Topic 1: Introduction Earth Science

Observations & Inferences

Observations & Inferences The measuring or observing something using your Five Senses. Sight Smell Touch Hear Taste An interpretation (guess) based on your observations.

Practice Questions: Observation or Inference The dog’s tongue is hanging out. ___________ The dog is thirsty. _____________________ The rock is smooth, gray and contains quartz. __________ The rock formed below the earth’s surface. _________ The sky contains a lot of clouds. _______________ A storm is coming soon. __________________

Classification: The grouping of items by using similar characteristics. How would you classify the following things:

Measurements An observation that is compared to a known standard. Usually made with an instrument. Examples: Mass (grams, kilograms, pounds, ounce) Length (meter, foot, mile, kilometer) Time (minute, second, hour)

(Ask yourself, “How many zeros are in the #10?) Rounding Numbers: Unless otherwise stated, ALL measurements and calculations MUST be rounded to the nearest tenth. (Ask yourself, “How many zeros are in the #10?) 7.369cm =

Averaging Numbers: When you calculate an average, you simply _____ the numbers and then ________ by the number of digits you added. Now it’s your turn… Find the averages of the following values and round your answer to the nearest 10th. 1st Value 28.0 2.117 127.9 50.0 35.678 2nd Value 34.0 6.89 404.0 70.0 35.985 3rd Value - 543.5 60.0 35.789 Average  

Graphing Relationships & Change

Independent Variable: Variable that stands alone and is compared to. Graphs: Method of organizing and comparing data (variables) making it easy to read. Independent Variable: Variable that stands alone and is compared to. Ex) Time Dependent Variable: Variable whose changing value is measured. Ex) Mass, Volume, Temperature

Time (min) Temperature (oC) 30 1 33 2 38 3 40 4 41 5 42 6 43 7 44 8 45 30 1 33 2 38 3 40 4 41 5 42 6 43 7 44 8 45 9 10

Graphing Relationships: Direct Relationship: Where both variables are changing in the same way. Indirect Relationship: Where the two variables are changing in opposite ways. Cyclic Relationship: Where the two variables change in a reoccurring pattern.

How much that is measured (field) changes over time. Rate of Change: How much that is measured (field) changes over time. Rate of Change = --------------------------------------------- The greater the Rate of Change the Steeper the Slope of a graph. Rate of Change = Change in Field Value Change in Time

Which letter has the greatest rate of change? How do you know? Section A has the greatest RoC because it is the steepest part of the graph.

Problems: using your graph from the previous page Calculate the Rate of Change for time 0 – 5min. Calculate the Rate of Change for time 5 – 10min. Calculate the Rate of Change for time 0 – 10min. RoC = 42DC – 30DC 5min RoC = (42DC – 30DC) / (5min – 0min) = 12DC/5min = 2.4DC/min 2. RoC = 45DC – 42DC RoC = (45DC – 42DC) / (10min – 5min) = 3DC/5min = 0.6DC/min 3. RoC = 45DC – 30DC 10min RoC = (45DC – 30DC) – (10min – 0min) = 15DC/10min = 1.5DC/min

Rate of Change and Graphs Which of the following three graphs has the greatest rate of change? Explain how you know. Graph C because it has the steepest slope. The greater the Rate of Change the Steeper the Slope of a graph.

Prediction of Change: an inference about the conditions and behavior of the variables in the future. Using the graph you created on the previous page, can you predict what the temperature might be at time 15 minutes?

Time (min) Temperature (oC) 30 1 33 2 38 3 40 4 41 5 42 6 43 7 44 8 45 30 1 33 2 38 3 40 4 41 5 42 6 43 7 44 8 45 9 10

Prediction of Change: an inference about the conditions and behavior of the variables in the future. Using the graph you created on the previous page, can you predict what the temperature might be at time 15 minutes? The temperature should be about 45oC.

Dynamic Equilibrium: When opposing environmental variables cancel each other out reaching a point where both variables are the SAME (equal).

