Notes for 12/3/07
Atoms
All matter is made of atoms.
Atoms are made of three main parts. The nucleus is at the center of the atom and it contains protons and neutrons.
Electrons are little parts that move around the nucleus of the atom.
Protons are positively charged.
Neutrons are neutral.
Electrons are negatively charged.
Everyday Forces
There are 3 forces that affect us everyday. They are friction, magnetism, and gravity.
Friction produces heat, like rubbing your hands together. Friction allows us to walk and a car to stop at the stop sign.
Magnetism is used in electronics and other motors. Magnets have 2 poles, the north and south poles.
Like poles repel(south repels south, north repels north). Opposite poles attract(north attracts south).
Gravity is what holds things down on earth, including us.
These forces act in pairs all the time. (For every action there is an equal and opposite reaction).
Harcourt Science 2000, E38-E39, F6-F8
Notes for 12/7& 12/10
Orbits and Inertia
An orbit is the path one body in space takes as it revolves around another body.
Rotate means to spin.
Revolve means to travel in a closed path around an object such as Earth does as it moves around the sun.
Inertia is the property of matter that keeps it moving in a straight line or keeps it at rest.
Different Kinds of Energy
Energy is the ability to cause changes in matter.
Potential energy is the energy an object has because of where it is or because of its condition.
Elastic potential Energy is the potential energy stored in a stretched rubber band.
Gravitational Potential Energy is the potential energy stored when a roller coaster is at the top of the hill.
Chemical energy is the potential energy stored in leaves because of photosynthesis.
Kinetic Energy is the energy of motion or energy in use.
Mechanical Energy is the kinetic energy that moving objects have.
Thermal Energy is the kinetic energy when the movement of molecules makes heat.
Electric Energy is the kinetic energy caused by the movements of electrons.
Light Energy is the kinetic energy of light waves that move from an object to your eyes.
Sound energy is the kinetic energy made by vibrations.
Energy Can Change Forms
A flashlight begins with chemical energy in the batteries. It uses that energy to produce electric energy when the switch is turned on. The electric energy then produces light and heat energy. An energy transfer drawing of the flashlight would be:
Chemical -> Electric -> Light -> Heat
Source, Harcourt Science, 2000
Notes for 12/14/07