ACT Science

Independent Variable

The variable that the scientist changes. (For example, if you are changing fertilizer brands to see which causes the most plant growth, the independent variable is the fertilizer brand.)

Dependent Variable

the effect of the independent variable (For example, if you are changing fertilizer brands to see which causes the most plant growth, the dependent variable is the plant growth)

Control Group

the group that does not receive the independent variable.

Constant

A factor that stays the same across all test subjects and throughout the duration of the experiment

positive correlation

when two variables increase together or decrease together (also called direct variation)

negative correlation

when two variables change in opposite directions (one increases, the other decreases) (also called inverse variation)

pH range of acids

0-7 (7 is neutral)

pH range of bases (also called alkaline solutions)

7-14 (7 is neutral)

What reactants go into photosynthesis?

Carbon dioxide, water, and sunlight

What does photosynthesis produce?

glucose and oxygen

What is the equation for photosynthesis?

6CO2 + 6H20 + sunlight --> C6H12O6 + 6O2

What subatomic particles comprise the atomic nucleus?

protons and neutrons

What are the charges of protons, neutrons, and electrons?

Protons are positive, neutrons are neutral, and electrons are negative

What is the general principle of gravity?

Smaller objects are attracted to larger objects

Allele

different versions of a gene

Dominant traits

Traits that are expressed whenever their alleles are present

Recessive traits

traits that typically do not show in a person unless both genes for the trait are inherited (homozygous)

Heterozygous

An organism that has two different alleles for a trait

Homozygous

An organism that has two identical alleles for a trait

Genotype

An organism's genetic makeup, or allele combinations.

Phenotype

The physical characteristics of an organism (the physical result of the genotype. for example, brown hair)

Trait

A physical characteristic

How many millimeters are in a meter?

1000 millimeters

Amoeba

a unicellular organism with a nucleus

Law of Conservation of Mass

Matter is neither created nor destroyed

kinetic energy

the energy an object has due to its motion

potential energy

stored energy

catalyst

substance that speeds up the rate of a chemical reaction

Proton

Positively charged particle in the nucleus of an atom

Neutron

A small particle in the nucleus of the atom, with no electrical charge

Electron

negatively charged particle; located outside the atomic nucleus

Products

The elements or compounds produced by a chemical reaction.

Reactants

A starting material in a chemical reaction

Gametes

reproductive cells (sperm and egg)

Order of planets

Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

limiting reactant (reagent)

any reactant that is used up first in a chemical reaction; it determines the amount of product that can be formed in the reaction

Solubility

the ability of one substance to dissolve in another at a given temperature and pressure

Genus

group of closely related species; the first part of the scientific name in binomial nomenclature

Species

A group of similar organisms that can breed and produce fertile offspring; the second part of the scientific name in binomial nomenclature

chemical reactivity

Tendency of a substance to engage in chemical reactions.

cellular respiration

Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

erosion and weathering

Processes by which rock, sand, and soil are broken down and carried away

How many milliliters are in a liter?

1000

percent error formula

|accepted value-measured value| / accepted value x100

Predator vs. Prey

A predator is an organism that eats another organism. The prey is the organism that the predator eats.

What does a balance measure?

mass

What does a graduated cylinder measure?

volume

What does a pH meter measure?

pH

What does a light microscope allow you to measure?

You can use it to count anything that is too small to see with the naked eye.

What does a thermometer measure?

temperature

What does a metric ruler measure?

length

What does a calorimeter measure?

change in thermal energy (calories)

negative slope

falls from left to right

positive slope

rises from left to right

What is a telescope used for?

to help see far away objects

Density

mass/volume

melting point

The temperature at which a solid becomes a liquid

boiling point

The temperature at which a liquid changes to a gas

Condensation

The change of state from a gas to a liquid

Evaporation

The change of state from a liquid to a gas

Conductivity

The ability of an object to transfer heat or electricity to another object.

Resistivity

A material's opposition to the flow of electric current.

amino acids

building blocks of proteins

fatty acids

Building Blocks of Lipids

Monosaccharides

simple sugars

nucleotides

Basic units of DNA molecule, composed of a sugar, a phosphate, and one of 4 DNA bases

What is the equation for force?

Force = mass x acceleration

What should you do if one of the answer choices is cannot be determined?

Proceed with caution! Double check the units of measure in the answers and on the graph to make sure they correspond. Cannot be determined is sometimes the answer but not always.

What kinds of cells have cell walls?

Plant cells and fungi (NOT animal cells)

sex-linked traits

Traits controlled by genes located on sex chromosomes.

How does temperature affect kinetic energy and molecular speed?

As temperature increases, kinetic energy and molecular speed both increase as well.

Autotroph

An organism that makes its own food (plants)

Cellulose

A substance (made of sugars) that is common in the cell walls of many organisms

Cholesterol

A lipid that forms an essential component of animal cell membranes

Producer

An organism that makes its own food

Consumer

An organism that eats other organisms (also known as a heterotroph)

detritivores/decomposers

consumers that feed on dead organic matter

How many milligrams are in a gram?

1000

haploid vs diploid cells

Haploid have 1 copy of each chromosome - gametes. Diploid have 2 copies of each chromosomes - somatic (body) cells.

What is the relationship between frequency and wavelength?

As frequency increases, wavelength decreases.

Significant Digit Rules

1. non zero numbers are always significant

2. zeros between non zero numbers are always significant

3. all final zeros to the right of the decimal place are significant

4. Placeholder zeros are not significant

5. counting numbers and defined constants have an infinite number of significant figures

What should you do if you see an abbreviation or an organism's Latin name (italics)?

Write the full name next to the abbreviation (paper towels next to PT) or label it with the common name (for example, write tomato plant next to Solanum lycopersicum)

What is the best approach to the science section?

Read the passage once and underline important terms. Be on the lookout for abbreviations and Latin names.

Take a look at what is being measured in the charts and graphs.

When you get to the questions, mark and point! Circle where the question tells you to go and key details you will need when you get to that chart or graph. Use your other hand to point to each spot as you break down the question.

If you get lost reading the question, always read the answer choices to see if they help clarify.

Eliminate, eliminate, eliminate.

inconsistent

not in agreement

Metric System Conversions

• To convert larger unit to smaller unit, move decimal point to right

• To convert smaller unit to larger unit, move decimal point to left

- 1 kilogram = 1,000 grams

- 1 gram = 1,000 milligrams

Remember King Henry Died Drinking Chocolate Milk (see image).

endotherm

An animal whose body controls and regulates its temperature by controlling the internal heat it produces (mammals are endotherms)

What is the difference between a reptile and an amphibian?

Reptiles have dry, scaly skin, breathe with lungs from birth, and lay shelled eggs on land, while amphibians have moist, permeable skin, often start with gills in water, and lay jelly-like eggs in water.

Melting point of ice

0 degrees Celsius

Boiling point of water

100 degrees Celsius

What is the relationship between density and buoyancy?

an object floats if it's less dense than the fluid it's in, sinks if it's denser, and remains suspended if densities are equal

solvent

the substance in which the solute dissolves

solution

A mixture that forms when one substance dissolves another.

aqueous

dissolved in water

alloy

A mixture of two or more metals

polymer

large compound formed from combinations of many monomers

element

A pure substance made of only one kind of atom

How does pressure affect the movement of a gas or liquid?

gas and liquids travel from high pressure to low pressure

viscosity

A liquid's resistance to flowing

organ

A collection of tissues that carry out a specialized function of the body

combustion

A rapid reaction between oxygen and fuel that results in fire