Chapter 1 Science Skills Mr. Bruder

What is Science? Science is what scientists do Science is trying to explain the world around us Science is a way of thinking “Science is a system of knowledge based on facts or principles Book talks about “social science” We prefer social studies

Branches of Science Science Biological Science Earth Science Physical

Branches of Science Science Biological Science Earth Science Physical Zoology Botany Science of living things Ecology

Branches of Science Science Biological Science Earth Science Physical Physics Chemistry Science of matter and energy

Branches of Science Science Biological Science Earth Science Physical Geology Meteorology The systems of the earth Astronomy

Branches of Science There are many more branches to biological and earth sciences The three categories overlap Biochemistry Astrobiology Geophysics

What is Chemistry? The study of matter, its composition, properties, and the changes it undergoes Applied Chemistry is the using of chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing Pure Chemistry gathers knowledge for knowledge sake

Which Comes First? Applied Chemistry Pure Chemistry usually comes first, applied later Called technology Or engineering Pure chemistry can explain behavior that has been used without knowing why Steel swords Can’t be good or bad Can be good or bad depending on use

Chemistry is A natural science A language with its own vocabulary A way of thinking

Branches of Chemistry Analytical Chemistry -studies composition of substances. Organic Chemistry -compounds containing carbon Inorganic Chemistry -substances without carbon Biochemistry- Chemistry of living things Physical Chemistry studies behavior of substances rates and mechanisms of reactions energy transfers

Science From Curiosity Science begins with curiosity and often ends with discovery. How or Why is this possible? Curiosity provides questions but is seldom enough to achieve scientific results. Then how do we achieve these results?

Observations Qualitative – describe with words Hot , red, large Quantitative – describe with numbers 100° , 10 meters, 3.46 grams Scientists prefer quantitative Easy to agree upon No personal bias

Models A representation of some object or event Made to better understand it Often used if real thing is too big, small or complex. Come in a variety of forms Physical models Diagrams Computer models

The Scientific Method A way of thinking about and solving problems It is a logical method You do it all the time

Scientific Method A way of solving problems or answering questions Starts with observation- noting and recording facts Hypothesis- an educated guess as to the cause of the problem or answer to the question

Scientific Method Experiment- designed to test the hypothesis Only two possible answers 1) hypothesis is right 2) hypothesis is wrong Generates data observations from experiments Modify hypothesis- repeat the cycle

The Scientific Method Does not always work this way, but gives a way of guiding our thinking Hard part is testing only one variable at a time. Changing only one thing at a time If you change more than one, you don’t know which one is the cause

Variables Controlled experiment- Only want one thing to change at a time in a laboratory. Manipulated variable- What you change or control directly Also called independent variable Responding variable – What changes as a result. No direct control Also called dependent variable

Observations Hypothesis Experiment Cycle repeats many times. The hypothesis gets more and more certain. Becomes a theory A thoroughly tested model that explains why things behave a certain way. Observations Hypothesis Experiment

Theory can never be proven. Useful because they predict behavior Help us form mental pictures of processes (models) Observations Hypothesis Experiment

Another outcome is that certain behavior is repeated many times Scientific Law is developed Description of how things behave Law - how Theory- why Observations Hypothesis Experiment

Law Modify Observations Theory (Model) Hypothesis Experiment Prediction Modify Experiment Experiment Law

Law vs. Theory Law Theory Describes how Explains why Summarizes observations Agrees with observations Usually an equation Predicts new discoveries

Law vs. Theory Theory can’t be proved; always the possibility that a new experiment will disprove a theory Law described a natural phenomenon, but does not attempt to explain it

Measurement How do we measure in science? What do measurements mean? How do we tell? Let’s start with Accuracy vs. Precision

How good are the measurements? Scientists use two words to describe how good the measurements are- Accuracy- how close the measurement is to the actual value Precision- how well can the measurement be repeated

Differences Accuracy can be true of an individual measurement or the average of several Precision requires several measurements before anything can be said about it

Let’s use a golf anaolgy

Accurate? No Precise? Yes

Accurate? Yes Precise? Yes

Precise? No Accurate? Maybe?

