Prentice Hall Physical Science, 2006

Prentice Hall Physical Science, 2006 Chapter 1 Science Skills

1.1 What is Science A. Science from Curiosity  Curiosity is the basis of science  Science begins with curiosity and ends with discovery

B. Science and Technology  Technology is the use of knowledge to solve problems  Science and technology are interdependent

C. Branches of Science  There are three branches of natural science: physical, Earth and Space, and life - Physical science is chemistry (the study of the composition, structure, properties, and reactions of matter) and physics (the study of matter and energy and how they interact through motion and forces) - Earth and space science is geology (the study of the origin, history, and structure of Earth) and astronomy (the study of the universe) - Life science is biology (the study of the chemistry and physics of living things, the origin and the behavior of living things)

D. The Big Ideas of Physical Science  Space and Time – the universe is old and big  Matter and change - Only a small amount of the universe is matter which has volume and mass - Matter is made of atoms which are made of protons, neutrons, and electrons  Forces and Motion - Forces cause a change in motion - The laws of science govern these forces and motions  Energy - Energy exists in many forms but can transfer from one form to another - Moving objects have kinetic energy - Stored up energy is potential energy - Energy can be transferred from one form to another and from one object to another - Matter can be changed into energy - When matter changes form, energy is absorbed or released Prentice Hall Physical Science, 2006 Chapter 1 Science Skills

1.2 Using a Scientific Approach A. Scientific Methods – an organized plan for gathering, organizing, and communicating information to solve a problem or better understand an observed event  State the problem – observation leads you recognize a scientific problem  Gathering Information – use observations to find out important information about the problem and use references to get information that cannot be observed  Forming a hypothesis - An educated guess that is the proposed answer to your question - It is written in statement form  Testing the Hypothesis/Performing an Experiment - Every experiment has two variables: the independent/manipulated variable and the dependent/responding variable . Independent/manipulated variable is the thing you change that causes a change in another . Dependent/responding variable is what changes because of the independent variable - Every experiment also has parts or set-ups: the control set up and the experimental set up . experimental set-up includes the independent variable . control set-up is EXACTLY like the experimental set up, but it does NOT contain the independent variable.  Recording and analyzing data - The observations and measurements observed during the experiment are the data  Drawing Conclusions - Use the data to determine if the hypothesis is correct or incorrect  Repeat the work - Do the experiment again and again to be sure you get the same results  Developing a Theory - Once a hypothesis has been tested repeatedly a theory can be developed - A well tested explanation for a set of experimental results or observations

B. Scientific Laws  A scientific law is a statement that summarizes a pattern found in nature  It DOES NOT explain the pattern, it just states the pattern. A Theory explains the pattern.

C. Scientific Models  a model is a representation of an object or event. It can be bigger or smaller than what it represents and it can change when new information is learned about its subject  they are used to make it easier to understand things that might be too difficult to observe directly

Chapter 1 Science Skills Prentice Hall Physical Science, 2006

1.3 Measurement A. Using Scientific Notation  Scientific notation makes very large or very small numbers easier to work with  It is the value of the product of a number between 1 and 10 and a power of 10 - Examples: 1. 357, 987 = 3.57987*105 2. 0.0008706 = 8.706*10-4 3. 6.02*108 = 602,000,000 4. 6.023*1023/8.45*1021 = 71.2 or 7.12*101  Do the problems in Math Practice on p. 15

