Question

Earth Science Elevations are measured from sea level, which is considered to have an elevation of 0 feet. Elevations above sea level are positive, and elevations below sea level are negative. In Exercises \(9-13,\) use this table, which shows the elevation of the lowest point on each continent. $$\begin{array}{|l|c|r|} \hline \text { Continent } & \text { Location of Lowest Point } & \text { Elevation } \\ \hline \text { North America } & \text { Death Valley } & -282 \mathrm{ft} \\ \text { South America } & \text { Valdes Peninsula } & -131 \mathrm{ft} \\ \text { Europe } & \text { Caspian Sea } & -92 \mathrm{ft} \\ \text { Asia } & \text { Dead Sea } & -1,312 \mathrm{ft} \\ \text { Africa } & \text { Lake Assal } & -512 \mathrm{ft} \\ \text { Australia } & \text { Lake Eyre } & -52 \mathrm{ft} \\ \text { Antarctica } & \text { Bentley Subglacial Trench } & -8,327 \mathrm{ft} \\ \hline \end{array}$$ Copy the number line at left. Plot each elevation given in the table, and label the point with the name of the continent.

Short answer

Draw a number line, plot elevations, and label each point with the corresponding continent.

Step-by-step solution

- Draw the Number Line

Draw a horizontal number line with clearly marked intervals. Make sure the number line includes both positive and negative values that cover the range from Antarctica's lowest point (-8,327 ft) to the highest elevation near 0 ft.

- Identify Elevation Points

From the table, identify the elevation points for each continent: North America (-282 ft), South America (-131 ft), Europe (-92 ft), Asia (-1,312 ft), Africa (-512 ft), Australia (-52 ft), and Antarctica (-8,327 ft).

- Plot Points on the Number Line

Plot each elevation point on the number line. Place a point at -282 ft for North America, -131 ft for South America, -92 ft for Europe, -1,312 ft for Asia, -512 ft for Africa, -52 ft for Australia, and -8,327 ft for Antarctica.

- Label the Points

Label each plotted point with the corresponding continent name near the point you plotted on the number line.

Key concepts

Negative and Positive Integers

Understanding negative and positive integers is key for working with real-world data, such as elevations. Positive integers are numbers greater than zero and represent elevations above sea level. Examples include 1, 2, and 3. Negative integers are numbers less than zero and represent elevations below sea level. Examples include -1, -2, and -3.
In Earth Science, elevations are measured relative to sea level, which is set at 0 feet. Thus:

• Elevations above sea level are positive integers (e.g., 50 feet, 150 feet).
• Elevations below sea level are negative integers (e.g., -100 feet, -300 feet).

Knowing how to work with both positive and negative integers helps in understanding elevation changes and geographical data.

Number Line Plotting

Plotting numbers on a number line helps visualize their relative positions, including positive and negative values. To create a number line for elevations:

• Draw a horizontal line and mark intervals at equal distances (e.g., every 500 or 1,000 feet).
• Label the center as 0 feet (sea level).
• Mark positive intervals to the right (above sea level) and negative intervals to the left (below sea level).

:
For example, step-by-step number line plotting for elevations: Place a point at -282 feet for North America, -131 feet for South America, -92 feet for Europe, -1,312 feet for Asia, -512 feet for Africa, -52 feet for Australia, and -8,327 feet for Antarctica.
This visual aid makes comparing elevations straightforward.

Geographical Data Representation

Representing geographical data visually, such as on a number line, map, or chart, improves comprehension. In the context of elevations:

• A number line allows us to see the relative depths and heights easily.
• Maps help visualize the physical locations and topography.

In our exercise, we use a number line to plot the lowest elevations on each continent. Translating table data into a visual format like a number line makes differences and patterns more apparent.
For example, you can quickly see that Antarctica has the deepest point at -8,327 feet, while other continents have much shallower low points compared to it.

Continental Low Points

Continental low points are the lowest elevation points found on each continent. Here are some continental low points and their elevations:

• North America: Death Valley at -282 feet
• South America: Valdes Peninsula at -131 feet
• Europe: Caspian Sea at -92 feet
• Asia: Dead Sea at -1,312 feet
• Africa: Lake Assal at -512 feet
• Australia: Lake Eyre at -52 feet
• Antarctica: Bentley Subglacial Trench at -8,327 feet

These elevations show how diverse Earth's geography can be. For instance, the Bentley Subglacial Trench in Antarctica is significantly deeper compared to other continents' low points. Understanding these differences is crucial for fields like geology and environmental science.