Science 10

Lab Investigation

Title: Where Did You Say it Was?

Background: The instant you take a step you're moving a certain distance in a certain direction. How can we tell our friends where we went on a hike? How can we give directions to someone looking for the mall? We use scalars and vectors. A scalar indicates how far we went; a vector indicates how and in what direction we moved. On the open ocean for example, with no landmarks, knowing distance and direction are crucial.

Process:

1. Get a compass and a meter stick. The compass has three key parts: the needle suspended in its fluid-filled circular chamber, a plastic base stamped with a N arrow, a white wheel surrounding the needle chamber. Move to a section of floor where you can identify "start" and "finish" tiles.

2. The compass must now be aligned with the Earth's N pole. Place the compass on the "start" tile and note in which direction the N end of the needle points. Turn the plastic base of the compass so its "N" arrow points in the same direction. Keeping the compass base stationary, turn the white wheel so its N mark is also pointing N. Be sure the N end of the compass needle, the N arrow on the compass base and the N mark on the white wheel are all lined up and actually pointing N!

3. Look carefully at the white wheel and read the direction from the "start" tile toward the "finish" tile.

4. Measure the distance between the two tiles.

Questions:

1. Why did the compass need to be aligned?

2. a) What is the distance between the two tiles?

b) The direction from the first to the second tile?

3. a) How would you give information about the second tile as a scalar?

b) As a vector?