Do Now: Describe the objects on the desk. Infer what you think will happen when the Coke/Pepsi can is placed in the water? Infer what you think will happen when the Diet Coke/Diet Pepsi can is placed in the water? What actually happened?  What do you think is responsible for the outcome you observed?

Coke Diet Coke

Density

Density

DENSITY = ----------------- The amount of MASS (stuff or matter) in a certain VOLUME (space). DENSITY = ----------------- Mass Volume

Density Triangle Only works if you know 2 of the variables! DMV in the triangle D = M / V M = D x V V = M / D Only works if you know 2 of the variables!

Mass: The amount of matter (stuff) an object contains. Usually measured with a balance.

Volume: The amount of space an object takes up. Can be (1) calculated or (2) measured with a graduated cylinder. To calculate the volume using a ruler: Volume = Length x Width x Height V = 3cm x 2cm x 4cm V = 24cm3

To measure the volume using a graduated cylinder: Pour water in a graduated cylinder & record the measurement. Drop in the object & record the new water measurement, then SUBTRACT! ml

Example in Notes

Practice Problems: Find the DENSITY of a rock with a mass of 200.8g and a volume of 15.4mL. Find the MASS of an object with a density of 17.3 g/cm3 and a volume of 26.9 cm3. D = M/V D = 200.8g / 15.4mL D = 13.038961g/mL D = 13.0g/mL 2. M = D x V M = (17.3g/cm3) x (26.9cm3) M = 465.37g M = 465.4g

Practice Problems: Find the VOLUME of an object that has a density of 12.7 g/cm3 and a mass of 253.7 grams. 3. V = Mass/Density V = (253.7g) / (12.7g/cm3) V = 19.976377cm3 V = 20.0cm3

What is the difference between the two units? Determining Relative Density: The density of water is ________ or _________ What is the difference between the two units? An object with a density LESS then 1.0g/mL will FLOAT in water. An object with a density MORE then 1.0g/mL will SINK in water. The density of water is 1.0g/mL or 1.0 g/cm3. What is the difference between the two units? An object with a density LESS then 1.0g/mL will FLOAT. An object with a density MORE then 1.0 g/mL will SINK.

Physical Changes that Affect Denisty: - Two things can change the density of an object: Temperature: Increase in temp will cause an object to expand (volume increases so DENSITY will ______________. Pressure: Increase in pressure will cause object to contract (volume decrease) so DENSITY will ______________. THE DENSITY OF AN OBJECT WILL NOT CHANGE UNLESS YOU CHANGE THE TEMPERATURE OR PRESSURE!! 1. Temperature: Increase in temp will cause an object to expand (volume increases) so DENSITY will DECREASE. Pressure: Increase in pressure will cause object to contract (volume decrease) so DENSITY will INCREASE.

The amount of space a substance occupies is called __________________. Questions: The amount of space a substance occupies is called __________________. An empty 250mL beaker has a mass of 60g. When 100mL of oil is added to the beaker, the total mass is 140g. Determine the density of just the oil. The amount of space a substance occupies is called VOLUME. An empty 250mL beaker has a mass of 60g. When 100mL of oil is added to the beaker, the total mass is 140g. Determine the density of just the oil. D = M/V D = (140g-60g) / 100mL D = 80g/100mL D = 0.8g/mL

A student mixed several different types of beads that all have a size of 12mm. They were lucky that the beads had different densities. One group of beads had a density of 0.6g/cm3; the other beads had a density of 1.2g/cm3. Describe a method that the student can use to sort the beads? 3. The student can fill a container with water, which has a density of 1.0g/cm3. They may then place all of the beads in the water. The beads with a density of 0.6g/cm3 will float, while the beads with a density of 1.2g/cm3 will sink.

Which material has the greatest density; Explain how you know? Draw the line which would represent the density of water. Since you know the density of water, which of these materials will float; Explain how you know? 3a) Material A has the greatest density because it has the steepest slope. 3c) Material D will float in water because it has a density less then waters.

Using the container to the right which is filled with water, list the four materials is order of INCREASING Density. Which of the four materials has a density closest to water? Explain how you know.