QWORK Plastic Tubular Spring Scale - 1N, 5N, 10N, 20N, 30N Capacity, Grams & Newton Calibration, Zeroing Capability, Clear Plastic Body Spring Balance Hanging Tube, Set of 5

A must have for all physics classes.

I don't know what to tell you. It measures weight. I don't know if its accurate or not but it seems about right. Meh. 5 stars. Why not. It's the best set of springs in tubes I own.

Buena calidad para el precio.

Accurate readings, inexpensive, newtons and grams—Do not leave in unoccupied student hands for extra time; they will dismantle it. Easily reassembled, though.

I needed to test tension and torque on several machines, with a variety of small and large ranges (200 grams to > 1kg). I tried a digital luggage scale for the large ranges but it was annoying since they are programmed to lock the measurement after a peak is detected. These spring scales are perfect for the job, since I can easily see the change over time and make a mental note of the peak when I find it. (If you've ever tried to understand a changing value using a digital multimeter, you'll get what I mean. An analog needle is so much more informative than a bunch of flickering digits.) I tested these scales with a range of weights (confirmed on other calibrated digital scales) and they were all close enough to be useful for me (within a few percent). The key to accuracy is selecting an appropriate scale range for your test: None of these will be accurate on the extreme low end of the range, so don't test a 50g weight on the 3kg scale. There are 5, so it's easy to find one that fits. The top of each scale has a zero adjustment, just turn the screw. The spring tension inside can be adjusted non-destructively (although you'd need some well-calibrated equipment to do so) and they were calibrated at the factory, not just assembled and shipped. The construction is decent. The clear tubes have some scuff marks but the markings are clear. The assembly stays together naturally since it's all hooks and gravity. The blue rings at the bottom of the tubes are press-fit (and maybe glued?) to the tubes, so you can take them apart if you wanted to. They have no effect on the measurement, just keeping the dust out. Overall, I'm impressed!