厦imddm Ha=24 r/H=0.50 theta<10 deg FIG.8: The first toy model made with wooden blocks. The structure appears to break at f=0.5, and at a small angle 0 100, which can be estimated by measuring the angle formed by the upper part of the tower with the vertical. Bundy noted in his work20 that the use of a model to test a real chimney would be useless due to a"scale effect. The stresses inside the chimney depend roughly on the scale of the object, so that real chimneys would develop bigger stresses than equivalent small scale models. therefore breaking earlier in their fall. Nevertheless we found it interesting to 6 and 7. It was also supposed to be difficult20 to show these effects with toy models a figs reproduce these effects in small scale models to test especially the discussion based on Fig 8 is the first example of one of our toy models. We made a tower by simply stacking 24 wooden toy blocks of cubic shape, for a total height H=0.76 m, mass m =0.32 kg and a ratio H= 24. the value used in Fig. 6. The tower was set into the falling motion by removing a support at the bottom, inducing a rotation without slipping at the bottom point. The picture clearly shows the rupture"due to bending of the structure at exactly half the height,H=0.50, and for a small angle 8 10, which again can be estimated by 15FIG. 8: The first toy model made with wooden blocks. The structure appears to break at r H = 0.5, and at a small angle θ . 10◦ , which can be estimated by measuring the angle formed by the upper part of the tower with the vertical. Bundy noted in his work20 that the use of a model to test a real chimney would be useless due to a “scale effect.” The stresses inside the chimney depend roughly on the scale of the object, so that real chimneys would develop bigger stresses than equivalent small￾scale models, therefore breaking earlier in their fall. Nevertheless we found it interesting to reproduce these effects in small scale models to test especially the discussion based on Figs. 6 and 7. It was also supposed to be difficult20 to show these effects with toy models.38 Fig. 8 is the first example of one of our toy models. We made a tower by simply stacking 24 wooden toy blocks of cubic shape, for a total height H = 0.76 m, mass m = 0.32 kg and a ratio H a = 24, the value used in Fig. 6. The tower was set into the falling motion by removing a support at the bottom, inducing a rotation without slipping at the bottom point. The picture clearly shows the “rupture” due to bending of the structure at exactly half the height, r H = 0.50, and for a small angle θ . 10◦ , which again can be estimated by 15