Beam to Moon (Ratios and Proportions)
Have you ever heard someone wish they could find a quick and easy way to lose weight?
The next time you do, just tell the person to go to the Moon! Of course, they will not lose
any mass, which is what they really want to do, but they will lose weight.
Your weight depends on the gravitational force pulling you down. Because the Moon is so
much smaller than Earth, its gravitational force is much weaker, and your weight on the
Moon will be much less than your weight on Earth. How much less? You can use
proportions to find out.
Calculating Weights on the Moon
Gravity affects all objects the same way. This means that the ratio of any object's weight
on the Earth to its weight on the Moon will always be the same. If you know the weight of
an object on the Earth and the Moon, you can use a proportion to find your weight on the
Moon as well.
1.
Enter your Earth weight into the box on the left side of the Gizmo™ and hit Enter
on your keyboard. Your weight will be displayed in the Person weight on Earth
space in the proportion at the bottom of the Gizmo.
2.
Drag the watermelon onto the scale on Earth. Its Earth weight will be displayed in
the proportion in the Object weight on Earth location. Then drag the watermelon
onto the first scale on the Moon. (Be sure Moon is selected in the dropdown
menu.) The watermelon's Moon weight will be displayed in the proportion in the
Object weight on Moon location.
a. How much does the watermelon weigh on Earth? _____________________
b. How much does it weigh on the Moon? _______________________
3.
a.
b.
c.
Since you have three of the four spaces in the proportion filled out, you can find
the fourth value (your weight on the Moon) by solving the proportion. Solve for
the unknown value in the proportion on paper. To check your answer, click Beam
Away.
How much do you weigh on Earth? How much would you weigh on the Moon?
_____________________
What is the ratio of your Earth weight to your Moon weight? (Round to the
nearest tenth.)
_____________________
What is the ratio of the watermelon's Earth weight to its Moon weight?
_____________________
d.
How does your ratio compare to the watermelon's ratio?
e.
_____________________________________________________________________
The stronger the force of gravity, the more you will weigh. Which has a stronger
gravitational force, the Earth or the Moon? Explain.
a.
_____________________________________________________________________
Beam yourself back to Earth by clicking Beam Home. Repeat the process with
the baseball and the flower to calculate your weight on the Moon.
What is the ratio of the Earth weight of the baseball to its Moon weight?
b.
_____________________________
What is the Earth weight to Moon weight ratio for the flower?
4.
c.
_____________________________
What do you think the ratio of the Earth weight to the Moon weight of a parakeet
would be? Of a skyscraper? Explain.
a.
_____________________________________________________________________
When you divide the Earth weight of any object by its Moon weight , the quotient
is always the same, regardless of what the object is. (Earth weight is about 6
times the Moon weight of an object. Or, Moon weight is about one–sixth of Earth
weight.) This means that Earth weight and Moon weight are proportional. Use
what you have learned to answer these questions:
If an object weighs 30 Newtons on Earth, how much would it weigh on the Moon?
b.
_____________________________
If an object weighs 30 Newtons on the Moon, how much would it weigh on Earth?
5.
_____________________________
Calculating Weights on Other Planets
Because gravity works the same way on other planets as it does on the Earth and Moon,
the weights of objects on other planets are also proportional.
1.
2.
a.
Beam yourself back to Earth if necessary.
Choose the planet Venus from the dropdown menu under the Moon scene, and do
the weighing experiments the same way as they were described earlier.
How much would you weigh on Venus?
b.
_________________________
What is the ratio of your Earth weight to your Venus weight?
c.
3.
a.
_________________________
Is the gravity on Venus stronger or weaker than that on Earth? Is it stronger or
weaker than the gravity on the Moon? Explain your answers.
_____________________________________________________________________
Run the weight experiment for all the planets in the dropdown menu.
Which planet has the strongest gravity? Explain your answer.
_______________________________________________________________________
b.
Which planet has the weakest gravity? Explain.
_____________________________________________________________________