UNDERSTANDING GRAVITY

UNDERSTANDING GRAVITY LESSON

Directions:

Print the Understanding Gravity reading comprehension passage and questions (see below).

Older students should read the passage silently, then answer the questions.  Teachers may also use the text as part of a classroom lesson plan.

Lesson Excerpt

Gravity is a force of nature that works between two bodies of matter in the universe to try and pull them together. The best example possible to explain gravity is to look at a person. You are a body of matter. The earth is also a body of matter. Gravity pulls you down to the earth and allows you to walk around instead of floating.

The moon has less amounts of gravity then the earth does so if you were to go on the moon you would bounce and float rather than walk. You would also weight a lot less because the lack of gravity would make your body weight change. Weight change occurs because the matter would be much denser then it is on the earth. While you are on earth gravity will stop you from floating away. However, the further you get from earth the more problems you would have staying on the ground.

Mass and Weight

Many people will use the words mass and weight as if they mean the same thing. Well, this isn't true when you are working with properties of gravity. Mass is the total amount of space your body takes up. Your mass is not going to physically change no matter where in the Universe you go. Your body will still be made of the same things. You will still be the same shape you are on earth. The only time your mass will change is when you grow bigger in both height and weight. When your weight or height increase or decrease your body mass changes shape.

Weight deals primarily with gravity. The amount you weigh is based on the force of gravity as it pulls you down towards the earth. The stronger the pull of gravity is on a planet the more you will weigh. You can see the chart below to get a better understanding of how weight changes on different planets. Keep in mind that the higher the number the stronger the gravitational pull is.

In our example, 11 year old Sam weights 70 lbs. The table shows Sam's weight on all of the planets in our universe as well as his weight on the moon. (continued...)