8th GRADE SCIENCE MCA REVIEW QUESTIONS & ANSWERS

These questions are designed to help you do your best on the 8th GRADE SCIENCE MCA. They are based off of the specifications determined by the state of Minnesota. Most of the topics on the test have been covered in your science classes, however, there may at times be information you are unfamiliar with. Try your best! Use your test taking skills!

Answers follow questions.

Nature of Science and Engineering:

  1. What’s the difference between science and engineering?
  2. Science is used to explain and answer questions and engineering is used to improve things or make life easier.
  3. What is meant by “bias”?
  4. a preconceived opinion or feeling about a topic
  5. What is meant by “mean”, “median” and “mode”?
  6. Mean = average
  7. Median = the middle number in a series
  8. Mode = the most common number in a series
  9. What’s the difference between fact and opinion?
  10. A fact is true for everyone. An opinion is how one person feels or thinks.
  11. Can every question be investigated scientifically?
  12. No.
  13. What is a theory?
  14. An idea support by facts that cannot be absolutely proven true/false.
  15. What is a hypothesis?
  16. A possible answer to a scientific question.
  17. What is a controlled experiment?
  18. An experiment in which only one variable is changed.
  19. What is meant by controlled variable? Changed (manipulated) variable? Measured variable?
  20. Controlled = kept the same throughout the whole experiment
  21. Changed = the variable that is being tested, only ONE
  22. Measured = the data that is collected in the experiment
  23. Why is it important to only change one variable at a time?
  24. So that you know what is actually causing the difference I the results.
  25. How many trials should a good experiment have?
  26. At least 3
  27. What is meant by an open system and a closed system?
  28. Open = matter/mass can escape out into the surrounding environment
  29. Closed = no interaction outside the system, all matter/mass is contained
  30. What’s the difference between a scientific experiment and an engineering project?
  31. An experiment tests a hypothesis to see if it is correct or not, the result is an answer.
  32. A project takes an idea and creates a product, sometime going back and making improvements or design changes along the way.
  33. What are the basic SI (metric) units for measuring length? Volume? Mass? Temperature?
  34. MeterLiterGramCelsius degree
  35. Know how to convert between units. (Kilo Hecto Deka Unit Deci Centi Milli)
  36. Count the “jumps” on the “hill” and move the decimal the same direction and number
  37. What tool should you use to measure length? Volume? Mass? Temperature?
  38. Meter stick or rulerGraduated CylinderScale or BalanceThermometer
  39. What is the difference between mass and weight?
  40. Mass does not change with location – Weight considers gravity and changes with it

Physical Science:

MATTER:

  1. What is density? Formula?
  2. The amount of mass (matter) in a given space D = m/v
  3. What is dissolving?
  4. One substance is absorbed into another but the two are not chemically combined
  5. What is compression?
  6. Change in pressure of a substance as the particles get closer together
  7. What is diffusion?
  8. Process by which particles spread out from areas of high to low concentrations
  9. What is thermal expansion?
  10. Heat energy causes particle to speed up and move farther apart
  11. What is an element?
  12. Simplest form of a pure substance
  13. How are metals and non-metals different?
  14. Metals are shiny, malleable, ductile and reactive. Non-metals are not.
  15. What is a compound?
  16. Two or more elements chemically combined
  17. What is a chemical equation?
  18. A representation of a chemical reaction
  19. What is the difference between a mixture and a pure substance?
  20. Mixture is two or more substance NOT chemically combined. Pure substance is one element or compound.
  21. What is a physical change? Give examples.
  22. Change in the appearance or phase of the substance, same substance
  23. Change in size, shape, phase (solid, liquid, gas), number of pieces, color, dissolving
  24. What is the Law of Conservation of Mass?
  25. The total mass of a system is always the same. Mass is neither created nor destroyed.
  26. Describe the states or phases of matter using a particle model.
  27. What is a chemical change? Give examples.
  28. Change that results in a new substance or substances being produced.
  29. Burning, rusting , rotting, vinegar & baking soda, starch and iodine
  30. What are some differences between acids and bases? Give an example of each.
  31. Acids – taste sour, corrosive, pH 1-6, turn blue litmus RED – lemons, vinegar
  32. Bases – taste bitter, feel slippery, pH 8-14, turn red litmus BLUE – soap, cleaners

MOTION:

