Basic Question - Mass vs Weight

Oct 2018
My daughter had a question from school and it confused me.
The question reads:
True of False; Both weight and mass measure how heavy (or light) an object or a substance is.

My daughter circled false and I agree with her. But she missed that question.

Mass is different than weight. Weight changes depending on where you are and mass stays constant.

Can anyone help? Thank you!
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Aug 2010
I really don't like the way this question is worded! Exactly what is intended by "measure how heavy"?
Apr 2017
Yes ... the question is designed to confuse , as many are.

The unseen people who created the education system have the aim of dumbing people down , preventing learning ...Search " The Deliberate Dumbing Down of America": A Chronological Paper Trail
Book by Charlotte Thomson Iserbyt

But lets look at the question
"True of False; Both weight and mass measure how heavy (or light) an object or a substance is..."

"Heavy" is a measure of force .... units are Newtons

Is weight a measure of force ???? .....YES

Is mass a measure of force ???? ....Most definitely NOT! units are Kg

So beyond all doubt the correct answer is FALSE
Last edited:
Oct 2018
Thank you oz93666!

I will keep an eye on her schooling so she doesn't become one of the "dumbing down." HAHA

I have yet to hear from the teacher, but I will update this post with her response.
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Oct 2017
Mass is no longer a good indicator of heaviness if you consider a sample of objects at different locations and those locations have different local gravitational field strengths. Therefore, generally speaking, the answer is false.

However, if you take a sample of objects at the Earth's surface where g is constant, both weight and mass measurements are an indication of the heaviness of something. The question presumably has this assumption and a better worded question would state it. At the sort of level of schooling you're talking about, chances are the context of every question is something happening on the Earth's surface using "normal" everyday conditions, so it's a reasonable assumption.
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Apr 2015
Somerset, England
I am not american but I see that the average age of 5th graders is 10/11.

I well remember at that age in an English school being slapped down following a BBC science programme for schools, where the presenters said

"An object floats because it is lighter than water and sinks because it is heavier than water."

When our teacher asked the class "Why does something float" I put up my hand and said

"Because it is less dense than water" and was told I was wrong.

In England few teachers of that age group have any science at all to their name.
Most are nice people who like looking after smaller children (and keeping them quiet).
These days some are PE specialists and so on.

So to your question.

No the school were wrong and your daughter was right.

I hope she can take this incident in her stride and it does not put her off science.

When she is older they will tell her a better story.
Jun 2016
Looks to me like one of those questions where by trying to simplify the sentence used,
the precision needed was lost.
If the sentence was:
Both weight and mass indicate how heavy (or light) an object or a substance is.
Then we could accept that as true.
however the term "measure" has particular connotations which encompass the units in which the quantities are measured,
Thus weight is (properly) measured in Newtons and Mass in Kilograms (which are different beasts)

These two qualities are related by the proverbial F=ma
Replace the acceleration term by the acceleration due to gravity (F=mg) and you have an expression relating Mass to Weight.

Note that the assumption that "g" is constant is not entirely true.
The Earth is not a perfect sphere so "g" varies with latitude,
it also varies with local geology.

So weight will be different when measured at the north pole or at the equator,
but mass will be the same.
Apr 2015
Somerset, England
Both weight and mass indicate how heavy (or light) an object or a substance is.
There's more to it than that.

What is the weight of an object floating in water compared to standing on the table?

What is the mass of that object floating in water compared to standing on the table?


PHF Hall of Fame
Apr 2009
Boston's North Shore
Woody is referring to the fact that the greater your mass is the greater your weight is and vice versa. We often determine the mass of a substance by how much it weighs. I.e. W = Mg. Therefore M = W/g. In chemistry we always determined mass using a weight scale (calibrated for earth).

BTW - Woody said that mass indicates weight, not is weight.