SCIENCE TO KNOW/REVIEW
WATER CYCLE
The Water Cycle (also known as the hydrologic cycle) is the journey water takes as it
circulates from the land to the sky and back again.
The Sun's heat provides energy to evaporate water from the Earth's surface (oceans,
lakes, etc.). Plants also lose water to the air (this is called transpiration). The water
vapor eventually condenses (condensation), forming tiny droplets in clouds. When
the clouds meet cool air over land, precipitation (rain, sleet, or snow) is triggered,
and water returns to the land (or sea). Some of the precipitation soaks into the
ground. Some of the underground water is trapped between rock or clay layers; this
is called groundwater. But most of the water flows downhill as runoff (above ground
or underground), eventually returning to the seas as slightly salty water.
The atom
FOOD CHAIN VS FOOD WEB
The arrows in a food chain show the flow of energy, from the sun or
hydrothermal vent to a top predator. As the energy flows from organism to
organism, energy is lost at each step. A network of many food chains is called
a food web.
Food chain:
1. Primary producers (organisms that make their own food from sunlight and/or chemical energy
from deep sea vents) are the base of every food chain - these organisms are called autotrophs.
2. Primary consumers are animals that eat primary producers; they are also called herbivores
(plant-eaters).
3. Secondary consumers eat primary consumers. They are carnivores (meat-eaters) and
omnivores (animals that eat both animals and plants).
4. Quaternary Consumers eat Tertiary Consumers
5. Food chains "end" with top predators, animals that have little or no natural enemies.
FOOD WEB
The Scientific Method
1. State the problem
2. Collect data
3. Form an hypothesis (if, independent variable (what changes), then, dependent
variable)
4. Design experiment
5. Form a conclusion (has hypothesis proven based on results of experiment?)
A good experiment has only one independent variable and several constants and trials
Experimental Design example:
1. The independent variable is the variable that is intentionally changed in the
experiment, such as the temperature of the water in which an effervescent tablet
was dissolved.
2. The dependent variable is the variable that responds to the changes in the
independent variable. For example, the time it takes for the tablets to dissolve in
the different temperatures of water is the dependent variable.
3. The control is the standard against which the researcher compares the results
from each treatment group (level) in the experiment. For example, the control
might be the room temperature water, which is about 20° C. In many cases, there
will not be a true control.
4. The repeated trials are the number of times the experiment is repeated to
determine how the independent variable affected the results. One complete
experiment is one repeated trial. For example, one tablet is dissolved in 10°
water, one in 20° water, one in 30° water, one in 40° water, and one in 50° water
so that 5 tablets total are used. This is ONE repeated trial because it makes
ONE complete experiment. If the researcher tried dissolving a tablet seven
different times in each temperature of water, he/she would have seven repeated
trials. If 10 different plants are used for each treatment, then there are 10
repeated trials.
5. Constants are the things that are kept the same each time one of the trials in the
experiment is repeated. For example, constants could include the amount of
water used, the brand of effervescent tablet used, the type of water used, and the
fact that the water was not stirred. As many outside factors as possible should be
kept constant in an experiment so that the researcher can be sure that any
changes that occur do so because of the independent variable.
Genetics
The Punnett square is a diagram that is used to predict an outcome of a particular
cross or breeding experiment. It looks like a window pane. Capital letters are dominant
genes (alleles) and small letters are recessive genes or traits.
Purebreds(homo) have like alleles; hybrids(hetero) have different alleles
A chromosome pair homozygous for a gene will have the same allele for that gene on
each chromosome. A chromosome pair heterozygous for a gene will have different
alleles on each chromosome
A critical feature of DNA(deoxyribonucleic acid) is the ability of the nucleotides to make
very specific pairing.
A-T and C-G.
A is said to be complementary to T and C is complementary to G
BALANCING CHEMICAL EQUATIONS
A chemical equation is a written symbolic representation of a chemical reaction.
The reactant chemical(s) are given on the left-hand side and the product
chemical(s) on the right-hand side
reactantproduct
The law of conservation of mass states that no atoms can be created or destroyed in a chemical
reaction, so the number of atoms that are present in the reactants has to balance the number
of atoms that are present in the products (always leave hydrogen and oxygen for last)
Balancing equations:
Ex:
C3H8 + ?O2 --> ?H2O +3CO2

The coefficient 3 in front of carbon on the right side indicates 3 carbon atoms just as the
subscript 3 on the left side indicates 3 carbon atoms.
In a chemical equation, you can change coefficients, but you must never alter the subscripts
1. Balance the hydrogen atoms: You have 8 on the left side. So you'll need 8 on the right side.
C3H8 + ?O2 --> 4H2O +3CO2

