Instruments are tricky to make and maintain. Unless there is a huge error in them it is very difficult to realize that something is wrong with them. For example, the weighing machine at your grocer has a slight error. It shows 1 kg of rice as 1.050 kg. Unless you are taking a huge quantity of rice, that error will never be caught by you or the grocer for that matter. Most of the gadgets and appliances we use are commercially mass built. Approximation is inherently built in them. Accuracy is always given a second priority in them. Let’s take a look at some of the gadgets you use every day that are not as reliable as you think they are. Cellphones lie about how much charge they hold Your phone never charges to a 100 percent. Because a fully charged battery degrades faster. That’s why the phones actually only charge until 95% and stop. But the phones cannot show you that it has charged only 95%, because then you will never plug it out. But it is for the phone’s safety, so chill out.

Fuel gauges will show that your tank is empty even when there is a bit of fuel in the tank.

Have you ever noticed that when you fill your tank full of petrol, the needle doesnt really leave the F mark for some time.

But as soon as the needle goes below the halfway mark, it starts dipping quicker than the first half. That is because analog gauges have a float mechanism to ascertain how much fuel is in the tank. The float is a ball and that is why when there is very little fuel left, the ball makes the needle touch E.

The digital gauges are not so smart either because most of them need regular calibration, otherwise they are going to show you an error that will leave you with an empty tank when there is still one bar left on the gauge.

Weighing scales are almost lethal in hospitals if they are wrong.

“What’s the big deal?”, one might say. It is just a kilo off the actual weight.

Yes, you are right. For regular people it is not a big deal at all. But if you are a cancer patient, and you have to undergo radiation therapy, you need to check your weight properly because you get radiation proportional to your weight.

If the weighing scale is wrongly calibrated you might end up getting a bit too much of it which may turn out to be harmful to you.

This is when doctors in US and UK launched an investigation to check all the weighing gauges in hospitals and found out that almost one-third of all the scales were innaccurate.