What is proof that the earths magnetic field has changed direction over the centuries

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.

Juju.01) 5 geologic events a group of students designed an experiment in an ice rink to represent the solar system. the steps of the experiment are listed below. 5: geologic events 1. choose a student to represent the sun. the planets are represented by two tennis balls. 2. ask the student to hold the tennis balls in each palm and spin on the ice with arms stretched out. 3. ask the student to draw in the arms after about 10 spins. 4. observe the student's arms rotate faster when they are closer to the body. 05 geologic events enors) the experiment most likely demonstrates that (2 points) 07 discussion-based sessment/module planets exert gravitational force on the sun the sun exerts gravitational force on the planets 3.07 discussion-based ssessment speed of a planet depends on its distance from the sun new version available! (3.0.119) get it now submit 18.07: module exam description

Elizabeth has two separate samples of the same substance. sample is in the liquid state, and the other is in the solid state. the two samples most likely differ in which property?