Year 10 Semester 2 Science Exam Revision

convert km/h to m/s

divide by 3.6

convert m/s to km/h

multiply by 3.6

describe acceleration

the measure of the change in velocity

calculate acceleration

change in velocity divided by time taken

describe speed

the rate of change of distance over time

describe velocity

the speed of something in a given direction

describe distance

a measure of how far an object has travelled

calculate speed

distance travelled divided by time taken (d/t)

calculate velocity

displacement divided by time taken

calculate distance

measured in metres

calculate displacement

measure how far the object is from the origin in metres and provide a direction (if at an angle, find angle from a bearing of true North)

define scalar quantity

magnitude

define vector quantity

magnitude and direction

describe displacement

an object’s overall change in position in a certain direction

this symbol means: Δ

change

What is Newton’s first law of motion?

Inertia - an object remains at rest or in motion (at a constant speed and direction) until acted on by an unbalanced force

What is Newton’s second law of motion?

F (force in newtons or N) = m (mass in kg) x a (acceleration in m/s²)

(the acceleration of an object is directly proportional to the net force acting on it, and inversely proportional to the mass of that object)

What is Newton’s third law of motion?

for every action there is an equal but opposite reaction

What is binomial nomenclature?

Literally meaning two name, it is the system of scientifically naming species. The scientific name of a species is their genus (capitalised) and species (not capitalised), this is written in italics and once already used the genus is abbreviated to a capital letter and dot. For example tiger in binomial nomenclature is Panthera tigris, when this is shortened it become P. tigris.

What is the hierarchy of the classification of living things?

domain(archaea, bacteria and eukarya), kingdom, phylum, class, order, family, genus and species

What is the process of evolution by natural selection?

1. variation in traits, some better increase individuals’ chances of survival

2. members with more favourable traits are more likely to survive and pass traits on

3. individuals reproduce and traits are passed on

4. overtime the organisms in the species possess traits that better help them survive

Define precision

measure of repeatability of scientific measurements; how close two or more measurements are to each other (the range between them)

Define repeatability

how similar the results of successive measurements of the same quantity being measured carried out under the same conditions of measurement are

Define accuracy

something considered accurate if it is close to the true value of the quantity being measured (the value that would be found if the quantity could be measured perfectly)

Describe the contribution of Charles Darwin in the study of evolution

Darwin proposed his Theory of Natural Selection: that organisms with advantageous traits survive and reproduce. 

Describe the contribution of Jean-Baptiste Lamarck in the study of evolution

Lamarck proposed the his Theory of Inheritance of Acquired Characteristics. He believed traits developed during life could be passed on. This was disproven, but is still historically important.

Selection pressures meaning

Environmental factors that affect survival/reproduction.

What are the types of selection pressures?

predation, competition, climate, disease and human impact

Define speciation

the formation of new and distinct species in the course of evolution

Describe the process of speciation due to geographic barrier

A geographic barrier creates geographic isolation, separating populations of a species. There is no gene flow meaning independent evolution to new selection pressures. These accumulated differences create a new species.

What are the types of evidence for evolution?

fossils, comparative anatomy, molecular biology, embryology and biochemistry

(Five Clues Make Evolution Believable)

What are the mechanisms of evolution? (indicate which are causes of individual variation [i] and which are causes of population variation [p]

mutation [i] [p], gene flow [p], genetic drift [p], natural selection [p] and sexual reproduction [i]

Define convergent evolution

species from different ancestors evolve to have similar traits (e.g., shark & dolphin fins)

Define divergent evolution

related species evolve to have different traits (e.g., Darwin’s finches)

Define homologous structures

same structure, different function - common ancestor (e.g., human arm and bat wing)

Define analogous structures

Different structure, same function - no common ancestor (e.g., bird wing & insect wing)

Describe human impact on biodiversity

Human’s use of reproductive technologies (e.g. artificial selection, cloning) can disrupt natural biodiversity. These technologies are used in agriculture, horticulture, and animal breeding to pass on desired traits. This reduces variation in traits, limiting species’ ability to evolve

What are the four types of chemical reactions?

synthesis, decomposition, single displacement and double displacement

What are different factors that effect the rate of reactions?

temperature (higher temperature → faster reaction (more kinetic energy)), concentration (higher concentration → more collisions), surface area (smaller particles → faster reaction), catalysts (lower activation energy → faster reaction), and pressure (gases) (higher pressure → faster reaction)

What is the law of conservation of mass?

the total mass of reactants equals the total mass of products, mass cannot be destroyed or created

What are the states of matter written in brackets for chemical equations?

solid (s), liquid (l), gas (g), aqueous (aq)

Define synthesis as a chemical reaction

Two or more substances combine to create one product.

Define decomposition as a chemical reaction

one compound breaks down into simpler substances

Define single displacement as a chemical reaction

One element replaces another in a compound.

Define double displacement as a chemical reaction

Two compounds exchange ions.

Describe the evidence for evolution fossils

Fossils are formed when an individual dies and is covered in dirty/ice due to weather changes. The study of fossils (also known as palaeontology), uses the stratification of rock layers to determine a time sequence of events (relative dating) and measures the number of radioisotopes in the fossil and the speed of their radioactive decay to calculate an accurate fossil age (absolute dating).

Describe the evidence for evolution comparative anatomy

homologous structures indicate common ancestry

Describe the evidence for evolution molecular biology

similar DNA sequences show relatedness

Describe the evidence for evolution embrology

similar early development stages

Describe the evidence for evolution biochemistry

comparing the biochemical make-up (such as proteins) of organisms

Describe the mechanism for evolution mutation

new genetic variation

Describe the mechanism for evolution genetic flow

movement of genes between populations

Describe the mechanism for evolution genetic drift

random changes in small populations

Describe the mechanism for evolution natural selection

non-random survival of advantageous traits

Describe the mechanism for evolution sexual reproduction

recombining genes during fertilisation

Define artificial selection

non-natural, intentional process where humans breed organisms for specific traits

Explain car safety features in relation to Newton’s laws

Seatbelts: Apply force to stop passengers (First Law)

Crumple Zones: Absorb energy and reduce force (Second Law)

Airbags: Increase time of impact to reduce acceleration and force (Second Law)

Headrests: Prevent whiplash by counteracting motion (Third Law)

Provide information about interpreting displacement-time graphs

positive slope = moving away from starting position (origin – O)

negative slope = moving back towards starting position

slope = velocity

steeper slope = higher speed

horizontal line = no movement

Provide information about interpreting velocity-time graphs

positive slope = accelerating (velocity increasing)

negative slope = decelerating (velocity decreasing)

slope = acceleration (steeper slope = greater acceleration)

area under graph = displacement

Explain random errors

unpredictable variations in the measurement process, resulting in a spread of readings and affecting the precision of a measurement

Explain systematic errors

cause measurement to consistently differ from the truth value in the same way each time

Explain mistakes

mistakes or personal errors, should not be includes in a report, an experiment should be repeated correctly to overcome mistakes