Names: June 4, 2010

Seventh Grade

PLAYGROUND PHYSICS

PURPOSE: To investigate the physics of playground equipment.

BACKGROUND INFORMATION:

Playground equipment operates according to the laws of physics. Pay particular attention to the followingtopics:

  1. Newton’s Laws of Motion

First: An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Second: FORCE = MASS times ACCELERATION

Third: For every action there is an equal and opposite re-action.

  1. Momentum: the mass of an object times the speed the object is moving
  2. Rotational Inertia: if an object is spinning, it has a tendency to keep spinning until a force acts upon it
  3. Mass of an object: the measure of how much substance it has.
  4. Acceleration: a change in speed or direction of motion.
  5. Force: a push or pull that causes an object with mass to change velocity or speed; the capacity to do work or cause physical change; any influence that causes a free body to undergo an acceleration: examples of forces: gravity, friction,
  6. Pendulum: A body suspended from a fixed support so that it swings freely back and forth under the influence of gravity

MATERIALS AND EQUIPMENT:

Swing SlideJungle GymMerry-go-round

Stopwatch CalculatorMetric tape measure Tennis ball

Your weight: ______

MERRY-GO-ROUND (MGR):

1. Measure the radius from the outer rim to the center. Record. ______m

2. Calculate the circumference of the circle. ______m

4. Have a person sit on the outer rim and another at the midway point. Get the MGR moving (assume aconstant velocity). Measure the time for three complete turns. Calculate average speed at each placewhere a person is sitting.

5. Who experiences the faster ride?

2. While the Merry Go Round is in motion is the speed affected when people move toward the center then out toward the edge?

6. Have two team members sit on opposite sides of the MGR. Push to get the MGR moving. Have oneteam member toss a tennis ball to the person on the opposite side while the MGR is in motion. Do youexperience any difficulties? ______Explain what they are.


Explain the cause of any differences in the observed path of the tennis ball.

8. Have two partners stand on either side of the MGR. Get the MGR in motion and have the two team members slowly lean out as far from the MGR as possible. Note any changes in the speed of the MGR.

9. While the MGR is still in motion, have the two partners pull slowly in toward the center of the MGR. Note any changes in the speed of the MGR.

10. Explain the changes when people move in and out of the MGR while it is in motion. (What affects the speed?)

11. Did the people notice any difficulty in pulling back from an extended position while the MGR was in motion? What force opposed the inward pull you were exerting?

Do any of Newton’s Laws apply to the motions that you observed? Explain.

Finally, write a brief paragraph about what you learned in this experiment

Names: Names: June 4, 2010

Seventh Grade

PLAYGROUND PHYSICS

PURPOSE: To investigate the physics of playground equipment.

BACKGROUND INFORMATION:

Playground equipment operates according to the laws of physics. Pay particular attention to the following topics:

  1. Newton’s Laws of Motion

First: An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Second: FORCE = MASS times ACCELERATION

Third: For every action there is an equal and opposite re-action.

  1. Momentum: the mass of an object times the speed the object is moving
  2. Rotational Inertia: if an object is spinning, it has a tendency to keep spinning until a force acts upon it
  3. Mass of an object: the measure of how much substance it has.
  4. Acceleration: a change in speed or direction of motion.
  5. Force: a push or pull that causes an object with mass to change velocity or speed; the capacity to do work or cause physical change; any influence that causes a free body to undergo an acceleration: examples of forces: gravity, friction,
  6. Pendulum: A body suspended from a fixed support so that it swings freely back and forth under the influence of gravity

MATERIALS AND EQUIPMENT:

Swing SlideJungle GymMerry-go-round

Stopwatch CalculatorMetric tape measure Tennis ball

Your weight: ______

SWINGS:

Make your own hypothesis about what controls how the swing moves. Answer these questions BEFORE getting on the swings.

1. What determines how long it takes a swing to go back, forward, and back again? Does your weight make a difference? Is the length of the string important? Does gravity play a role?

2. When you swing higher does your speed change?

3. When you swing higher does the period of the pendulum change?

4. If you want to swing as fast as you can, which swing would you pick: a swing with a short chain, a swing with a long chain, a swing with a heavy seat, or a swing with a light seat?

