MATTER, MASS, AND WEIGHT
MATTER – All objects (everything!) is made of matter. Matter is an old word. Today we know that matter is up of atoms. There are 92 different naturally occurring atoms that we’ve identified. But they all have the same basic parts (protons, electrons, neutrons). Some examples of atoms are hydrogen, oxygen, carbon, iron, and chlorine.
Can you name 6 other atoms? ______
What are molecules? ______
MASS - Mass is a word which means how much matter an object contains. So it really means how many and what kinds of atoms does an object contain. For example a small piece of iron contains 6 x 1023 iron atoms. This is not an unreasonable number!! Atoms are unimaginably small.
How could you compare the mass between 2 objects? ______
______
WEIGHT - One way to measure the difference in mass between 2 objects is to weigh them and see which is heavier. But this presumes that both objects are weighed under the same local gravity! This wasn’t a problem until humans started going into space and the moon where gravity can vary! For example the moon is 1/6 the mass of the Earth and therefore has 1/6 the gravity. Objects weigh 1/6 on the moon compared to what they weigh on Earth. So a rock that weighs more than a piece of wood on earth might weigh less on the moon!
Weight is really a measure of the pull of gravity on an object’s mass. Since gravity changes as one moves around the universe an object’s weight changes. But an object always has the same mass no matter where it is weighed. It is always made of the same kind and number of atoms.
THE MOST IMPORTANT RULE ABOUT GRAVITY: Gravity is associated with MASS and the more mass an object has, the greater it’s gravity.
Which planet has more mass Jupiter or Earth? ______
Which has more mass a grain of sand or a speck of dust? ______
Where will gravity be stronger Jupiter or Earth? ______
Which will have stronger gravity the grain of sand or the speck of dust? ______
Which has more mass a 30 kg rock or a 40 kg rock (both rocks were measured on the Earth) ______
Which has more weight a 60 kg rock measured on earth and taken to the moon and weighed again on the moon, or a 10 kg rock measured on the moon? ______
If you went to the moon how would your mass and weight change? ______
How fast is a 30 kg rock falling after 10 seconds? (a = 9.8 m/s2)______
Using F = ma, show that a 100 kg rock hits the ground with more force than a 10 kg rock.