 0.00001... mm = $1\times 10^{-5}$ mm..