INTRO TO SCIENCE. Chapter 1. 8 th grade

Transcription

1 INTRO TO SCIENCE Chapter 1 8 th grade

2 1.1- INTRODUCTION TO SCIENCE Science- the study of the matter and movement of God s physical creation. Matter- the substances of the physical world- anything that has mass and takes up space. Law of Conservation of Mass- matter cannot be created or destroyed- only change forms. Pedology- the study of soil.

3 THE SCIENTIFIC METHOD Scientific Method- an organized way for scientists to gather and pursue scientific knowledge. State the problem. Gather information related to your problem. Form a hypothesis- an if.then statement- what you expect will happen in the experiment based on your previous knowledge and research. A hypothesis must be testable, and must also be falsifiable- meaning it can be proven false. Design an experiment to test your hypothesis. Make observations and record data. Analyze data and draw conclusions.

4 THEORY VS. LAW Theory- a way of EXPLAINING an event based on a set of facts. Theories must be able to predict future events. Law- a unifying statement based on numerous observations Laws sometimes include a mathematical equation.

5 LAW OR THEORY- WHITEBOARDS An object at rest will remain at rest unless acted on by an outside force. An object in motion will remain in motion unless acted upon by an outside force. The earth rests on large plates that shift and cause movement and changes in geographic structure. The volume of a definite quantity of gas is found by the formula P 1 V 1 =P 2 V 2. Organisms change over time as they adapt to their environment. This produces small changes in DNA and can result in new variations of a species. Thermal energy always moves from a greater energy level to a lesser level.

6 EXPERIMENTAL DESIGN Experimental Variables- factors that an experimenter can control. Independent Variable- the variable that you change to test your hypothesis. Dependent Variable- the variable that is measured to determine the results of the experiment. Controlled Variables- all other factors that should be kept the same between the experimental and control groups. (ex: temperature, sunlight, amount of water, etc).

7 EXPERIMENTAL DESIGN Experimental Groups- the groups on which the experiment is performed. Control Group- a group where the independent variable is absent. This group is not tested but used as a standard for comparison. Not every experiment will have a control group. If a control group is not used, 2 or more experimental groups must be compared together.

8 BELLRINGER- ENGINEERING DESIGN- PAGE 5 What does the term criteria mean in relationship to an experiment? What are constraints? Why is it important to conduct research about your problem before you begin experimentation? What is a prototype? In step 6, Jasmine had to alter her design and repeat her experiment. Why is this sometimes necessary in science? Aside from waterproofing, what could be another problem that Jasmine could address in improving her oven design?

9 1.2- SCIENTIFIC REASONING Logic- the study of reasoning. Deductive Reasoning- uses general evidence to make a specific inference. Example: Thunder is always caused by lightening in thunderstorms. Deductive reasoning would tell us that if you hear thunder, there is lightening nearby, even if you do not see it. Inference- a conclusion based on reasoning from evidence.

10 DEDUCTIVE REASONING Proposition- a statement of fact in deductive reasoning. Hypothetical Proposition- a special type of proposition that has two parts- a condition if and the conclusion then. The condition ( if ) is sometimes referred to as the antecedent, and the conclusion ( then ) as the consequent. Example All fish have gills. (proposition) If an animal has gills, then it is a fish. (hypothestical proposition) Whales and dolphins do not have gills, therefore, whales and dolphins are not fish. (inference using deductive reasoning)

11 INDUCTIVE REASONING Inductive Reasoning- uses specific evidence to make a more broad conclusion and help to determine cause and effect. Utilizes the method of difference. In the method of difference, two situations are the same except for one factor. If a change occurs, we know that the factor is at least partially responsible for the change in effect. May be used to develop a hypothesis. Can never prove a hypothesis beyond all doubt.

12 A WELL DESIGNED EXPERIMENT Repeatability- if you repeat the experiment multiple times, keeping all factors as similar as possible, you will essentially get the same results. Reproducibility- others will reach the same conclusion by performing your experiment themselves under different conditions AND by performing other experiments that test the same hypothesis. Post Hoc Fallacy- when one assumes that a change in one factor caused a change in another factor, since the second change occurred after the first. A well designed experiment, with appropriate variables and controls will help to eliminate post hoc fallacy.

13 SCIENTIFIC MODELS Model- anything that provides a partial representation of something else. Physical model Verbal model Visual model Mathematical model

14 ESSENTIAL DEFINITIONS- PAGE 11 Atoms- the most basic units of matter. Molecules- groups of atoms linked together. Ex: Sucrose (table sugar) is C12H22O11. 1 molecule of sugar is made of 12 atoms of Carbon (C), 22 atoms of Hydrogen (H) and 11 atoms of Oxygen (O) Mass- the amount of matter in an object. Weight- the pull of gravity on an object. Volume- the amount of space that matter takes up. Density- how tightly packed the matter is. Density can also be defined as mass per unit volume and is often measured as grams/cm 3.

15 1.3- CHARACTERISTICS OF SOIL Organic Material- materials primarily derived from living organisms. These materials are also mixed with Mineral Materials, which are those derived from nonliving matter, such as rocks and minerals. Decomposition- the process where bacteria and fungi break down plant and animal remains, leaving behind minerals an humus in the soil. Humus- any substance composed of decayed organism remains. Humus helps to enrich the soil with nutrients. Recycling- reusing old materials Ex: composting Weathering- the process that breaks down rocks into soil.

16 SOIL HORIZONS (AKA: SOIL LAYERS) Topsoil- the upper level of soil which contains the most organic material. Subsoil- lighter in color than topsoil because it contains less organic material and more mineral material. Bedrock- provides a firm foundation for the earth s surface.

17 SOIL TEXTURES The type of rock and method of weathering determine the particle size and composition of mineral materials. The combination of different sizes and mineral particles determines the texture of the soil. Sand- coarse and gritty with large, easily seen particles. Allows air and water into the soil. Silt- smaller particles than sand, some are even microscopic. Has the texture of flour. Clay- has the smallest and most tightly packed particles. Loam- a mix of sand, silt, clay, and humus.

18 CHARACTERISTIC COLOR The color of soil depends on the amount of organic material and types of minerals present. Dark soils contain more organic materials than light soil. Munsell Chart- provides names and descriptions of soil colors.

19 PREFERRED PH Soil can be described as basic, acidic, or neutral, with ph values ranging from ph Scale- ranges from Below 7- acids Above 7- bases 7- neutral

20 1.4- SOIL NUTRIENTS Nutrients- nourishing substances provided by organic materials and minerals. The three most important nutrients for plants are Nitrogen, Phosphorous, and Potassium. Fertilizer Composition Phosphates- fertilizers containing phosphorous. Potash- fertilizers containing potassium. Nitrates- fertilizers containing nitrogen.

21 PHOSPHOROUS AND POTASSIUM Phosphorous is essential for cell division and growth. It is vital for photosynthesis and promotes plant maturation. Potassium s primary function is to contribute to the general health of the plant and improve disease resistance. It encourages root growth and fruit formation.