  1. What is the formula for calculating speed?
  2. Speed = distance divided by timeS=d/t
  3. When graphing speed, what component goes on the x-axis? The y-axis?
  4. X-axis = timey-axis = distance
  5. What is a force?
  6. A push or a pull
  7. What are balanced forces?
  8. Forces acting on an object that are equal is size but in the opposite direction, object does not change movement
  9. What are unbalanced forces?
  10. Forces acting on an object that are not equal in size but are in the opposite direction, object moves in the same direction as the greatest force
  11. How do forces acting on an object affect motion?
  12. Balanced = no movement or continues motion at same speed and direction
  13. Unbalanced = change in speed or direction in same direction as greatest force
  14. How does the sum of the forces working on an object affect its motion?
  15. Forces in the same direction add together
  16. Forces in opposite directions cancel each other out
  17. What are some forces that can act on an object from a distance?
  18. Magnetic, electrical, gravitational

ENERGY:

  1. What is being transferred (moved) by waves?
  2. Energy only – NOT MATTER
  3. What is the speed of a wave?
  4. How far a specific point on the wave traveled in a given time.
  5. What is the wavelength of a wave?
  6. Length between two consecutive identical troughs or crests
  7. What is the frequency of a wave?
  8. Number of vibrations in a given time – number of crests/troughs past a specific point in a given time
  9. What is the amplitude of a wave?
  10. Distance the wave moves from its resting point
  1. How is energy transferred through sound waves?
  2. Vibrations of a medium. Sound needs to travel through matter
  3. What is reflection?
  4. Light waves bouncing off of a surface – angel in equals angle out
  5. What is refraction?
  6. The bending of a light wave as it passes from one medium to another – example: air to water; object appears in a different spot than it actually is
  7. What is the color spectrum?
  8. White light through a prism breaks into the colors of the rainbow – ROY G BIV
  9. What is potential energy?
  10. Energy due to the position of an object – higher equals more potential energy
  11. What is kinetic energy?
  12. Energy of motion – faster moving equals more kinetic energy
  13. When would potential energy become kinetic energy?
  14. P.E. becomes K.E. when an object that was at rest begins moving
  15. What is thermal energy?
  16. The kinetic energy of moving particles (heat) – more movement = more energy
  17. What is electrical energy?
  18. Flow of electron from one place to another
  19. What is chemical energy?
  20. Potential energy stored in reactants – usually changes to heat or light when given off
  21. What is mechanical energy?
  22. Energy due to motion and position of an object – machine movement
  23. What is nuclear energy?
  24. Splitting apart the nucleus of an atom into smaller nuclei
  25. What is conduction?
  26. Thermal energy/Heat transfer between two objects that are touching
  27. What is convection?
  28. Thermal energy/Heat transfer through liquids or gases – warm goes up and cold goes down
  29. What is radiation?
  30. Thermal energy/Heat transfer as waves through a vacuum or empty space

Life Science:

CELLS:

  1. What is the smallest unit of all living things?
  2. cells
  3. Are all cells exactly alike? Explain.
  4. No. Cells are specialized to perform certain functions.
  5. Understand cells make up tissues – Tissues make up organs – Organs make up organ systems
  6. Cells  Tissues  Organs  Organ Systems
  7. What is the purpose of the respiratory system? What organs are involved?
  8. Respiration – breathing
  9. Lungs, trachea, mouth, nose
  10. What is the purpose of the circulatory system? What organs are involved?
  11. Transport oxygen and nutrients to the body
  12. Heart, lungs, arteries, veins
  13. What is the purpose of the digestive system? What organs are involved?
  14. Digest food
  15. Mouth, tongue, esophagus, stomach, small intestine, large intestine
  16. What is the purpose of the nervous system? What organs are involved?
  17. Communicate messages to and from the brain and body
  18. Nerves, neurons
  19. What is the purpose of the skin?
  20. Protection
  21. What is the purpose of the excretory (urinary) system? What organs are involved?
  22. Expel waste
  23. Kidneys, bladder, urethra
  24. Why do cells divide?
  25. Growth and repair
  26. What organelles do plant cells have that animal cells do not?
  27. Chloroplasts, cell-wall and central vacuole
  28. What is photosynthesis? What is necessary for it to take place?
  29. How plants make food – use light energy to make chemical energy
  30. Carbon dioxide + Water + Light energy from sun  Food (sugar) + Oxygen

INTERDEPENDENCE OF LIFE:

