7th Grade Science Midterm Review

1. 7th Grade ScienceMidterm Review

2. What is science? • Science is the study of the natural world. • Science is divided up into three areas: • Biology/Life science • Geology/Earth science • Physics/Physical science

3. What is empirical evidence? • The observations, measurements, and other types of data that people gather and test to support and evaluate scientific explanations.

4. What is a theory? • The explanation for some phenomenon that is based on observation, experimentation, and reasoning; that is supported by a large quantity of evidence; and that does not conflict with any existing experimental results or observations.

5. What is a law? • A descriptive statement or equation that reliably predicts events under certain conditions.

6. What is the difference between a theory and a law? • Theory is an explanation for why something is the way it is and law describes what is happening in the natural world.

7. Where do scientists get their evidence? • In the field • In the laboratory

8. How do scientific ideas change? • By new evidence • By collaboration and debate

9. What is an experiment? • An organized procedure to study something under controlled conditions.

10. What is an observation? • The process of obtaining information by using the senses; the information obtained by using the senses.

11. What is a hypothesis? • A testable idea or explanation that leads to scientific investigation

12. What is an independent variable? • The factor that is changed by the experimenter

13. What is a dependent variable? • The factor that changes as a result of manipulation of one or more independent variables.

14. What is data? • Information gathered by observation or experimentation that can be used in calculation or reasoning

15. What are the steps of the scientific method? (Please refer to your notes and foldable) 1. Make an observation 2. Ask a question 3. Hypothesis 4. Experimentation / collect data 5. Results (typically represented in data tables, graphs, mean, median, etc in middle and high school) 6. Analyze / conclude 7. Repeat

16. What is repetition? What is replication? What is the difference between them? • Repetition is when a scientist repeats their own experiment • Replication is when a scientist repeats different scientists experiment

17. What characterizes a good scientific investigation? It needs to be able to be repeated

18. How do you evaluate the quality of scientific information? • The most reliable scientific information is published in peer-reviewed scientific journals. (The information has to be peer-reviewed.)

19. What is a model? • A pattern, plan, representation, or description designed to show the structure or workings of an object, system, or concept

20. How do scientists organize data? • Scientists organize data in tables and then in charts, models, and graphs.

21. What are the different types of graphs and why do we use them? • Circle Graph- shows how each group of data relates to all of the data • Bar Graph- Used to display and compare data in a number of categories • Line Graph- Used to show change in variables over time

22. Unit 2: Study Guide

23. What is a mineral? How are minerals formed? • A mineral is a naturally occurring usually inorganic solid that has a definite crystalline structure and chemical composition. • Minerals are formed: • As magma and lava cool • By metamorphism • From solutions

24. What is an element? • Elements are pure substances that cannot be broken down into simpler substances by ordinary chemical means

25. What is a compound? • A substance made up of atoms or ions of two or more different elements joined by chemical bonds.

26. What is the difference between silicate and nonsilicate minerals? • Silicate minerals contain silicon and oxygen, normally in the form of silicate tetrahedrons. • Nonsilicate minerals do not.

27. What are the different properties that can be used to identify minerals? Define each property. • Color- color of the mineral • Streak- color of the powdered form of the mineral. (Remember: that if a scientist draws on a white tile with the mineral, this is how the streak is found.) • Luster- way a surface reflects light • Cleavage and Fracture- The way the mineral breaks/splits • Density- measure of how much matter in a given amount of space. • Hardness- mineral’s resistance to being scratched. • Special Properties- any property specific to the mineral

28. Know the three different rock types: What are they? How are they each created? • Igneous rock forms when magma or lava cools and hardens • Sedimentary rock forms from compressed or cemented layers of sediment. • Metamorphic rock forms from other rocks as a result of intense heat, pressure, or chemical processes.

29. What is weathering? • Weathering is the natural process by which atmospheric and environmental agents, such as wind, rain, and temperature changes, disintegrate and decompose rocks.

30. What is erosion? • Erosion is the process by which wind, water, ice, or gravity moves soil and sediment from one location to another.

31. What is deposition? • Deposition is the process in which material is laid down.

32. What is the rock cycle? • The rock cycle is the series of processes in which rock forms, changes from one type to another, is destroyed, and forms again by geologic processes. • Look in your book on page 78 for a diagram of the rock cycle.

33. What is uplift? • Uplift is the rising of regions of Earth’s crust to higher elevations.

34. What is subsidence? • Subsidence is the sinking of regions of the Earth’s crust to lower elevations.

35. What is a rift zone? • A rift zone is an area of deep cracks that forms between two tectonic plates that are pulling away from each other.

36. What are Earth’s compositional layers?(Make sure you can label them) Crust Mantle Core

37. What is convection? Where does convection take place in Earth and why is it important? • Convection is the movement of matter due to differences in density that are caused by temperature variations; can result in a transfer of energy as heat. • Convection takes place in the Earth’s mantle. • Convection helps rocks move slowing in the mantle. (Cooler rocks sink and warmer rocks rise)

38. What are the Earth’s physical layers?(Make sure you can label them) Lithosphere Asthenosphere Mesosphere Outer Core Inner Core

39. What is Pangaea? Why is the idea of Pangaea important in understanding Earth’s history? • Scientists think that about 245 million years ago the continents were joined in a single large landmass that they call Pangaea. • It’s important to understand that at one time scientists think that all the continents were connected and during millions of years the continents moved into their current locations.

40. What is sea-floor spreading? • Sea-floor spreading is the process by which new oceanic lithosphere sea floor forms when magma rises to Earth’s surface at mid-ocean ridges and solidifies, as older existing sea floor moves away from the ridge. • Older rock- far from ridge • Newer rock- formed near ridge

41. Theory of plate tectonics • This theory explains how large pieces of the lithosphere, called plates, move and change shape.

42. What is a tectonic plate? • A tectonic plate is a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle.

43. Different plate boundaries(Know the arrow diagrams!) • Convergent- Two plates collide. • Divergent- Two plates move away from each other • Transform- Two plates move past each other horizontally

44. What are the three different mechanisms that cause tectonic plates to move? • Mantle Convection • Ridge Push • Slab Pull

45. What is an anticline?(Look on Page 107 for a diagram) • Anticlines- oldest layers of rock are in the middle of the fold. The youngest rocks are towards the outside. Anticlines are shaped like a: n

46. What is a syncline?(Look on Page 107 for a diagram) • In syncline folds the youngest rocks are in the middle and the older rocks are on the outside edges. Synclines are shaped like a: u

47. Faults • Strike-Slip Faults • Formed when rocks are under shear stress and at transform boundaries • Normal Faults • Formed when rocks undergo tension and at divergent boundaries • Reverse Faults • Formed when rocks undergo compression and at convergent boundaries

48. Faults • Be able to label a diagram of each fault, with where the hanging wall, footwall and fault plane are! (Look on page 109)

49. Three types of mountains • Folded Mountains- Form when rock layers are squeezed together and pushed upward. • Usually at convergent boundaries • Volcanic Mountains- Form when melted rock erupts onto Earth’s surface • Fault-Block Mountains- Form when tension makes the lithosphere break into many normal faults. Along the faults, pieces of the lithosphere drop down compared with other pieces. The pieces left standing form fault-block mountains.

50. What is an earthquake? • Earthquakes are ground movements that occur when blocks of rock in Earth move suddenly and release energy. • Label #6 page 116 in your book. • Know that the Focus is the point underneath the Earth • The Fault Line is the line between both of the plates • The Epicenter is on the Earth’s surface.