Electronic scales can’t be nearly as accurate as balance scales. Why? Because the earth’s gravity varies by more than 0.5%, depending on where you are. That means that an electronic scale might show you weighing 200lbs in one location and 201lbs somewhere else.

Newton’s second law of motion (also known as the force law ) states that… net force is directly proportional to mass when acceleration is constant. …

Mass is a measure of how much material is in an object, but weight is a measure of the gravitational force exerted on that material in a gravitational field; thus, mass and weight are proportional to each other, with the acceleration due to gravity as the proportionality constant.

Gerry Dutton, from the Trading Standards Institute, says: ‘Since 2003 it’s been illegal for hospitals or GP surgeries to use domestic bathroom scales in medical situations: they’re inaccurate, hard to read truthfully and vary with a person’s standing position.

Sure, the human body fluctuates over the course of the day and there are some crappy scales out there, but even relatively good scales can seem to be wildly inaccurate. In general, digital bathroom scales are more accurate than mechanical ones.

No matter what the scale says, you’re the same size on each one. You don’t get bigger from being on a different scale. Regular home and shop/gym scales are a little bit imprecise, so they’ll often differ a little bit even if you try one seconds after the other, wearing the same clothes. It’s the scales, not your body.

If you have 2 scales (borrow one if necessary – You will only need to get your starting weight once), you can get a fairly accurate reading by putting a foot on both scales at once and adding the numbers for your total weight. …

Daily weight fluctuation is normal. The average adult’s weight fluctuates up to 5 or 6 pounds per day. It all comes down to what and when you eat, drink, exercise, and even sleep.

When a scale is gradually increasing or decreasing in weight on its own, it is experiencing drift. First, make sure that the scale is on a stable surface and that there are no outside factors that could be putting slight weight on the scale, like a fan or a busy work environment.

You’re constantly being pulled down by gravity, with a force equal to your weight. When you jump upward you do accelerate, so you know that the forces are no longer equal. Your weight is still the same, but the force transmitted by the floor (through the scale) has increased, so the dial reads higher.

The official physics-classroom answer is that it’s the same as before he jumped. That’s because weight is officially defined as the gravitational force, equal to , where is the mass (e.g., in killograms) and is the local strength of gravity (e.g., in meters per second per second).

Replace the bad load cell. If this is inconclusive, you will need to perform a calibration with the scale empty and then record the mV/V levels from the load cell(s). You can find the mV/V levels by going into the IT Weight and Voltage Test section of your Hardy controller.