Inspire Science: Integrated G7 Write-In Student Edition Unit 1 (INTEGRATED SCIENCE)

This book is useless without access to all the companion videos which are extremely pricey. Absolute waste of money.

Producto igual a la descripción y a muy buen precio.

Page 47 discusses phase change as a solid melts to liquid. The only material identified by name is ice/water. The solid's particles are presented on the left with purple spheres stacked 4 layers high on a 4X4 base. Most of the spheres on the visible edges of the cube have a "motion line" drawn outside on the background. Two of them, (one on each left-most corner) and two more of them, (one on each right-most corner) have 2 motion lines with no explanation. The "motion lines" represent kinetic energy... and are drawn as short arcs concentric with the purple balls.The next illustration shows some of the purple balls with doubled "motion lines" concentric with the purple balls and concentric with each other. It shows the balls in a random distribution and moving farther apart as the solid becomes a liquid at the melting point.The third illustration shows all the particles in the liquid state. The balls are farther apart yet. Some of the balls have single "motion lines", and some of the balls have doubled "motion lines" ... and there is no explanation for the difference. Presumably another illustration for the gaseous state would have more space yet between the purple balls, and the "motion lines" might be tripled.The page says the particles move farther apart as the solid changes to the liquid phase. That would mean that a given space or volume would hold fewer particles in the liquid phase than in the solid phase. That in turn means that a solid of a certain mass could not displace all of the same mass of the liquid...The solid would sink to the bottom. Most students have seen ice cubes floating at the top of a glass of water. Most probably the seven Program Authors have seen the same phenomena. Have they seen this page?At the bottom of the page on the left is a beaker of ice cubes, and the red circle contains hexagonal patterns of H2O molecules as a solid. In circle on the right there are more H2O molecules apparently, less organized as a liquid.Perhaps a Physics teacher or professor should be among the Program Authors.