  1. What are the two types of factors involved in an ecosystem?
  2. Living and non-living
  3. What is a community?
  4. All of the populations in a given area
  5. What is a population?
  6. All of the members of one species in a given area
  7. What is a predator/prey relationship?
  8. One organism hunts and eats the other
  9. What is a parasite/host relationship?
  10. Parasite lives off the host harming it and possibly causing death
  11. What is a producer?
  12. Organism that makes its own food (plants)
  13. What is a consumer?
  14. Organism that eats another organism to survive
  15. What is a decomposer?
  16. Organism that breaks down the remains of other dead organisms
  17. Understand how a food web works.
  18. Producer  Primary Consumer  Secondary Consumer  Decomposers (after death)
  19. Example: Clover  Mouse  Snake  Eagle
  20. How does the Law of Conservation of Matter (Mass) apply to a fed web?
  21. The energy is not lost nor gained, simply transferred between organisms
  22. What are some factors that limit the number of organisms in an ecosystem?
  23. Competition for resources such as food, shelter, and mates
  24. What is a habitat?
  25. Place an organism lives
  26. What are some organisms that live in a temperate (Minnesota) forest?
  27. Deer, bear, squirrel, pine tree, oak tree, spiders, owl, mouse, elk, etc….

HEREDITY:

  1. What is a gene?
  2. Carriers of genetic traits – found on chromosomes
  3. What is a trait?
  4. Characteristic passed on from parent to offspring
  5. What is meant by sexual reproduction?
  6. Both male and female organism required for reproduction
  7. What is meant by asexual reproduction?
  8. Only one organism required for reproduction
  9. What is the difference between inherited and environmental characteristics?
  10. Inherited characteristics come from your parents
  11. Environmental characteristics are because of your surroundings or situation
  12. Why is the fossil record an important piece of evolutionary history?
  13. Shows examples of organisms that lived during various times and shows how organisms have changed over time
  14. Record of extinction
  15. What is Darwin’s Theory of Evolution?
  16. All species originated from one common ancestor
  17. Species have changed over time to allow for better survival
  18. What is meant by adaptation?
  19. Change in a characteristic of a species over time to ensure survival
  20. What is meant by extinction?
  21. When no more organisms of a species exist
  22. What are some environmental factors that can effect evolution?
  23. Loss of food sources, changes in climate and isolations of populations
  24. What is meant by variation?
  25. Slight differences in species that may or may not enhance survival rates

HUMAN INTERACTION:

  1. How can humans affect living organisms and ecosystems?
  2. Destruction of habitat, pollution, over-hunting, etc…
  3. What is a virus?
  4. Infectious agent that replicates inside cells
  5. What are bacteria?
  6. Single-celled microorganisms – often cause diseases
  7. What is a vaccine?
  8. Substances that build immunity to a disease without causing the disease itself
  9. What is the purpose of the immune system?
  10. Protect against microorganisms and foreign substances that may enter the body.
  11. What is the difference between renewable and non-renewable resources?
  12. Renewable = we can make more
  13. Non-renewable = once it is gone, it is gone, no more available

Earth and Space Science:

EARTH STRUCTURE:

  1. What is the Theory of Plate Tectonics?
  2. The earth’s lithosphere is made up of “plates” that float on top of the partially molten layer (asthenosphere) under it. Movement is caused by the convection currents within the magma.
  3. How do earthquakes, volcanoes, sea-floor spreading and mountain building support plate tectonics?
  4. The seven major and many minor plates move in relation to each other at one of three types of boundaries
  5. Convergent – plates push together – trenches, earthquakes, volcanoes, subduction zones, mountains, plateaus
  6. Divergent – plates pull apart – sea-floor spreading, underwater mountain chains, rift valleys, volcanoes
  7. Transform – plates slide past each other - earthquakes
  8. Describe the processes and interactions of the rock cycle.

  1. How are sedimentary rocks formed?
  2. Weathering, erosion, deposition, compaction, cementation
  3. How are igneous rocks formed?
  4. Melting and crystallization
  5. How are metamorphic rocks formed?
  6. Heat and pressure
  7. What is meant by constructive forces?
  8. Processes that build up Earth – deposition, volcanic eruptions, lava flows, mountain building, etc.
  9. What is meant by destructive forces?
  10. Processes that tear down Earth – volcanic eruptions, mudslides, landslides, erosion, etc.
  11. How have constructive and destructive forces changed the landscape of Minnesota?
  12. Volcanic rock along the North Shore
  13. Glaciers covering most of the land at one time
  14. Weathering and erosion over time
  15. What is meant by relative age?
  16. Determining the approximate age of a rock layer compared the layers/fossils around it
  17. What is meant by absolute age?
  18. Determining the exact age of a rock layer by the use of index fossils and carbon dating
  19. What does the Law of Superposition state?
  20. Oldest sedimentary rocks are on the bottom, the youngest are on the top
  21. What are index fossils?
  22. Fossil of an organism that lived in a widespread area but for a relatively short period of time
  23. What cross cutting tell you about the age of an intrusion, extrusion or fault?
  24. A extrusion, intrusion or fault is younger than any rock layer it goes through
  25. What properties are used to identify minerals? Explain.
  26. Color- surface color of a mineral
  27. Luster – way a surface reflects light – metallic, non-metallic
  28. Hardness – minerals resistance to being scratched – Moh’s hardness scale
  29. Streak – color of the mineral in powdered form – marks on a streak plate
  30. Cleavage/Fracture – how a mineral breaks
  31. Density – mass per volume (heaviness)
  32. What properties are used to classify rocks? Explain.
  33. Texture – crystal size
  34. Composition – minerals the rock is made up of
  35. What can the crystals of an igneous rock tell you about how/where it was formed?
  36. Large crystals – intrusive, formed under surface from magma, slow cooling
  37. Small crystals – extrusive, formed on surface from lava, fast cooling

