Explorer Tools

Astrolabe - An astrolabe is an instrument that can be used for measuring the position of large celestial bodies. It is made of a circle, that is marked off in degrees, with a arm that can move, that is placed in the center of the circle. This was used to measure latitude.

Chip board - A chip board is tied to seven hundred feet of rope rolled on a spool. The rope has knots tied in it at regular intervals. When the chip board was thrown over the stern of the vessel into the sea, sailors would count the knots as the rope unwound. The number of knots told them the speed of the ship.

Compass - A compass was used to find direction If they knew their direction and speed, they could estimate their location.

Cross Staff - The cross staff was used to measure the angle between the north star and the horizon. The higher the north star, the farther north they were. This is how they found latitude.

Hour Glass - An hour glass is a tool used to measure time. This was used to calculate speed.

Quadrant - The quadrant was used to find latitude by measuring the angle between the horizon and the sun. It was also used to find the distance away from an object of a known height.

Traverse Board - The traverse board was used to record the course and speed of a vessel during a four hour watch. The speed was measured using the chip log, and the direction was taken from the compass.

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Dawn, Dias, da Gama, Columbus, Vespucci, Magellan, Tools, Credits & Bibliography

	Astrolabe - An astrolabe is an instrument that can be used for measuring the position of large celestial bodies. It is made of a circle, that is marked off in degrees, with a arm that can move, that is placed in the center of the circle. This was used to measure latitude.
	Chip board - A chip board is tied to seven hundred feet of rope rolled on a spool. The rope has knots tied in it at regular intervals. When the chip board was thrown over the stern of the vessel into the sea, sailors would count the knots as the rope unwound. The number of knots told them the speed of the ship.
	Compass - A compass was used to find direction If they knew their direction and speed, they could estimate their location.
	Cross Staff - The cross staff was used to measure the angle between the north star and the horizon. The higher the north star, the farther north they were. This is how they found latitude.
	Hour Glass - An hour glass is a tool used to measure time. This was used to calculate speed.
	Quadrant - The quadrant was used to find latitude by measuring the angle between the horizon and the sun. It was also used to find the distance away from an object of a known height.
	Traverse Board - The traverse board was used to record the course and speed of a vessel during a four hour watch. The speed was measured using the chip log, and the direction was taken from the compass.