Accurate? Yes Precise? We cant say!

Examples Multiple Measurements Correct Repeatable Reproducible Single Measurement True Value

Scientific Notation To write in Scientific Notation you need a number between 1 & 9 in front of the decimal. When going from right to left you add the exponent (positive exponent) When going from left to right you subtract the exponent (negative exponent)

Converting Cont. Examples 345 .000345 56890 .000000000134

The Metric System

Measuring The numbers are only half of a measurement It is 10 long 10 What????? Numbers without units are meaningless

The Metric System Easier to use because it is a decimal system Every conversion is by some power of 10 A metric unit has two parts A prefix and a base unit Prefix tells you how many times to divide or multiply by 10

Base Units Length - meter more than a yard - m Mass - grams - a bout a raisin - g Time - second - s Temperature - Kelvin or ºCelsius K or C Energy - Joules- J Volume - Liter - half f a two liter bottle- L Amount of substance - mole - mol

Prefixes kilo k 1000 times deci d 1/10 centi c 1/100 milli m 1/1000 kilometer - about 0.6 miles centimeter - less than half an inch millimeter - the width of a paper clip wire

Volume Calculated by multiplying L x W x H A liter volume of a cube 1 dm (10cm) on a side…. So 1L = 10cm x 10cm x 10cm 1L = 1000cm3 1/1000L = 1 cm3 1mL = 1cm3

Mass Weight is a force. Mass is the amount of matter. 1g is defined as the mass of 1 cm3 of water at 4 0C. 1000g = 1000 cm3 of water 1kg = 1L of water

Converting k h D d c m how far you have to move on this chart, tells you how far, and which direction to move the decimal place. The box is the base unit, meters, Liters, grams, etc.

k h D d c m Conversions 5 6 Change 5.6 m to millimeters starts at the base unit and move three to the right. move the decimal point three to the right 5 6

k h D d c m Conversions convert 25 mg to grams convert 0.45 km to mm convert 35 mL to liters It works because the math works, we are dividing or multiplying by 10 the correct number of times

Conversions k h D d c m Change 5.6 km to millimeters

Which is heavier? it depends

Density How heavy something is for its size The ratio of mass to volume for a substance D = M/V Independent of how much of it you have Gold- high density Air- low density

Calculating The formula tells you how Units will be g/ml or g/cm3 A piece of wood has a mass of 11.2g and a volume of 23mL. What is the density? A piece of wood has a density of 0.93 g/mL and a volume of 23 mL what is the mass?

Floating Lower density floats on higher density Ice is less dense than water Most wood is less dense than water Helium is less dense than air. A ship is less dense than water

Density of Water 1g of water is 1mL of water Density of water is 1 g/mL At 40C Otherwise it is less

Measuring Temperature 0ºC Celsius scale. water freezes at 0ºC water boils at 100ºC body temperature 37ºC room temperature 20 - 25ºC

Measuring Temperature 273 K Kelvin starts at absolute zero (-273 º C) degrees are the same size C = K -273 K = C + 273 Kelvin is always bigger. Kelvin can never be negative.

Temperature A measure of the average kinetic energy Different temperature scales, all are talking about the same height of mercury. Derive a equation for converting ºF toºC

Calculating Temp. From Celsius to Fahrenheit F= (C x 9/5) + 32 From Fahrenheit to Celsius C= 5/9 (F-32) Examples: 49 0F to 0C 97 0C to 0F

Converting Kelvin Converting Kelvin to Celsius K = C + 273 Converting Celsius to Kelvin C = K – 273 Why is there no conversion from Kelvin to Fahrenheit?

Problems How many???? 349K to 0C 120C to K 340F to 0C 1010C to 0F

Temperature is different from heat. Temperature is which way heat will flow. (from hot to cold) Heat is energy, ability to do work. A drop of boiling water hurts, kilogram of boiling water kills.