Amarilis

Weighing in on Mass

By Karen Lohnes



Beach rocks

Look at a flower, rocks or even a soccer ball.  What are these items made of?  If you guessed matter, you are correct.  Matter  is anything that has mass and takes up space.  Can you name other items that have matter?



The many forms of water. Pond surrounded by snow.

Matter comes in all shapes, sizes and color.  Matter has three principles, it can be a solid, liquid, and gas.  So, let's look at water.  Water is considered a liquid state at room temperature, but put water in the freezer it becomes a solid, ice and hard and cold.  On a hot summer day water becomes vapor, an invisible gas.   Can you think of any other matter that changes states?



Good Harbor Beach

There are two types of matter, it is either a mixture or a pure substance.  A mixture  consists of two or more pure substances are are combined together.  They are not chemically combined.  For examples, combining salt and pepper, you can see the individual substances and they are not combined.  Sea water is a mixture of salt and water and is called a solution , a type of mixture.


Pure substances , you are probably wondering what is this?  A pure substance is made of only one type of matter.  It has specific properties .  Examples of pure substances include salt, copper, iron.  The properties of a pure substances will never change.

Properties are characteristics that never change from the matter.  They help identify the matter.  


Sea Salt


How do we measure matter?  When you measure matter you are obtaining the mass of an object.  The mass  of an object is how much matter is in the object.  It sounds simple, right.  But, did you know weighing matter the weight of an object can change because of its relationship to gravity.  So, if you weigh yourslef on a scale here on earth, you took a trip to the moon and weighed yourself on the moon, would you weigh more or less on the moon?  (See the coach for more information)

To measure the amount of space that matter takes up is called its volume .  Solids, liquids and even gases have volume.  We will get more into volume in the next book.  So, keep thinking, mass and weight of matter.



You measure mass with a balance scale.  To find a weight of an object you measure it on a spring scale.  Spring scales measure the force pulling down upon the object which is affected by gravity  .  The only time the mass and weight of an object would be the same is at sea level where the gravity is the strongest.



The scale at your doctor's office is a balance scale.  So in the scientific term you are being massed, not weighed.  This is where it gets confusing because they say they are weighing you.  If they were using a spring scale to weigh a person than gravity would affect the person's weight depending on the altitude of the location.



If you go to the grocery store you are getting the weight of an object because you are using a spring scale and gravity is pulling the object down.