Measurement Precision and Unit Conversion

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Questions and Answers

What is the primary role of alkalinity in seawater?

To stabilize pH by neutralizing acids and bases (correct)

To increase the concentration of H+ ions

To dictate the color of seawater

To measure the temperature of the ocean

What happens when carbon dioxide levels in the ocean exceed its buffering capacity?

The pH of the water increases

Carbonate shells begin to dissolve (correct)

Sea temperature decreases significantly

The ocean becomes more alkaline

Which of the following best describes the buffering equation for pH in water?

It involves the reaction between water and carbon dioxide (correct)

It generates energy for marine life

It removes oxygen from the ocean

It leads to an increase in temperature

What type of sediments are associated with moderate-energy waters such as beaches or rivers?

Sand Signup and view all the answers

What is the main cause of increased carbon dioxide levels in the atmosphere?

Burning fossil fuels for energy Signup and view all the answers

What is the isobath interval?

The difference in depth between consecutive isobaths. Signup and view all the answers

What does an index isobath represent on a map?

A thicker, darker isobath line that indicates a major depth. Signup and view all the answers

How are isobaths spaced in relation to slope steepness?

They are farther apart on gentle slopes and closer on steep slopes. Signup and view all the answers

Which of the following is true about isobaths?

Isobaths must not be interpolated for depth between them. Signup and view all the answers

If a map has an isobath interval of 20 feet, what does a 100-foot index isobath indicate?

It is written at every 5th isobath. Signup and view all the answers

Which type of rock is primarily formed from heat and pressure applied to existing rocks?

Metamorphic rock Signup and view all the answers

What does a 20-feet isobath interval imply about the isobath lines on a map?

All isobath lines are 20 feet apart in depth. Signup and view all the answers

Which statement correctly identifies the characteristic of isobath lines?

Isobaths bend and V upward for valleys and canyons. Signup and view all the answers

What is the equivalent of 1 g/mL in terms of another density unit?

1 g/cm3 Signup and view all the answers

How should you round a sum of 12.6 cm and 3 cm?

16 cm Signup and view all the answers

What is the error margin acceptable for measuring salinity?

+/- 0.5 ‰ Signup and view all the answers

How is the refractive index of liquids measured?

Using a refractometer Signup and view all the answers

What must be true about the precision of an instrument in relation to the measurement error?

The measurement error can sometimes be greater than the precision of the instrument. Signup and view all the answers

What angle denotes the position when facing South in a clockwise measurement from North?

180° Signup and view all the answers

If an oceanographer measures an angle with an error of +/- 2°, what is the range for an angle measurement of 100°?

98° to 102° Signup and view all the answers

If a thermometer reads 22.4°C but is precise only to the tenths place, what would be an appropriate error to report?

+/- 0.2°C Signup and view all the answers

Which of the following describes longitude?

Lines between the poles measuring angular distance Signup and view all the answers

Which step is NOT part of the unit conversion technique outlined?

Add any necessary conversion factors. Signup and view all the answers

When rounding a measurement, how should you determine the precision of your final answer?

Use the least precise measurement from your input data. Signup and view all the answers

What is the latitude of San Francisco?

38° North Signup and view all the answers

What should you do if you have no error provided with a measurement?

Assume an error based on the instrument’s precision. Signup and view all the answers

What is the key reason for using conversion factors in unit conversion?

To allow for canceling out the original unit. Signup and view all the answers

How does measuring error generally relate to precision when dealing with human measurement?

Error may override instrument precision due to human factors. Signup and view all the answers

When rounding a calculated result involving multiple measurements, what is the basic rule to follow?

Round to the precision of the least precise measurement. Signup and view all the answers

Which of the following best describes the Prime Meridian?

An imaginary line that connects the poles and intersects Greenwich, England. Signup and view all the answers

What occurs at divergent plate boundaries?

New seafloor forms as plates move away from each other. Signup and view all the answers

Which type of plate boundary is associated with the formation of explosive volcanic eruptions?

Convergent boundaries Signup and view all the answers

What is the significance of the International Date Line?

It serves as the opposite longitude line to the Prime Meridian. Signup and view all the answers

Which statement about transform boundaries is correct?

Plates slide past each other, resulting in earthquakes but no volcanic activity. Signup and view all the answers

In relation to latitude and longitude, which of the following formats is correct?

24.6° N, 56.2° W +/- 0.2° Signup and view all the answers

Which feature is primarily formed by convergent boundaries?

Deep ocean trenches Signup and view all the answers

What do isobaths on bathymetric charts represent?

Points of the same depth on the ocean floor. Signup and view all the answers

Study Notes

Error, Precision, and Rounding

All measurements are subject to error, and this error is represented by +/- the smallest graduation of the measuring device (precision).
Error is assumed to be +/- 1/2 the measurement of the next number or decimal place, unless otherwise specified.
Round answers to the same precision as the least precise measurement used in the calculation.

Unit Conversion

Convert units by multiplying a fraction representing the original number by a conversion factor fraction.
The conversion factor fraction should have the unit you want to cancel out in the denominator and the unit you want to end with in the numerator.
Round answers to the same precision as the least precise measurement used in the calculation.

Reading a Refractometer

Measures the refractive index of liquids, which is directly related to density and salinity.
Salinity is measured in parts per thousand (‰) and has a precision of 1 ‰, with a minimum error of +/- 0.5 ‰.
Density is measured in g/mL and has a precision of 0.001 g/mL, with a minimum error of +/- 0.0005 g/mL.

Angles & Compasses

A circle is divided into 360 degrees (360°).
Angles are measured clockwise from North (N) using a protractor.
Always attach an error to your angle measurements (e.g., +/- 2°).

Latitude and Longitude

A system of angular coordinates used to uniquely locate a point on Earth's surface.
Latitude measures angular distance north or south of the Equator (X-axis).
Longitude measures angular distance east or west of the Prime Meridian (Y-axis).
The International Date Line (Antimeridian) is located at 180° longitude.
Example format for latitude and longitude: 24.6° N, 56.2° W +/- 0.2°

Plate Boundaries

Divergent boundaries: plates move apart, creating new seafloor, shallow and weak earthquakes, volcanic seamounts, and lava flows.
Convergent boundaries: plates move towards each other, creating subduction zones (denser plate sinks) or continental collisions (tall mountain ranges).
Transform boundaries: plates slide past each other, generating earthquakes but no volcanoes, trenches, or new seafloor.

Bathymetric Maps & Isobaths
Bathymetric maps show depth to the ocean floor using lines connecting points of equal depth (isobaths).
Isobaths are like shorelines if sea level were to drop.
Isobath interval is the difference in depth between two isobaths.
Index isobaths are darker, thicker lines labeled with depth values, occurring at regular intervals.

Marine Rocks

Sedimentary rocks: formed from pre-existing sediments (sand, mud, shells).
Igneous rocks: formed from the cooling and solidification of molten rock (magma or lava).
Metamorphic rocks: formed from existing rocks that have been transformed by heat and pressure.

Ocean Chemistry

*pH scale: measures the acidity or alkalinity of a solution, ranging from 0 to 14 (7 is neutral).
Buffering: seawater's ability to resist changes in pH due to the presence of dissolved ions like carbonates.
Ocean Acidification: increasing CO2 levels in the atmosphere lead to a decrease in oceanic pH, dissolving calcium carbonate structures like shells and coral reefs.

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Description

This quiz covers key concepts in measurement precision, unit conversion, and the use of a refractometer. You'll learn about error representation, rounding methods, and how to accurately read and interpret refractive index measurements relevant to density and salinity. Test your understanding of these essential scientific principles.