## What's new in March 2017

DIY Conservation of Momentum - Recoil 1

- This interactive explores recoil (backward movement) arising due to conservation of momentum in a system. The activity involves an astronaut in deep space carrying a small portable cannon, designed to fire a cannonball at a specified velocity.

*HS-PS2-2: Use mathematical representations to support the claim that the total momentum of a system of objects is conserved when there is no net force on the system.**4-PS3-3: Ask questions and predict outcomes about the changes in energy that occur when objects collide.*

Electron Configuration using Periodic Table - Interactive Exerciser

- This interactive exerciser lets you practice writing electron configurations of atoms by referring to the periodic table. The exercise consists of 5 questions. Each question presents a randomly selected element for which you have to write the electron configuration.

*MS-PS1-1: Develop models to describe the atomic composition of simple molecules and extended structures.**HS-PS1-1: Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms*

Electron Configuration using Energy Levels Hierarchy Diagram

- This interactive exerciser lets you practice writing electron configurations of atoms by referring to a diagram denoting the hierarchy of energy levels and sub-levels. The exercise consists of 5 questions. Each question presents a randomly selected element for which you have to write the electron configuration. Using the energy levels hierarchy diagram to determine the sequence of filling the orbitals.

*MS-PS1-1: Develop models to describe the atomic composition of simple molecules and extended structures.**HS-PS1-1: Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms*

Orbital Diagram - Interactive Exerciser

- This interactive exerciser lets you practice constructing orbital diagrams for the selected element. The exercise consists of 5 questions. Each question presents a randomly selected element for which you have to construct the orbital diagram indicating the state of electrons in each orbital. Follow Hund's rule and construct the orbital diagram by clicking on the orbitals. Each click on the same orbital box progressively adds and removes the electrons in a sequence.

*MS-PS1-1: Develop models to describe the atomic composition of simple molecules and extended structures.**HS-PS1-1: Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms*

DIY Inelastic Collision 1

- This interactive involves a perfectly inelastic collision between two toy trains of specified masses, traveling with specified constant velocities in opposite directions. The activity consists of two trials enabling you to compare the inelastic collisions between the two toy trains, for different combinations of mass and velocity.

*MS-PS2-1: Apply Newton’s Third Law to design a solution to a problem involving the motion of two colliding objects.**HS-PS2-2: Use mathematical representations to support the claim that the total momentum of a system of objects is conserved when there is no net force on the system.**4-PS3-3: Ask questions and predict outcomes about the changes in energy that occur when objects collide.*