What is the difference between a vector and magnitude

"Magnitude" just means "size" so all numbers have a magnitude. 3 has a greater magnitude than 1, and 10 has a greater magnitude than 3.

In physics we classify our quantities as either "scalars" or "vectors". Both scalars and vectors need to have a unit to go with them to show what we've measured and how big it is. For example if I tell you the distance from my house to the shop is 38, you have no idea how far it is. If I tell you it's 38 meters, you know that's different to 38 miles or 38 feet.

Vectors are quantities which have a magnitude and also a direction (and a unit). We use this when the direction matters (and makes sense), for example if I travel 2 miles North I end up in a very different place to if I travel 2 miles South. The direction matters to my position.

Scalars are quantities which only have a magnitude, and a unit. We use these when direction doesn't matter or make sense. For example, it would make no sense to say I have 1 litre of water South, I just have 1 litre of water.

Sometimes in everyday language we use vectors and scalars interchangeably. For example if I drive in my car at 30 miles per hour, I'm telling you the speed of my car, a scalar quantity. If I tell you instead that I'm travelling at 30 miles per hour due East, I'm now telling you the velocity of my car.

Hope that helps!

Ooo this is a good one, for the purpose of understanding to pass exams assignments, etc: It is just direction and power. I always thought of it as I point in a certain direction (Vector) and then I push (Magnitude).