1. Types of Interactions

2. Magnetic Interaction Examples
Magnet repelling another magnets
Magnet attracting iron nails
Magnet attracting the refrigerator

3. Electric Charge Interaction Examples
Lighting is built up static electric charge. The charged clouds attract other objects
A balloon rubbed on someone’s head creates electric charge. Hair attracted to the balloon is an electric charge interaction
An electrically charged wand picks up uncharged pieces of paper

4. Light Interaction Examples
A light bulb illuminates objects because the filament gets very hot. Making other objects light up is a light interaction.
Laser pointers light up very specific places.
The sun gives the earth light and heat through a light interaction.

5. Electric Circuit Interaction Examples
Electric scooters use electric circuit interactions to make the wheels spin.
The current flowing through the wires to light the light bulb is an electric circuit interaction.
A truck with a dead battery is connected to another truck. The electricity that flows between them is an electric circuit interaction

6. Energy Diagrams
Scientists describe how energy is transferred from the energy source to the receiver.
The soccer player transfers some of her energy to the ball when she kicks it.
Energy is not created. It is only transferred from another object.

7. Energy Diagrams
Good energy diagrams will clearly label the energy source, the receiver, and the type of interaction which is responsible for the energy transfer.

8. Energy Chains
Many energy transfers do not take place in single steps. They can be written as interaction chains.

9. Types of Mechanical Interactions
Friction Interaction- Two solid surfaces rubbing together.
Friction creates thermal energy
Ice is a low friction surface

10. Types of Mechanical Interactions
Applied interaction- two solid (non-elastic) objects pushing or pulling on each other.
A wrecking ball hitting a building is mostly an applied interaction
Boy pushing a car is an applied interaction

11. Types of Mechanical Interactions
Drag Interaction- an object moving through a fluid (gas or liquid). The fluid acts to slow down the object.
A plane moving through air has a drag interaction
The boat moving through water has a drag interaction

12. Types of Mechanical Interactions
Elastic Interaction- Two objects push or pull each other AND one is stretched or compressed.
The tennis ball hitting the racket shows two elastic interactions. The ball is compressed (flattened out on one side) while the racket strings are stretched.

13. Energy Transfer
Energy is not created or destroyed, only transferred from one object to another.
This means that during an interaction the energy source will ALWAYS lose some type of energy.
The energy receiver will ALWAYS gain some type of energy.
Source- decreases
Receiver- increases