Why?

5. How does a swing really work? What allows it to move back and forth?

1. Have one partner get on the swing while another watches. Gets the swing moving without help from anyone else. a) What do you have to do (mechanically) to get the swing in motion?

b) Use physics to explain how your body motion operates the swing. (What produces the force?)

4. Measure the length of the chain (the length of a pendulum) from the top of the chain to the bottom of theswing seat. ______m

5. Get the swing going, and then try to remain as upright as possible to avoid affecting the swing. Time 5 complete swings (over and back is one swing). Determine the time for one swing (called a period: The period of a pendulum is the amount of time it takes to complete one full swing, back and forth.). Repeat with a heavier mass.

For the table below, time 5 back and forth movements (oscillations) of the swing with stop watch. Divide that time by 5 to get the period of one oscillation. Why should we time 5 periods instead of just one?

• What properties of your pendulum affect the period? Mass, length, speed, none of these, or all of these?

• How did your hypothesis work? Swing sets aren’t the only pendulums around. A yo-yo can be a pendulum, too. Can you think of any experiments you might like to try with a yo-yo? In what ways could your experiments be different than what you could do on a swing?

Now that the experiment is over, will you change your answers to the questions below?

1. What determines how long it takes a swing to go back, forward, and back again? Does your weight make a difference? Is the length of the string important? Does gravity play a role?

2. When you swing higher does your speed change?

3. When you swing higher does the period of the pendulum change?

4. If you want to swing as fast as you can, which swing would you pick: a swing with a short chain, a swing with a long chain, a swing with a heavy seat, or a swing with a light seat?

Why?

5. How does a swing really work? What allows it to move back and forth?

Do any of Newton’s Laws apply to the motions that you observed? Explain.

Finally, write a brief paragraph about what you learned in this experiment

Names: Names: June 4, 2010

Seventh Grade

PLAYGROUND PHYSICS

PURPOSE: To investigate the physics of playground equipment.

BACKGROUND INFORMATION:

Playground equipment operates according to the laws of physics. Pay particular attention to the following topics:

  1. Newton’s Laws of Motion

First: An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Second: FORCE = MASS times ACCELERATION

Third: For every action there is an equal and opposite re-action.

  1. Momentum: the mass of an object times the speed the object is moving
  2. Rotational Inertia: if an object is spinning, it has a tendency to keep spinning until a force acts upon it
  3. Mass of an object: the measure of how much substance it has.
  4. Acceleration: a change in speed or direction of motion.
  5. Force: a push or pull that causes an object with mass to change velocity or speed; the capacity to do work or cause physical change; any influence that causes a free body to undergo an acceleration: examples of forces: gravity, friction,
  6. Pendulum: A body suspended from a fixed support so that it swings freely back and forth under the influence of gravity

MATERIALS AND EQUIPMENT:

Swing SlideJungle GymMerry-go-round

Stopwatch CalculatorMetric tape measure Tennis ball

Your weight: ______

Slides:

Slide down the slide as you usually do and notice how fast and easily you slide. What do you think will happen if you changed what you are sliding on?
Try different materials below and enter the time it takes to get to the bottom:

Item / Trial one time / Trial two time / Average
cardboard
Paper bag / .
Plastic
Towel

Which material goes the fastest?

Which material goes the slowest?

Why do you think this happens?

Does friction prevent you from moving down a slide without a push?
.4. Should you be able to slide without pushing?

5. Have a partner slide down the slide. Is it necessary to use a pushing force, or does gravity providesufficient force?

1.) First, you need to perform an experiment to test the prediction that: the less body contact there is with a slide (as in a smaller surface area rather than a larger), the faster the velocity of the slider will be.

2.) In order to complete this, you first need to measure the height of the slide and record that result on your data table.

3.) Next, you need to calculate 3 trials for the time it takes a slider to go down the slide both sitting and laying down. Record these results on a data table and calculate the average time for each. This average value will be used to calculate the velocities for each scenario.

4.) To calculate the velocity, you would use the equation: change in position / change in time. In other words, the height of the slide, divided by the average time it took to slide down either sitting or lying down (record the resulting velocities on your data table).

