Derivatives of Displacement Series by Jennifer Ellis

Fourteen-year-old Abbey Sinclair likes to spend her afternoons in the physics lab learning about momentum and gravitational pull. But her practical scientific mind is put to the test when her older brother, Simon, discovers a mysterious path of stones that allows them, along with Abbey’s twin, Caleb, to travel back and forth between their world and what appears to be...the future... moreFourteen-year-old Abbey Sinclair likes to spend her afternoons in the physics lab learning about momentum and gravitational pull. But her practical scientific mind is put to the test when her older brother, Simon, discovers a mysterious path of stones that allows them, along with Abbey’s twin, Caleb, to travel back and forth between their world and what appears to be...the future. Unfortunately, they’re not the only ones who know about the stones, and they soon realize their lives are in danger from a man known only as Mantis. Abbey, Caleb, and Simon must follow a twisting trail of clues that will lead them from their autistic neighbor, Mark, to a strange professor who claims to know the rules of the stones, and to multiple futures—some of whose inhabitants don’t want to stay put. It will take all of Abbey’s analytical skills to unravel the secrets of the stones, uncover the threads that tie the futures together, thwart Mantis’s plan, and, most importantly, keep her family alive—now and in the future. A Pair of Docks explores Einstein’s Theory of Relativity, the meaning of time, the potential for parallel universes, and the boundary between science and witchcraft. It is the first novel in the Derivatives of Displacement series. less

Abbey Sinclair would just like to return to her physics textbooks, but the witches who just moved in across the street seem to be up to something, and one of them has offered to give her lessons in witchcraft. She also has to decide what to do with the instructions on how to save the world that seem to have come from her future self.Meanwhile Mark is increasingly obsessed with a set of maps with strange markings that he received from Dr... moreAbbey Sinclair would just like to return to her physics textbooks, but the witches who just moved in across the street seem to be up to something, and one of them has offered to give her lessons in witchcraft. She also has to decide what to do with the instructions on how to save the world that seem to have come from her future self.Meanwhile Mark is increasingly obsessed with a set of maps with strange markings that he received from Dr. Ford, Caleb is still angry that Abbey will not tell him what happened in his future, and Simon has been caught hacking into the City Hall computer system.The adults of Coventry, or at least the ones with witchblood, seem once again quite willing to draw Abbey, Caleb, Simon, and Mark into their schemes, except this time the stakes are higher. Abbey and Mark race to unravel the secrets of the maps and the stones in advance of some of the less trustworthy adults, while trying to figure out who's on the good side... if there is a good side. less