quest: understanding gravitational potential...

Quest: Understanding Gravitational Potential Energy ***

Learning Target:

-I can explain that gravitational potential energy changes in a system as the masses or

relative position(s) of objects are changed.

-I can identify and compare gravitational, elastic, chemical, electrical, and magnetic

potential energy.

-I can, given specific materials, plan and implement an experiment to determine the

relationship between the height/mass of a metal sphere and the amount of change it can

make to sand held in a container below.

The steam-powered robot crashes into a

nearby train station as you deliver the crippling

assault! You manage to secure Necrift at last

and tie his hands together with rope.

“You’ve stopped nothing!” Necrift rages.

“General Ohm will unleash the stored potential

energy in all things! Why do you think we have

wasted so much time capturing scientists?!”

“What potential energy?” you question.

“There exist many types of energy and many

of them are ‘stored’, waiting to be unleashed. I

will give you a hint about the first type of

potential energy. Look to the skies!” The

masked madman nudges his head behind you

where a fleet of enemy airships open bomb

doors. The tiny weapons begin falling over the

city. Each one sprouts a blossom of smoke and

fire! “Gravitational potential energy is working

against you, allowing these weapons to be

pulled by gravity to the streets!”

In the distance you see that a carnival complete with a roller coaster is hammered

hard by the falling explosives. Many of the weapons, however, are causing damage and

destruction even though they are not blowing up.

“All it takes sometimes is a good amount of gravitational potential energy to

cause destruction!” Necrift crows happily! “Not all of them have to explode for them to

do their dirty work. Just think about meteors! The extinction of hundreds of species on

your home of Earth was caused because gravity pulled a hunk of rock into the surface!”

You call out to Da Vinci and the Wright Brothers, “Is the Inertia able to fly yet?”

“Not yet. They are still working on her.” Da Vinci answers. “Hurry to Nikola

Tesla. Help him use his inventions to take out the enemy fleet. I will interrogate our

masked friend here.”

Da Vinci hands you a map and you and your friends rush closer to the carnival

that looks like Coney Island to search for the mysterious Nikola Tesla.

Objective: In this activity, you will be changing the height of a small sphere and the

mass of the sphere to determine their relationship with gravitational potential energy.

You will determine what affects the strength of gravitational potential energy, (GPE).


Goal 1: Collect data to determine how increasing the height between an object and

the surface affects its GPE

Goal 2: Collect data to determine how increasing the mass of a falling object affects

its GPE

Materials: Steel Ball, Glass Ball, Ruler, Sand

Data Tables- NOTE: USE THE INCLUDED DATA SET AT THE END TO FILL

OUT YOUR DATA TABLES!

Title: Changing the Height of the Steel Ball (Mass of 14 g)

Drop Height

(cm)

Crater

Diameter Trial

1 (cm)

Crater

Diameter Trial

2 (cm)

Crater

Diameter Trial

3 (cm)

Crater

Diameter

Average (cm)

10 cm

25 cm

50 cm

Title: Changing the Height of the Glass Ball (Mass of 5 g)

Drop Height

(cm)

Crater

Diameter Trial

1 (cm)

Crater

Diameter Trial

2 (cm)

Crater

Diameter Trial

3 (cm)

Crater

Diameter

Average (cm)

10 cm

25 cm

50 cm


Analysis: The strength of the gravitational potential energy is seen in the size of the

impact crater. The larger the crater, the more energy the sphere had to begin with due to

gravity. Use your data from the trials to answer the following in complete sentences.

1. How does increasing the height before impact affect the amount of gravitational

potential energy?

2. How does increasing the mass of the impacting object affect the amount of

gravitational potential energy? For this question, compare the steel ball and marble at the

same height and determine which had a more significant impact crater.

3. Could the strength of gravity between objects have an influence on the amount of

gravitational potential energy as well? (Think of what things can change the strength of a

gravitational field force)

4. One student claims the following regarding how mass, height, and the acceleration due

to gravity are related to gravitational potential energy. He states that as mass increased,

GPE increased. He states that as height increased, GPE increased. He states that as the

strength of gravity increases, GPE would increase. He then writes a formula based on

these relationships: GPE = (mass) x (height) x (acceleration from gravity)

Does your data support his claims? Why or why not?


5. Calculate the gravitational potential energy, in Joules (J), for the glass ball using the

equation:

GPE = m*g*h Note: We will be calculating this based on the 50 cm drop.

g = 9.8 m/s2

-You must convert the mass of the ball to kilograms.

-You must convert the height of the drop to meters.

Show your work here and circle your answer with proper units.

6. 5. Calculate the gravitational potential energy, in Joules (J), for the steel ball using the

equation:

GPE = m*g*h Note: We will be calculating this based on the 50 cm drop.

g = 9.8 m/s2

-You must convert the mass of the ball to kilograms.

-You must convert the height of the drop to meters.

Show your work here and circle your answer with proper units.

7. Do your calculations of gravitational potential energy for the glass ball and steel ball

match your impact crater size data? Explain using your 50 cm drop height impact crater

data as evidence.


DATA SET- Use this data that your teacher collected to complete your data tables and

analysis questions.

The data was collected by dropping a glass ball and steel

ball from the stated height (10 cm, 25 cm, and 50 cm)

above a sandy surface. Each ball was dropped for three

trials. The crater that was left by the impact was

photographed beside a ruler. Use the ruler to measure

the crater diameter in centimeters. I have provided a

white circle to indicate the highest ridge for each crater.

This will help you measure to the nearest tenth for your

crater diameter measurements.

Record these crater diameters in the proper location of

your data tables. You will then calculate the average

crater diameter for each height drop trial.

This is a nice introduction to gravitational potential

energy because the crater that is left behind is created by

the energy that the glass ball and steel ball had gained

when they were lifted above the surface. All of the

potential energy is converted into kinetic energy as it

falls, and that kinetic energy is displayed by the crater

imprint. The larger the crater diameter, the more energy

the sphere had to start off with. Use this as a guide when

you complete the analysis questions!

quest: understanding gravitational potential...

Documents