What is a vector or a scalar quantity?

To help you to understand a little bit about scalar and vector quantities, imagine this scenario. You want some juice to drink, so you ask your sibling if there is any in the fridge. Her reply is yes, there is juice. But, you’re a juice lover and you want to know more information, like how much juice there is and what flavour. So you either get annoyed because she didn’t give you all the information or you ask specifically these questions. For you, in your world all this information is important. It’s just not enough to say, yes there is juice.

Similarly in the scientific world, it is not enough to just state a quantity by giving only the magnitude and its units. Sometimes more information is needed. For instance when talking about the movement of a hurricane, it’s not enough to say the hurricane is moving at 5 miles per hour, the next piece of information that is absolutely important to you is the direction. Is it moving in a northerly direction  and therefore heading towards you or is it moving in a southerly direction away for you? The direction is important so you would know if you would be affected. In the same way some quantities are just incomplete if they do not have the direction attached to them. These quantities are called vector quantities.

A vector quantity is one that is described fully by stating both its magnitude and direction

Those quantities that can be described fully with magnitude only are called scalar quantities. For example it is sufficient to say that the mass of an object is 5 kg. No more information is necessary.

Scalar quantities are described fully with magnitude only

Drag each of these quantities to its corresponding box depending on whether it is a scalar or a vector.

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