EARTH’S SYSTEMS:

  1. What is the principal source of energy of the Earth?
  2. Sun
  3. What is radiation?
  4. Thermal energy/Heat transfer as waves through a vacuum or empty space
  5. What is conduction?
  6. Thermal energy/Heat transfer through direct contact/touching
  7. What is convection?
  8. Thermal energy/Heat transfer through liquids or gases – warm goes up and cold goes down
  9. How do radiation, conduction and convection work together to heat the atmosphere?

  1. Why do we have seasons on Earth?
  2. Earth is tilted – Always towards the North Star
  3. Earth revolves around the sun
  4. When is it summer in the Northern hemisphere?
  5. When Earth is tilted towards the sun
  1. What and when are the solstices?
  2. Summer Solstice – longest day of the year – June 21st
  3. Winter Solstice – shortest day of the year – December 21st
  4. What and when are the equinoxes?
  5. Two days during the year when everyone has about 12 hours of day and 12 hours of night – March 21st and September 21st
  6. What forces create currents in the oceans?
  7. Convection currents (temperature), wind, and salinity (salt concentration)
  8. What forces create currents (winds) and layers in the atmosphere?
  9. Unequal heating of the earth by the sun
  10. Rotation of the earth
  11. What is the Coriolis Effect?
  12. Winds appear to curve due to the rotation of the earth
  13. What is the jet stream?
  14. Area of fast moving air going west to east
  15. Explain the three main processes in the water cycle.

  1. What does a barometer measure?
  2. Air pressure
  3. What kind of weather does high pressure bring?
  4. Clear skies
  5. What kind of weather does low pressure bring?
  6. Clouds and precipitation
  7. What is meant by relative humidity?
  8. The amount of water vapor in the air compared to the amount the air can hold at the current temperature
  9. What is the dew point? What does it indicate?
  10. Temperature at which the relative humidity would be 100%
  11. Precipitation is highly possible
  12. In regards to temperature and pressure, which direction will winds move?
  13. Wind moves form areas of high pressure to areas of low pressure
  14. What is a sea breeze?
  15. Daytime – warmer air over the land rises and is replaced by cooler air from the sea
  16. What is a land breeze?
  17. Night – Warmer are over the water rises and is replaced by cooler air over the land
  18. What is an air mass?
  19. Large area of air that is uniform in weather conditions through out
  20. What is a cold front?
  21. Colder air moving in and overtaking warmer air
  22. What is a warm front?
  23. Warmer air moving in and over taking cooler air
  24. What are the layers of the atmosphere and key points about them?
  25. Troposphere – bottom, where the weather occurs, where we live
  26. Stratosphere – where the ozone layer is
  27. Mesosphere – where meteoroid burn up
  28. Thermosphere – where temperature increases due to ionic activity
  29. What is the composition of the atmosphere?
  30. Mostly nitrogen
  31. Also includes oxygen, water vapor, carbon dioxide, ozone, Noble gases
  32. What happens to air pressure and density as you go up through the atmosphere?
  33. They both decrease
  34. What is the role of the ozone layer?
  35. Protects Earth from the ultraviolet rays of the sun
  36. What is meant by the greenhouse effect?
  37. Trapping of certain gasses (carbon dioxide, methane) which then do not allow heat to escape the atmosphere – causes average global temperatures to increase
  38. What evidence is there of climate change in Minnesota?
  39. Evidence of melting of the glaciers leaving behind lakes, valleys and rock layering
  40. Fossil evidence of aquatic species indicating previous existence of shallow seas

EARTH IN THE SOLAR SYSTEM: