Introduction to Science Chapter 1

The nature of science Section 1

What is science? Science is the study of… Everything!! A way of learning about the natural world. Scientist: a person who studies, or has expert knowledge of a natural or physical science

Physical Science Physical Science: The study of matter and energy Matter: the stuff the universe is made of Energy: ability to do work Two major classes of physical science Chemistry: the study of interactions of matter Physics: the study of motion and energy

Theories & Laws Law: describes a process in nature that can be tested by repeated experiments Based on facts and have been proven, If not supported by new information, the law is rejected Law of Conservation of Energy Theory: attempts to explain why these processes and observations are so. Based on observations and can be tested, If new information if discovered, the theory is changed Theory of Evolution BOTH SUPPORTED BY EVIDENCE

Models & Technology Model: any representation of an object or a system Technology: the application of science for practical purposes We are surrounded by this daily! Cathode Rays, CT Scans

The way science works Section 2

Scientific Method Method of organizing information and solving problems Make an observation (use your 5 senses) Ask a question Research Form a hypothesis (predict an outcome) Experiment (test the hypothesis) Analyze your results (record and organize your data) Draw conclusion (was your prediction correct?) Repeat your work and share it with others

Scientific Method Observation: I can’t wake up for school Question: How can I get up on time? Research: Go to bed earlier, set alarms, less technology before bed Hypothesis: If I go to bed earlier, then I will be able to wake up. Experiment: Try to go to bed earlier, and record if you get up earlier Analyze your results: Did it work each day? Draw conclusion: Did you confirm or disprove your hypothesis? Repeat & Share: Always double check, tell someone about your discovery

Experiment Experiment: a controlled procedure carried out to test a hypothesis Variable: condition or trait you are testing (or changing) Independent variable: this variable is manipulated by the experimenter, DOES NOT change in response to other variables Dependent variable: the variable that changes in response to the independent variable, or being measured Only ONE variable is tested in an experiment!!

experiment Control group: does not receive the variable Experimental group: exposed to the independent variable, then compared to the control group NO EXPERIMENT IS A FAILURE!

data Qualitative: data that cannot be measured, it describes a quality The softness of a cat’s fur, the color of the sky Quantitative: data involving number, it shows a quantity The age of your car, the hairs on your head

Lab Safety Failure to follow lab safety rules will result in disciplinary consequences!

equipment Metric Ruler: measures distance in centimeters, each line in between represents a millimeter (one tenth of a centimeter) Graduated Cylinder: measures volume in milliliters Meniscus: lowest point of the curve, read from here by putting your head at the same level

Measurement Math is the language of science Scientists use the SI system (Systeme International d’Unites) because it is consistent The SI system is based on the metric system and has BASE UNITS of measurement

Metric system Measurements are made in specific units called BASE UNITS Length: distance Base Unit: meter (m) Volume: amount of space something takes up Base Unit: liter (L) for liquids, centimeters cubed (cm3) for solids Mass: amount of matter in an object (not the same as weight) Base Unit: gram (g) Time: the amount of time something takes Base Unit: second (s) Temperature: how hot or cold something is Base Unit: Celsius (°C) or Kelvin (K)

Metric system Some measurements are too large or small to be measured in meters, liters, or grams so we add prefixes to them in order to avoid decimals and a lot of zeroes Prefix: something added to the front of a word to change its meaning Metric prefixes represent multiples of ten Add the prefix symbol to the base unit symbol when writing a unit of measurement kilo meter k m

Metric system km = 1,000 meters

conversions Converting from one metric unit to the other Write down - G’’ M’’ k H Da base d c m Put your pencil on the given unit (km) Move the necessary number of spaces to get to the desired unit (m) In this case, 3 to the right G’’ M’’ k H Da base d c m Then move the decimal point from the original quantity the same amount 1 km = 1,000 m

conversions 387 g to kg 551 cm to m 398 ml to L 0.57 g to mg 58700 cm to km 0.387 kg 5.51 m 0.398 l 570 mg .587 km

Organizing data Section 3

Graphs Graphing is an important procedure used by scientists to display data collected during an experiment. There are three types of graphs Line, Bar, Pie Each graph contains items that help you read the graph and understand the data being shown

Graphs Line Graphs: Shows continuous change, and the relationship between two variables Bar Graph: Show a comparison between similar items or events, or representing a single value for many items Pie Graph: Show the parts of a whole, adds up to 100%

Graphs Title: tells what the graph is about. It should be a concise statement placed above the graph. Dependent variable: placed on the y-axis (vertical) Independent variable: placed on the x- axis (horizontal)

graphs Variable Scales: A scale is used so you know where to plot the points representing the data and must include all the data points. The scales should start with 0 and increase by the same amount, your data will determine these values Legend: a key to reading the data in your graph

Scientific Notation Scientific notation is used to express really BIG or SMALL numbers more easily. It is expressed as 2 factors: Factor #1: a number between 1 and 10 Factor #2: a power of ten 6.8 x 104 = 68,000 The exponent on 10 tells you the number of places to move to the decimal If the exponent is positive, you move to the right If it is negative, you move to the left

Quick conversions 6.7 x10-7 2.31 x105 5.79 x103 4.19 x10-5 .0065 94,100,000 .000000065 9,840 .00000067 231000 5790 .0000419 6.5 x10-3 9.41 x107 6.5 x10-8 9.84 x103