Transcript Science PSSA - DuBois Area School District

Science PSSA
Keys to success
Scientific Method
What is “testable”
 Good investigations/experiments have a
control and variables
 Sample size matters
 Be able to interpret graphs
and charts

Systems and Cycles

Open loop systems
◦ Allow energy and mass in and out
◦ Water cycle (ocean), Rock cycle (volcano),
Nitrogren cycle (soil), Carbon cycle (animal)

Closed loop systems
◦ Allow energy in and out but not mass
◦ Earth, thermostat
Systems & Cycles
Energy is cycled through the universe in
an open loop
 Matter is cycled through the Earth in a
closed loop (Earth is a closed system)

Laws

Law of conservation of energy
◦ Energy cannot be created or destroyed (it can
be transformed)

Law of conservation of matter/mass
◦ Matter/mass is always conserved
Human effects on environment
Renewable and nonrenewable energy
sources
 Fossil fuels
 Agriculture

◦ IPM
Genetics
DNAchromosomesgenes
allelestraits
 Genotypes – alleles or genes for a trait

◦ Can be dominant or recessive
Phenotypes – physical appearance
 Punnett Squares

Punnett Square
Genotypes: Aa
Phenotypes: all Red
Ecology & Ecosystems
Energy flows from producers to
consumers to decomposers
 Food webs and trophic pyramids are used
to show energy flow
 Know:

◦ Succession
◦ Predator, prey
and competitor
Adaptation & Evolution

Adaptations increase an organism’s
chance of survival
◦ Camoflauge
All organisms evolve – change – it is
called natural selection
 Humans use selective breeding to change
traits in animals

Chemistry
In a chemical change you get a new
substance
 The periodic table groups elements by
their properties

Forces
Balanced forces do not affect an object’s
motion
 Unbalanced forces do affect an object’s
motion
 Simple machines make work easier by
increasing the mechanical advantage –
changing the size or direction of a force

Geology
Rocks are either igneous, sedimentary or
metamorphic and can change into one
another in the rock cycle.
 Landforms are made by plates colliding or
separating, volcanoes, earthquakes,
glaciers, erosion etc.

Water & Weather
Watershed – area that drains into a body
of water
 Wetland – swampy area good at filtering
pollution
 Ocean currents influence land climates
 High pressure – clear skies
 Low pressure – cloudy and rainy
 Salt water is more dense than fresh

Convection Currents cause:
Warm air to rise and cold to sink in the
atmosphere (changes weather, causes Global
winds)
 Warm water to rise and cold to sink in the
ocean (causes density currents)
 The movement of magma in the asthenosphere
(causes lithospheric plates to move)

Clouds
Solar System
Earth’s tilt and revolution create seasons
 Moons phases are caused by moon
revolving around the Earth
 Know Solar and Lunar eclipses
 All objects in the universe have gravity
(Law of Universal Gravitation)