On the right side, you now added a 4 as the coefficient because the subscript showed
that you already had two oxygen atoms

When you multiply the coefficient 4 times by the subscript 2, you end up with 8.
2. Balance the oxygen atoms:
 Because you've added coefficients to the molecules on the right side of the equation,
the number of oxygen atoms has changed. You now have 4 oxygen atoms in the water
molecule and 6 oxygen atoms in the carbon dioxide molecule. That makes a total of 10
oxygen atoms.
 Add a coefficient of 5 to the oxygen molecule on the left side of the equation. You now
have 10 oxygen molecules on each side.
C3H8 + 5O2 --> 4H2O + 3CO2.
The carbon, hydrogen, and oxygen atoms are balanced. Your equation is complete!
Photosynthesis Equation: 6CO2 + 6H2O ------> C6H12O6 + 6O2
Sunlight energy
Formulas and other misc you might see
Specific heat capacity
q = mcΔT
q = heat energy (joules)
m = mass (grams)
c = specific heat capacity (J/g·°C or K)
ΔT = change in temperature (K or C)

Example: What is the heat in Joules required to raise the temperature of 25 grams of
water from 75 °C to 100 °C? What is the heat in calories?
Needed information: specific heat of water = 4.18 J/g·°C
4.18 Joules = 1 calorie
q = (25 g)x(4.18 J/g·°C)[(100 °C - 75 °C)]
q = (25 g)x(4.18 J/g·°C)x(25°C)
q = 2612.5 Joules

For heat in calories, you need to convert Joules to calories.
10450/4.18 = 625 calories
Force = Mass x Acceleration or F=MA : when mass is doubled, acceleration is halved
Density = ___Mass___
Volume
Mass = Density x Volume
KHDMDCM – metric units of measure
Kilo, Hecto, Deco, Meter(base), Deci, Centi, Milli…(M M Micro)
King Henry Died, Mother Didn’t Care Much
Familiarity with interpreting the periodic table
Scientific notation
mean/median/mode/range
Definitions to know
Photosynthesis: the process by which green plants and some other organisms use sunlight to synthesize
foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment
chlorophyll and generates oxygen as a byproduct. Animals use the process called cellular respiration.
6CO2 + 6H2O ------> C6H12O6 + 6O2
Sunlight energy
Homeostasis: the ability or tendency to maintain internal stability in an organism to compensate for
environmental changes.
Mitosis: a type of cell division that results in two daughter cells each having the same number and kind of
chromosomes as the parent nucleus, typical of ordinary tissue growth
Meiosis: a type of cell division in which a nucleus divides into four daughter nuclei, each containing half
the chromosome number of the parent nucleus: occurs in all sexually reproducing organisms in which
haploid gametes or spores are produced
Solubility: The quality or condition of being soluble(capable of being dissolved); or the amount of a
substance that can be dissolved in a given amount of solvent.
Biome: A major regional or global biotic community, such as a grassland or desert, characterized chiefly
by the dominant forms of plant life and the prevailing climate
fossil fuels: fuel, such as coal, oil, or natural gas formed from the decayed remains of prehistoric(ancient)
animals and plants – a finite source
fracking: the procedure of creating fractures in rocks and rock formations by injecting fluid into cracks to
force them further open. The larger fissures allow more oil and gas to flow out of the formation
Blood flow
Once blood travels through the pulmonic valve, it enters your lungs. This is called pulmonary circulation.
From your pulmonic valve, blood travels to the pulmonary artery to tiny capillary vessels in the lungs.
Here, oxygen travels from the tiny air sacs in the lungs, through the walls of the capillaries, into the
blood. At the same time, carbon dioxide, a waste product of metabolism, passes from the blood into the
air sacs. Carbon dioxide leaves the body when you exhale. Once the blood is purified and oxygenated, it
travels back to the left atrium through the pulmonary veins
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Arteries are blood vessels that carry away from your heart
Veins are blood vessels that carry blood toward your heart
Waxing (getting bigger) vs waning (getting smaller)
Tides occur because of the pull of gravity of the moon and the sun on the Earth's
oceans. Because the moon is closer to the Earth, it has the greatest effect on our tides.
There are approximately 2 high tides and 2 low tides every 24 hours as well as two
spring(strong) tides and two neap(weak) tides every month.
Earth’s rotation vs. orbit around the sun:
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the earth rotates around its axis every 24 hours which produces day and night
the earth orbits and revolves around the sun every 365 1/4 days. (1 year)
the combined effect of the earth’s orbital motion and the tilt of its rotation axis
results in the seasons. When the earth axis points away from the sun, winter can
be expected for that hemisphere and vice versa
opposite hemispheres have opposite seasons