Question

Identify the SI unit that would be most appropriate for expressing the length of the following. a. width of a gymnasium b. length of a finger c. distance between your town and the closest border of the next state d. length of a bacterial cell

Short answer

a. meter (m); b. centimeter (cm); c. kilometer (km); d. micrometer (µm)

Step-by-step solution

Determine the suitable unit for the width of a gymnasium

A gymnasium is typically a large space, so the suitable unit for measuring its width is the meter (m), which is practical for large structures.

Identify the appropriate unit for the length of a finger

A finger is a small body part, often measured in centimeters (cm) to provide precision in recording smaller lengths.

Choose the correct unit for the distance between your town and the closest border of the next state

The distance between towns and state borders is usually quite large, making kilometers (km) the most appropriate unit of measure.

Select the correct unit for the length of a bacterial cell

Bacterial cells are extremely small, often requiring a unit like the micrometer (µm) to precisely measure such tiny lengths.

Key concepts

length measurement

Length measurement is essential in various scientific and everyday tasks. In the International System of Units (SI), there are different units to measure length based on the size and scale of the object. For example, larger structures like buildings are measured using meters, while extremely small objects like bacteria are measured in micrometers. Choosing the correct unit ensures accurate measurements and clear communication.

Here are typical SI units for length:

• Meters (m)
• Centimeters (cm)
• Kilometers (km)
• Micrometers (µm)

The step-by-step solution helped in determining which unit fits best for various measurements, from the width of a gymnasium to the length of a bacterial cell.

meter

A meter (m) is the base unit for length in the SI system. It is widely used for measuring medium to large distances and objects. For example, the width of a gymnasium is best expressed in meters because this unit provides a convenient scale to work with for large structures.

Here are some examples of when to use meters:

• Height of a building
• Length of a football field
• Width of a swimming pool

Using meters helps in easy and precise measurement, avoiding the impracticalities of using smaller units like centimeters for large objects.

centimeter

Centimeters (cm) are a smaller unit of length in the SI system, ideal for measuring smaller objects or distances. For instance, the length of a finger is usually measured in centimeters. This unit provides the precision needed for smaller measurements.

Here are when centimeters are useful:

• Length of a pencil
• Width of a book
• Height of a small plant

Using centimeters helps ensure accuracy in smaller scales, where meters would be too large and less precise.

kilometer

A kilometer (km) is used for measuring very large distances. In the SI system, it's equivalent to 1,000 meters. For example, the distance between a town and the closest border of the next state would typically be measured in kilometers.

Here are scenarios to use kilometers:

• Distance between cities
• Length of highways
• Separation between countries

Using kilometers allows for easier expression and understanding of extensive distances, making communication and calculations more straightforward.

micrometer

Micrometers (µm) are used for measuring extremely small lengths. One micrometer is one-millionth of a meter. For example, bacterial cells, which are tiny, are best measured in micrometers to ensure precision.

Here are situations to use micrometers:

• Measuring cells
• Thickness of thin films
• Size of microorganisms

By using micrometers, we can accurately measure tiny objects or distances that would be impractical to measure with larger units like millimeters or centimeters.