What is energy?
The ability to do work or make change
Two basic kinds of energy
Kinetic- The energy of movement
Ex: roller coaster, mel moving her fingers in a weird fashion
Potential- stored energy
Ex: elastic band, parked car, food
Factors affecting kinetic energy:
Mass- the greater the mass=the greater the kinetic energy
Velocity- the faster the object=the greater the kinetic energy
Ex: Bowling ball vs golf ball
Factors affecting gravitational potential energy:
Height- the higher the object the more potential energy
Weight- the heavier the object the more potential energy
Shape (elastic potential)- the object can be stretched and return to its original shape
Forms of energy
Thermal- Kinetic-vibration of particles of an object
Electrical- potential/Kinetic- electrons move from atom to atom
Chemical- Potential - energy is stored in the chemical bonds of molecules
Nuclear- P- Energy stored in nucleus of atoms
Electromagnetic- Kinetic- energy moves in waves
Elastic- P -energy is released when an object is stretched and released
Sound- Kinetic- energy moves in waves
Energy Transformation-
Playing basketball- chemical->mechanical(movement)->potential->thermal
Cooking ramen- electrical->thermal
Using your the phone- electrical->sound->electromagnetic->thermal->chemical
Energy and Friction
Explain how the energy from a spinning top is transformed not lost. Where does the energy go?
- Mechanical energy is transformed into thermal energy- into the table and into air
Temperature- The AVERAGE kinetic energy of an object
Thermal energy- The TOTAL kinetic energy of an object.
Heat- The transfer of thermal energy
Which has more thermal energy?
A pool at 75F or a cup of water at 75F?
A 8oz cup of chocolate milk or a 8oz mug of hot chocolate?
An ice cube or a cup of coffee?
The Transfer of Heat
Conduction- transfer of heat through two objects touching
Convection- transfer of heat through liquid or gas
Radiation- transfer of heat through electromagnetic waves
Ex of each: Conduction- touching a hot pan
Convection- lava lamp
Radiation- tanning on the beach