The position and direction of motion an object has is described using units. In order to communicate this information scientists need to share which system of units they are using in order to understand the behavior of an object. Created by Khan Academy.
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- Why is it called SI units when 'SI' stands for International System? Shouldn't they be called IS units?(13 votes)
- SI actually stands for the French “système internationale”, and it just gets abbreviated that way in all languages.(46 votes)
- Khan is still thriving even after the accounts I made ~4-6 years ago, glad to still see an active community(17 votes)
- Why are their different units for the same thing. Like feet and inches? Why can’t we just use one?(5 votes)
- When people ask how old you are, stop telling them how many years old you are, start telling them how many days old you are.(15 votes)
- Are there other units in physics?(5 votes)
- 1:00She's a better drawer than I am(6 votes)
- I know American scientists use SI/metric, but I feel like if the U.S. was a person they'd be in the corner stifling their laugh at2:31(6 votes)
- She says that we all know how long a meter is, but Americans aren't taught the metric system in school - we're taught imperial. So how would an American know how long a meter is? We use inches, feet, yards, etc.(5 votes)
- I think we used our base tens system to create a meter starting with, millimeters, centimeters then inches and after that is meter's. Also you use different words for different activities, such as you use cup/teaspoons for baking. Not to mention we have the internet for that answer. ( I hope this helped at least a tad bit. )(2 votes)
- what are the other units ?(2 votes)
- I like to eat food(4 votes)
- [Illustrator] Did you know that communication is actually one of the most important things in science? As we discover cool things, we need to be able to share them with others. And when we're talking about data and measurements with other scientists, we need to make sure we're on the same page. So how do we do that? Well, one of the ways is to use units. We use units whenever we talk about things like position, where an object is located, how long it is, it's mass, how much matter it's made up of or it's motion. How is that object moving? You probably hear units every day. For example, you've grown, let's say an inch and a half in the past year, or that tree over there is 25 feet tall. And maybe you went swimming in a 25 meter pool. And we're just gonna pretend that the pool is a rectangle because as you can tell from my tree, my artistic skills are not that great. Anyway, this brings up a super important point about why we use units. I just used three examples of length measurements with three different units, inches, feet, and meters. Imagine if I didn't attach a unit to any of these measurements, you grew one and a half, what? Meters? Whoa, one and a half hands. Well, whose hands? Your hands or my hands? Woof, well, pretend those are hands. Units let us know how much of a quantity there is. So a meter is always used to measure length and we know exactly how long a meter is. That way when we say something is two meters long, no one has to guess at how big that is. Any measurement or data point always needs to have a unit or else it's just a meaningless number. To avoid any confusion, in science we use what are called SI units. SI units are the International System. Could there be any more letters in this word system used by scientists all over the world. We'll use meters to describe position or length, kilograms for mass, and if we're talking about the motion of something, meters per second. And while this is the agreed upon scientific unit system, you should be aware that other systems do exist, which means things can very easily get very confusing if you forget your units. And you might be thinking, "Oh, come on, who mixes up units?' Well, it happens more often than you think, even rocket scientists have done it. I mean, a Mars Orbiter actually crashed due to a mix up in units. Now seriously, that actually happened, look it up and remember to use your units.