physics • Ross Churchley

The CRC Handbook of Chemistry and Physics is a 2600-page tome of random facts and figures, from the speed of sound in various media to the chemical composition of the human body.

My sixth-grade teacher’s copy was one of the most fascinating objects of my childhood, and it still makes me giggle with delight.

To give a taste of what the book is like, here’s an abridged version of section 15-39 “Density of various solids”. The idea that someone would need a handy reference for the density of cardboard, sandstone, butter, and thirty-eight different kinds of wood is hilarious — but they must be the most interesting person in the world!

Material	Density
Amber	1.06–1.11
Asbestos	2.0–2.8
Asphalt	1.1–1.5
Beeswax	0.96–0.97
Bone	1.7–2.0
Brick	1.4–2.2
Butter	0.86–0.87
Cardboard	0.69
Chalk	1.9–2.8
Charcoal, oak	0.57
Charcoal, pine	0.28–0.44
Clay	1.8–2.6
Cork	0.22–0.26
Diamond	3.51
Gelatin	1.27
Glass	2.4–2.8
Granite	2.64–2.76
Ice	0.917
Iron, cast	7.0–7.4
Limestone	2.68–2.76
Paper	0.7–1.15
Polyethylene	0.92–0.97
Porcelain	2.3–2.5
Quartz	2.65
Rubber, hard	1.19
Sandstone	2.14–2.36
Sugar	1.59
Wood, balsa	0.11–0.14
Wood, bamboo	0.31–0.40
Wood, cedar	0.49–0.57
Wood, mahogany	0.66–0.85
Wood, oak	0.60–0.90

2023-05-22

The time it takes to properly roast a whole turkey is proportional to its weight to the ⅔ power. My old mathematical modelling textbook specifically recommends 45 minutes per lb^2/3 when cooked at 350℉.

For a spherical turkey of uniform thermal conductivity $\alpha$ and density $\rho$ , a precise formula has been derived:

t = \ln\left(\frac{2(T_h - T_0)}{T_h - T_f}\right) \frac{1}{\pi^2\alpha} \left(\frac{3}{4\pi\rho}\right)^{2/3} m^{2/3}

where the oven is set at $T_h$ and the center of the turkey needs to reach a temperature of $T_f$ from $T_0$ .

The more general ⅔ power law does not depend on unrealistic assumptions about the turkey’s shape or thermodynamic properties; it can be derived from pure dimensional analysis and applied to turkey-shaped meat-based objects by fitting a curve to specific cook times used by chefs.