题目

Smooth balls of ice rolled ashore on a beach in Finland and piled up like a huge bunch of turtles' eggs. But where did these “ice eggs” come from?Amateur photographer Risto Mattila stumbled upon the strange sight while walking with his wife on Hailuoto Island. The temperature remained around minus 1degree Celsius that day, he said, and the wind blew quickly across the beach. “There we found this amazing phenomenon. There was snow and ice eggs along the beach near the water line”.The “ice eggs” littered an area the length of about one-quarter of a football field and ranged in size f小明在溪边捡到一个形状不规则的漂亮小石块，拿在手里沉甸甸的，他想测出小石块的密度，但手边只有弹簧秤，于是他找来一根细线和一个盛有水的烧杯，进行了如下实验（g取10N/kg）：（1）将小石块悬挂在弹簧秤下，示数如左图所示，则小石块的重量为________N；（2）将小石块慢慢浸入水中，弹簧秤示数将逐渐________（选填“变大”、“变小”或“不变”）；小石块浸没到水中后，弹簧秤的示数如图所示，此时小石块在水中所受的浮力为________N；小石块的体积为________m3；（3）由此可计算出小石块的密度为________kg/m3；（4）若将右图烧杯中的清水换成盐水，弹簧秤的示数将________（选填“变大”、“变小”或“不变”）．