Science Flashcards
Scientific method
Question Hypothesis Experiment Data Conclusion Retest/refine
The variable that you decide to change
Independent variable
The variable that changes as a result
Dependent
The variables that must NOT change
Control variable
A description of how close a measurement is to the true value of the quantity measured
Accuracy
The exactness of measurement
Precision
Anything that has mass and volume
Matter
Taking up space
Volume
Same throughout
Ex. Chocolate ice cream & tomato soup
Homogeneous
Samples may be different
EX. Rocky road ice cream & chicken noodle soup
Heterogeneous
Found on the periodic table
EX. Hydrogen carbon silver
Element
Two or more elements put together EX. H2O
Compound
Movement of molecules in the three phases of matter
A. Solid
B. Liquid
C. Gas
A. Molecules vibrate but can’t switch places
B. Molecules move over and around each other
C. Move randomly throughout the container
How tightly molecules are packed
Density
Formula for density
D=mass/volume
Positive, found in the nucleus, and equal to the atomic #
Protons
Neutral, found in the nucleus, and equal to the mass # - the atomic #
Neutrons
Negative, found in the electron cloud, and equal to the atomic #
Electron
Atoms of the same element with different numbers of neutrons
Isotopes
The electrons in the outer energy level
Valence electrons
These elements don’t react because they are already stable
Noble gases
All elements want ______ valence electrons
8
Most atoms are ___________ unless they bond
Unstable
2 non-metals; share electrons
Covalent bonds
A metal and a non-metal; transfer electrons
Ionic bond
An atom that has gained or lost electrons and has an electrical charge
Ion
All compounds have a charge of _______.
0
Valence electrons and oxidation
Valence electrons is the outer energy level and oxidation is the charge
Columns on the periodic table; same # of valence electrons; same oxidation #
Group
Rows on the periodic table; same # of energy levels
Periods
Breaking, cutting, melting
Physical change
Burning, baking, rusting
Chemical change
Uses energy; gets colder
Endothermic
Produces energy; gets hotter
Exothermic
Speed and direction
Velocity
A change in speed or direction
Acceleration
An action that has the ability to change motion
Force
Objects tend to resist changes in motion
Inertia
Equation associated with newtons 2nd law
F=mxa
The strength of a objects motion
Momentum
Stored energy
Potential
Energy in motion
Kinetic
Energy can not be created or destroyed
Law of conservation of energy
A disturbance that carries energy
Wave
Waves are usually caused by _______.
Vibrating objects
___________ wave requires a medium
Mechanical
___________ wave doesn’t require a medium
Electromagnetic
The time it takes a complete wave oscillation to occur
Period
of cycles per unit of time
Frequency
All current MUST go through each part of the circuit; a single pathway
Series circuit
Must have at least one branch point
Parallel circuit
FORMULAS
Volume=l x w x h
Density= mass/volume
Speed=distance/time
Force=m x a
Potential energy= mgh
Kinetic energy= m x v2
-------
2
Wave speed= frequency x wavelength
