Rock Density

Let's take a look!

What type of experiment is this?

Experimental procedure and explanation:

• Measure the density of various rocks. Measure it in the same way as described in “Which is Heavier, Water or Stone?”
• Place a container filled with water on the scale and reset the display to zero (0 g).
• Submerge the rock halfway to determine its volume, then fully submerge it to measure its weight (mass).
• The volume of the granite, including 3.7 cm³ from the tongs, is 74.7 cm³, and its weight (mass) is 184.4 g.
  The density is calculated as
  (Density) = (mass) ÷ (volume) = 184.4 (g) ÷ (74.7 − 3.7) (cm³) = approximately 2.6 (g/cm³).
• The volume of the basalt is 59.5 cm³ (including 3.7 cm³ from the tongs), and its weight (mass) is 150.0 g.
  The density is calculated as
  (Density) = (mass) ÷ (volume) = 150.0 (g) ÷ (59.5 − 3.7) (cm³) = approximately 2.7 (g/cm³).
• The volume of the crystal is 15.3 cm³ (including 3.7 cm³ from the tongs), and its weight (mass) is 30.8 g.
  The density is calculated as
  (Density) = (mass) ÷ (volume) = 30.8 (g) ÷ (15.3 − 3.7) (cm³) = approximately 2.7 (g/cm³).
• The crystal used here is quartz.
• Try measuring the density of various materials—not just rocks.
• This video was produced with the support of the JSPS Grant-in-Aid for Scientific Research (18K03956).

[Keywords]	Buoyancy
[Related items]	Which is Heavier, Water or Stone?
[References]	Ryozo Ishiwata and Mitsumasa Nemoto, “The Wonder of Flow,” Kodansha Bluebacks, pp. 48–51. Ryozo Ishiwata, “Illustrated Fluid Dynamics Trivia,” Natsume Publishing, pp. 188–189.

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