Measurements: Mass vs. Weight

I am helping a first year teacher who is teaching science to children who are not fluent in English.

1. How does one explain that mass and weight are not interchangeable terms when  the same instrument, such as a  bathroom scale, can be used to measure both mass and weight?

2. How does one explain that mass and weight are not interchangeable terms when they must learn how to use the conversion factor, 454 g = 1 pound? Also, products, such as cereal, often have gram (g) and pound or ounce measurements printed on the package.

Actually, both questions apply to every science student in any language.

So, how does one present these two measurements?
When working with young children, I’ve been guilty of not distinguishing between the two very different types of measurements. But, I have had a change of attitude about what young children can learn.
In fact, kids of any age can learn new concepts if given  tiny “bite-size ” pieces of information and ample time to “chew it” before being expected to digest it.

1. The Weight of an object measures a special kind of force called gravity.

On Earth, prior to his Moon landing,  astronaut Buzz Aldrin’s weight with backpack and space suit was about 360 pounds.

On the Moon, July 20, 1959, Buzz Aldrin’s weight with backpack and space suit was about 60 pounds.

2. The mass of an object measure the object’s  inertia. Inertia measures how difficult it is to change the motion of an object.

Example 1:
Which would be harder to move,  a gallon bottle filled with water or a 50 gallon bottle filled with water?

Answer:
Think!
1. The object that has more inertia is harder to move.
2. The object that has more mass is harder to move.
3. Mass measures the amount of matter. Matter is what stuff is made of, such as atoms and molecules. Since both containers are filled with water, the container with the most molecules of water will be harder to move.

The bottle 50 gallon bottle of water has more water molecules, thus it has more mass, and more inertia than the one gallon bottle of water.

Examples:
If both are standing still, which would be easier to move, a real elephant or a small toy stuffed elephant?
Answer: Of course, the answer is the one that is less massive, the small toy stuffed elephant..

Janice VanCleave’s Play and Find Out About Math: Easy Activities for Young Children

Janice VanCleave’s Gravity: Spectacular Science Projects

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2. Mass and Size of Subatomic Parts
3. Gravity vs. Mass
4. Mass vs. Weight
5. Inertia vs. Mass
6. Center of Gravity vs. Center of Mass
7. Barycenter of Bodies of Unequal Mass
8. Using Inertia to Measure Mass
9. Mass: Equal-Arm Balance
10. Are Mass and Inertia Related?