B. SI Units of Measurement  there is a standard of measurement so that everyone who measures will be able to communicate that measurement accurately that system is called SI system of the International System of Units  Base Units and Derived Units - The base units are . Length (the distance between two points) – meter (m) . Mass (the amount of matter in an object) – kilogram (kg) [gram] . Temperature (the amount of kinetic energy in an object) – kelvin (K) [Celsius] . Time - second (s) - The derived (calculated) units are . area (length *width) – square meter (m2) . volume (length*width*height) – cubic meter (m3) [liter] . density (mass/volume) – kilograms/cubic meter (kg/m3) [g/cm3 or g/mL] o density examples: 1. What is the density of an object with a mass of 15 g and a volume of 3 mL? Unknown: density Known: mass = 15 g Volume = 3 mL D=m/V D=15g/3mL D=5g/mL 2. What is the mass of an object with a density of 2 g/mL and a volume of 7 mL? Unknown: mass Known: D = 2 g/mL V = 7 mL D=m/V so m=D*V m=2g/mL*7mL m=14g  Metric Prefixes - Tells how many times a unit should be multiplied or divided by ten - Used to make the base unit more convenient (for example: you would not want to measure the distance to Huntsville in meters – you want something bigger) - The SI prefixes are . giga (G) – multiply by 1,000,000,000 (one billion or 109) . mega (M) – multiply by 1,000,000 (one million or 106) . kilo (k) – multiply by 1,000 (one thousand or 103) . deci (d) – multiply by 0.1 (one tenth or 10-1) . centi (c) – multiply by 0.01 (one hundredth or 10-2) . milli (m) – multiply by 0.001 (one thousandth or 10-3) Prentice Hall Physical Science, 2006 . micro (µ) – multiply by 0.000001 (one millionth or 10-6) . nano (n) – multiply by 0.000000001 (one billionth or 10-9) . Another way to look at it is  1 Gm = 1,000,000,000 m  1Mm = 1,000,000 m  1km = 1000 m  1 m = 10 dm  1m = 100 cm  1 m = 1000 mm  1 m = 1,000,000 µm  1m = 1,000,000,000 nm  Limits of Measurement - Precision – how exact a measurement is (how close the measurement are to one another) - Accuracy – how close a measurement is to the actual value of what is being measured - See your book p. 19 for a good example  Measuring Temperature - A thermometer is used to measure temperature - We usually measure in oC (degrees Celsius) even though the SI unit is Kelvin (K) - K = oC + 273 - oC = 5/9 (oF – 32.0o) - oF = 9/5 (oC + 32.0o)  Dimensional Anaylsis – changing from one unit to another using a conversion factor - A conversion factor is a ratio of measurements that are equal to one another . Ex: 1 dozen eggs = 12 eggs It can be written as two possible fractions: 1 dozen eggs/12 eggs OR 12 eggs/1 dozen eggs - The steps for doing conversions dimensional analysis are 1. Write down what you are given. (known) 2. Write down what you want to find. (unknown) 3. Write down your conversion factor. (it helps you get from #1 to #2) 4. Do the math. (To do the math rewrite the known, [#1] then *, then your conversion factor fraction with your known unit on the bottom and your unknown unit on the top. Next, divide the known number by what in the bottom and multiply by what in the top.) - Ex 1: Convert 47.8 m to km Known: 47.8 m Unknown: #km c.f.: 1 km = 1000 m 47.8 m *1 km/1000m = 0.0478 km

- Ex 2: Convert 0.25 pounds to grams Known: 0.25 lbs. Unknown: #g c.f.: 1 lb = 453.59 g 0.25 lb * 453.59 g/1 lb = 113.40 g

- Ex 3: How many minutes are in 4.8 hours? K: 4.8 hours Unk: #minutes Prentice Hall Physical Science, 2006 c.f.: 1 hr = 60 min 4.8 hours * 60 min/1 hr = 288 min

- Ex 4: How many seconds are in 2.75 years? K: 2.75 yr Unk: #seconds c.f.: 1 yr = 365 days 1 day = 24 hours 1 hr = 60 min 1 min = 60 sec 2.75 yrs * 365 days/1yr * 24 hr/1 day * 60 min/1 hr * 60 sec/1 min = 86,724,000 sec.

- Do the following one your own 1. Convert 18 km to miles if 1 mile = 1.61.km. 2. Convert 2 liters to quarts if 1 liter = 1.057 qt 3. How many days are in 0.36 years? 4. How many years are 31,536,000 seconds?

Chapter 1 Science Skills

1.4 Presenting Scientific Data Prentice Hall Physical Science, 2006 A. Organizing Data  Data is organized by using tables and graphs.  Data Tables – the simplest way to organize (fig. 20, p. 22)  Line graphs – useful for showing changes that occur (fig. 21, p. 23) - The manipulated (independent) variable is on the x-axis - The responding (dependent) variable is on the y-axis  Bar Graphs – used to compare a set of measurements, amounts or changes. (fig. 23, p. 24)  Circle graphs – shows how a whole is broken into its parts (fig. 24, p. 24) B. Communicating Data  Results of investigations must be reported  Information can be exchanged in conversations, emails, websites, scientific journals, or conferences