Question

List three units for mass (or weight) and give one example for each (i.e., list an object and its mass, or weight, expressed in that unit).

Short answer

Units of mass: Kilograms (e.g., 1 kg of rice), Grams (e.g., 1 g paperclip), Pounds (e.g., 10 lb cat).

Step-by-step solution

Listing the Units

Identify three different units of mass. Common units for mass include: the kilogram (kg), the gram (g), and the pound (lb).

Providing Examples for Each Unit

Provide an example of an object with its mass for each unit.For kilograms: A small bag of rice might weigh around 1 kg.For grams: A paperclip typically weighs about 1 g.For pounds: A domestic cat might weigh around 10 lb.

Key concepts

Kilogram

The kilogram, symbolized as 'kg', is the base unit of mass in the International System of Units (SI). It's equivalent to the mass of the international prototype of the kilogram, a platinum-iridium alloy cylinder housed at the International Bureau of Weights and Measures in France. One kilogram can be imagined as the mass of a liter of water, which is close to the mass of a textbook or a professional basketball.

For a clearer mental image, let's consider a common household item: a bag of sugar is often sold in 1 kg increments. So, when you're holding a standard bag of sugar, you're essentially holding one kilogram. This is a helpful reference as we employ these units in day-to-day life as well as in scientific contexts.

Gram

A gram, denoted as 'g', is a unit of mass that is one-thousandth of a kilogram. In the SI system, the gram is not a base unit (kilogram is), but it is widely used for smaller measurements. It's equivalent to the mass of one cubic centimeter of water at its maximum density, which is practically the mass of a small paperclip.

Other common examples include a teaspoon of salt, which typically weighs about 5 grams, or a small coin such as a U.S. penny, which weighs around 2.5 grams. Understanding how a gram feels by relating it to everyday items helps us make sense of this small unit of mass.

Pound

The pound, abbreviated as 'lb', is a unit of mass used in the imperial system, predominantly in the United States. One pound is officially defined as exactly 0.45359237 kilograms. To put this into perspective, a standard loaf of bread or a professional football might weigh approximately a pound.

To visualize it, consider a bag of flour, which commonly comes in a 5 lb bag. When you pick this up, you're handling five pounds of mass. The pound is a practical unit for everyday use in countries still using the imperial system, and understanding it is crucial for following recipes, measuring body weight, or even in shipping where weight affects costs.

Mass Measurement Examples

Mass measurement is part of daily life, and examples are everywhere. One can appreciate the different scales of mass measurement by considering a variety of objects. For instance:

• A microchip might weigh just a few milligrams (mg), a sub-unit of the gram.
• A textbook might weigh about 1.5 kg, comfortable to carry in a backpack.
• A standard watermelon could be close to 5 kg, hefty enough to require some effort to lift.
• An adult human's weight might be about 70 kg or approximately 154 pounds (lb).
• A car's weight can be measured in tons, where one ton is equivalent to 2000 lbs or about 907 kg.

Noticing these everyday examples helps anchor abstract units of mass in concrete reality, enhancing understanding and appreciation of how we measure the physical world around us.