Observations, Inferences, Data, and Measurement! PROLOUGE IN EARTH SCIENCE (CHAPTER 1) PART I: The Nature of Scientific Investigations Observations, Inferences, Data, and Measurement!

Observation vs. Inference Observation: Information directly received by your 5 senses. Measurements are also observations, but are taken with instruments Rulers (for length), Scales (for mass), watch (for time), etc. Inference- to draw a conclusion or make a prediction based on your observation Q: Can someone come up with an example in this classroom right now?

Classification: The grouping of events and objects into a logical manor Ex: banana, pepper, orange, grapes, lettuce, apple, carrot Classify these items above. In class Practice: Inference vs. Observations Worksheet

PART II: Measurement Measurements include: 1.)Mass- the amount of matter in an object -use with a scale in grams or kilograms 2.) Length- the distance between 2 points -use rulers & meter sticks for mm, cm & m. 3.) Volume- How much space something occupies. - Use graduated cylinder or beaker (fluids) -ruler using the L x W x H formula

Length

Length from small to big move left! from big to small move right! We will generally be using metric in this class 1000.0 mm= 100.0 cm = 1.0 m To convert from: 1.)m cm, move decimal place 2 spaces to right 2.)cmm, move decimal 2 spaces to left 3.) mmcm, move decimal 1 space to left 4.) cm mm, move decimal 1 space to right 5.) mm m, move 3 spaces to left

Let’s try some together First determine if you’re going “left or right” Kilo I Hecto I Deca I Unit I deci I centi I milli 5 (m)= ______ (cm) 5(m)=________(km) 50(cm)=_____(m) 50(cm)=_____(mm) 3 (km)= ______(m) 300(mm)=_____(km)

Measuring and converting Mass 1.0 kilogram (kg) = 1000.0 grams (g) To convert g kg move decimal place 3 spaces to left To convert kgg move decimal place 3 spaces to right!

Volume units: cm³ (solids) , or mL (fluids) 1.) L x W x H= Volume of a solid 2.) Fluid (mL) using graduated cylinder *1 cm³ = 1ml ³

Finding Volume of an Irregularly Shaped Solid or Sphere 1.) Fill graduated cylinder up to known value and record “original volume” 2.) Add object 3.) Record “New Volume” 4.) V new – V original= V of solid!

Complete Measurement Activity and Measurement MC questions Activities Complete Measurement Activity and Measurement MC questions

A simple experiment using Observations and Inferences

Step 1: Observe and Infer so that you may experiment! a.) Observation: The egg is floating in the water Question for experiment:why is the egg floating in one of the containers? b.) What’s your inference about why this egg is floating? 1.) 2.) 3.)

Step 2: Test A good experiment will only test ONE variable (SOMETHING THAT CHANGES THE OUTCOME) Possible Variables: Size of the Egg? Temperature of the Water? Cooked or Raw? What’s IN the water…? Determine how variables will be controlled & measured in your experiment: Independent Variable: The one manipulated (changed) Dependent Variable: Factor that CHANGES due to change in the independent Control: Variable(s) that do NOT Change; used to show that the result of experiment are the result of what’s being tested

Step 3: Analyze 1.) Organize data: graphs, tables, charts 2.)Look for Trends: (the more salt added to the water the more the egg floats) 3.)Compare data with actual hypothesis/inference

Analyzing Data Graphically Independent variable causes a change in Dependent Variable! Ie: Salinity of water causes a change in density (which we see by the flotation of the egg) . It isn’t possible that density could cause a change in salinity. Dependent Y axis Independent = X-axis

Step 4: Conclude 1.) What’s your conclusion after looking at the data? The more (g) of salt added, the higher density of the water (so the more the egg floats)

PART III: Density, Physical Changes and Phase Changes In order to solve for Density, what must we know about an object or liquid? Formula for Density= Mass Volume

Formula for Density M=DV and V= M/D D = M/V which means units are g/ml (liquid) or g/cm³ (solid) You can also solve for Mass or Volume if given Density: M=DV and V= M/D

Determining Density 1.) Mass= quantity of matter (kg), (g) , (mg) using a scale or balance 2.) Volume= amount of space it occupies (L), (mL) or (cm³), using a graduated cylinder or ruler Volume (V)=LxWxH or measure fluid displacement

Which bar of gold is the most dense? Rule: No matter how much (or how little) of a substance you have, the density stays the same Exception: The matter goes through a phase change…we will talk about this soon 6000 (g) of gold 1000 (g) of gold Gold=19.3 g/cm3 Which bar of gold is the most dense? 21

Sample Problems: 1.)The Density of an object has a mass of 20(g) and a volume of 10 (mL), what is the Density? 2.)A box which measures 2 (cm) high, 5 (cm) wide and 12 (cm) long has a mass of 30(g). What is the density? 1.) 2 g/ml 2) V= 120 cm3 so D = 30/120 = 0.25 g/cm3

When does Density Change? 1.)If there is a change in Temperature As T ↑ a substace will expand making the volume larger and thus, density less (↓) Also phase changes: slg 2.) If there is a change in Pressure -As P ↑ a substance compresses, thus the volume↓ making the density higher ↑ - As P ↓, volume ↑ which means density ↓

Temperature: With Increased temperature going from the ice to the flame, the air molecules inside the balloon expand, thus increasing in volume and decreasing the density of the air in the balloon Pressure: With Increased pressure from pushing the cork downwards, the air molecules inside the vessel contract, thus decreasing in volume and increasing the density of the air in the vessel

Phase changes and Density The density of a substance always stays the same UNLESS it goes through a phase change (GasLiquidSolid) OR we change other environmental conditions such as temperature and pressure

How density CAN change: 1.) Pressure: With increased pressure, the density of a substance increases ( Conversely if P ↓, D ↓ ) 2.) Temperature: With increased temperature, the density of a substance decreases (Conversely if T ↓ = D ↑ )

Ex: A peanut butter and jelly sandwich gets completely squished in your backpack. Has the density changed? What about the regular sandwich if you decided to share and cut it in half…Did your half change in density?

Is liquid or solid gold more dense?

Which is more dense? Steam or liquid water?

Density of H20 Water, unlike other substances, is MOST dense in its liquid form . How do you know this already? At about 4 ̊C, d=1.0g/cm³ Objects that are LESS dense than water will float Objects that are MORE dense will sink Objects that stay suspended are roughly the same

Determining Relative Density Question: If you dropped 4 different objects all with different densities into a tub of water, how would they arrange themselves? Draw a sketch in your notes right now: Circle: 0.5 g/cm³ Triangle: 0.8 g/cm³ Star: 1.0 g/cm³ Diamond: 2.0 g/cm³

Explanation

Brain Teaser: Steel has a density of 7.85 g/cm3 So why do ships float?

Where is the magnetite going to come to rest?

Density on a graph Liquid A is DENSER than liquid B. On a graph, the item with the steepest slope (greatest ratio of mass to volume) will be the most dense and vice-versa

Density on graphs: Practice Problems 1.) Find the Density of Liquid A 2.) What is the mass of 18 ml of liquid b? What is the density? What substance must this be? 3.) Which liquid is the least dense?

Layers of the Earth pg. 10 in ESRT Extension Q:How and why did the earth come to be separated into layers?

Scientific Notation (using exponents) M x 10 ^n M is a # between 1-10 1.) Whole numbers: move to the left 2,5002500  2.5 x 10³ 900,000900000 9 x 10 5 2.) Decimals: move to the right and use (-) .0081 .00818.1 x 10-³ .0518 .0518 5.1 x10-²