Hypothesis 1 – The less body contact made with the slide, the less the velocity.

Sitting up / Trial one / Trial two / Trial three / Average
Height (meters)
Time (seconds) / .
Velocity (m/s)
Laying down / Trial one / Trial two / Trial three / Average
Height (meters)
Time (seconds)
Velocity (m/s)

9.) The last experiment for the slide that you have to perform will be to test the prediction that: momentum will be greater when pushed down the slide rather than sliding by yourself. (Note: the sliding by yourself velocity values can be obtained from the data table of the first experiment, the sitting down values).

10.) To calculate the pushed values, you need to first record the mass of the slider on your data table. Next, you need to perform three trials timing the amount of time it takes for the slider to reach the bottom of the slide being pushed, and record these results on your data table.

Hypothesis 2 – Time to get down the slide will differ if pushed by someone rather than sliding yourself

Sitting up / Trial one / Trial two / Trial three / Average
Height (meters)
Time (seconds) / .
Velocity (m/s)

Do any of Newton’s Laws apply to the motions that you observed? Explain.

Finally, write a brief paragraph about what you learned in this experiment

Names: June 4, 2010

Seventh Grade

PLAYGROUND PHYSICS

PURPOSE: To investigate the physics of playground equipment.

BACKGROUND INFORMATION:

Playground equipment operates according to the laws of physics. Pay particular attention to the following topics:

  1. Newton’s Laws of Motion
  2. First: An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
  3. Second: FORCE = MASS times ACCELERATION
  4. Third: For every action there is an equal and opposite re-action.
  5. Momentum: the mass of an object times the speed the object is moving
  6. Rotational Inertia: if an object is spinning, it has a tendency to keep spinning until a force acts upon it
  7. Mass of an object: the measure of how much substance it has.
  8. Acceleration: a change in speed or direction of motion.
  9. Force: a push or pull that causes an object with mass to change velocity or speed; the capacity to do work or cause physical change; any influence that causes a free body to undergo an acceleration: examples of forces: gravity, friction,
  10. Pendulum: A body suspended from a fixed support so that it swings freely back and forth under the influence of gravity

MATERIALS AND EQUIPMENT:

Swing SlideJungle GymMerry-go-round

Stopwatch CalculatorMetric tape measure Tennis ball

Your weight: ______

MONKEY BARS (MB):

Draw the monkey bars as viewed from above, in front and the side

Above / Front / Side

Are the monkey bars solid or hollow?

Explain how you tested to find out if the bar was hollow.

Which material are the monkey bars made from?

Are the monkey bars painted?Why or why not?

Fill in the table below with the measurements requested:

How high is the bar from the ground ? (cm or mm?)How wide one single bar?

What is the distance between each bar?What is the diameter of the bar?

Height / Width / Distance / Diameter
Measured value

Find 4 different ways of moving across the monkey bars and draw them below

One / Two / Three / Four
Time / Time / Time / Time

Next, each person in the group chooses one of the different ways to move along the bar. Time how long it takes each of you in turn to get across moving as fast as you can in the way you have chosen. Fill in the time in the above table.

Next using the fastest way, each of you in turn move across the bars and have someone time how fast you go

Name
Time

Start at one end of the monkey bars and go as fast as you can to the other side. STOP IMMEDIATELY when you reach the last rung. Can you do it?

Why or why not?

Now, start the stop watch and all hang by both hands. Who holds on the longest? Name:

This time start the watch and hang on by one hand. Who holds on the longest? Name:

Name / Time 1 hand / Time 2 hands

Analyzing

Does the height of a person make a difference to how long they take to move across the monkey bars?

Explain your answer.

Why can’t you hang forever from the bars?

Which of these would make a difference and why;

Longer arms

The height of the bars above the ground

Distance between the bars

Grease on the bars

Does how you move across the monkey bars make a difference to the time you take to get across. Explain your answer.

When you hang from a monkey bar, what is the name of the force which pulls down on your body?

Why are monkey bars made from steel and not from glass or plastic?

Do any of Newton’s Laws apply to the motions that you observed? Explain.

Finally, write a brief paragraph about what you learned in this experiment