Students learn how to measure mass and weight.
After completing this tutorial, you will be able to complete the following:
Mass is the amount of matter in an object. Mass remains the same no matter where you are because the amount of matter in something does not change, even if the gravitational pull changes. The unit used to measure mass is the gram or kilogram. Scientists use a triple beam balance or a pan balance to measure mass. A triple beam balance consists of three beams with standard mass graduations. The highest beam has 100-gram graduations, the second has 10-gram graduations, and the third has 1-gram graduations. The mass of an object is found by sliding the weight along each beam until the balance pointer reaches equilibrium. The weights shown on each beam are then added together to determine the mass of the object. A pan balance has two separate pans, one at each end. To use the balance, an object of unknown mass is placed in one pan, and standard masses are put in the other until the pans reach equilibrium. The sum of the masses is then determined to find the mass of the object.
Weight is the force on an object due to gravity. If the gravity of an object changes, then the weight of that object will also change. An example of this is an astronaut on the moon. The astronaut will weigh less on the moon because the gravitational pull on the moon is less than that on Earth. A spring scale is used to measure weight. A spring fixed at one end has a hook on the other end to attach to an object. It works based on the principle that the force needed to extend a spring is proportional to the distance the spring extends from its resting position. The unit of weight is the newton. A dynamometer is used to measure force. It can also be used to determine the torque and power required to operate a machine that is driven.
|Approximate Time||20 Minutes|
|Pre-requisite Concepts||Students should be familiar with mass, weight, and the metric system.|
|Type of Tutorial||Concept Development|
|Key Vocabulary||balance, dynamometer, force|