Pendulum Painter: Explore Motion, Time & Patterns!
Introduction
Have you ever watched a playground swing move back and forth?
A swing moves forward, comes back, moves forward again, and keeps repeating this motion. This type of swinging motion can also be seen in a simple science tool called a pendulum.
A pendulum is an object hanging from a fixed point by a string or rod that can swing back and forth.
But today, we are not just going to watch a pendulum swing—we are going to turn it into an artist!
In this Pendulum Painter activity, we will hang a small cup filled with liquid paint from a string and allow it to swing over a sheet of paper. As the cup moves, the paint will flow onto the paper and create lines, curves, loops, and interesting patterns.
Now comes the exciting part!
We will make two or three pendulums using different lengths of string.
For example:
- Short string
- Medium string
- Long string
We will put the same amount of different color paint into identical cups and allow each cup to swing.
Then we will compare the artwork.
Our Big Question
What happens to the paint pattern when we change the length of the string?
Will a shorter string create a different pattern from a longer string?
Will the shorter pendulum swing faster?
Will the longer pendulum take more time to complete its swing?
Let’s explore, measure, observe, and discover!
Materials Required
To perform this experiment, you will need:
Main Materials
- 3 identical small cups
- 3 pieces of string with different lengths
- 3 different colors (red, blue and green) liquid paints.
- Large sheets of paper
- A sturdy support or frame
- Tape
- Scissors
- Ruler or measuring tape
- Stopwatch or timer
- Measuring cup or measuring spoon
Suggested String Lengths
You can use three different lengths, such as:
- Short string – 30 cm
- Medium string – 50 cm
- Long string – 70 cm
Paint
Use the same type of liquid paint for all cups.
For example:
- Cup 1 → 20 mL blue paint
- Cup 2 → 20 mL red paint
- Cup 3 → 20 mL green paint
You can use different colors for each cup if you want the final artwork to be easy to compare.
Before You Begin
This is a fun and simple activity, but children should take a few safety precautions.
Safety Instructions
- Perform the activity on a stable table or floor.
- Protect the working surface with newspaper or a plastic sheet.
- Use washable, child-safe liquid paints.
- Be careful when making a small hole in the cup.
- Ask an adult for help when using scissors or making holes.
- Make sure the pendulum support is strong and stable.
- Do not swing the cup near people or electronic devices.
- Clean up spilled paint immediately.
Target Age Group
This Pendulum Painter experiment is suitable for children aged approximately 7–12 years.
Ages 7–9
Children can observe:
- Which pendulum swings faster
- Which one swings slower
- How the paint creates different patterns
- How string length changes movement
Ages 10–12
Children can explore:
- Pendulum period
- Frequency
- Gravity
- Motion
- Measurement
- Variables
- Data collection
- Pattern formation
Learning Objectives
After completing this experiment, children will be able to:
- Understand what a pendulum is.
- Observe how string length affects pendulum motion.
- Measure the time taken by a pendulum.
- Compare short and long pendulums.
- Understand the idea of period and frequency.
- Observe how motion can create patterns.
- Record observations in a table.
- Identify independent, dependent, and controlled variables.
- Connect science with art and creativity.
What Is a Pendulum?
A pendulum is an object suspended from a fixed point that can swing back and forth.
A playground swing is a familiar example of a pendulum-like system.
In this experiment, instead of using a simple weight, we attach a small cup containing liquid paint to a string.
When the cup swings, the paint moves with it and flows onto the paper.
The result is a beautiful pattern created by the motion of the pendulum.
Step-by-Step Instructions
Step 1: Prepare the Strings
Take three pieces of string with different lengths.
String A-30 cm
String B-50 cm
String C-70 cm
Measure each string carefully using a ruler.
Write the lengths down before beginning the experiment.
Step 2: Prepare the Cups
Take three identical cups.
The cups should have:
- The same size
- The same shape
- Approximately the same weight
Label them:
- Cup A – Short Pendulum
- Cup B – Medium Pendulum
- Cup C – Long Pendulum
Using identical cups makes the experiment more accurate.
Step 3: Create a Small Opening
Make a small hole near the bottom of each cup.
The hole allows a small amount of paint to flow onto the paper while the cup swings.
The opening should not be too large.
Why?
If too much paint comes out at once, it may make a large puddle instead of creating a pattern.
Ask an adult to help with this step.
Step 4: Attach the Strings
Secure one string to each cup. Make sure the connection is strong enough to support the cup.
You should now have:
Short string + Cup A
Medium string + Cup B
Long string + Cup C
Step 5: Set Up the Pendulums
Start with the shortest string. Hang the cup from a stable support. In the same way, attach 2 other strings.
Check that:
- The cup can swing freely.
- The string does not get tangled.
- The cup does not hit the support.
- The paint can flow toward the paper.
Step 6: Prepare the Paper
Place a large sheet of paper underneath the pendulum.
Secure the paper using tape.
The paper will act as the canvas for your experiment.
Make sure there is enough space for the pendulum to swing and create a pattern.
Step 7: Add Equal Quantities of Paint
Measure 20ml of paint and pour into each cup.
Make sure the quantity is equal.
| Cup | String Length | Paint Quantity |
| A | 30 cm | 20 mL |
| B | 50 cm | 20 mL |
| C | 70 cm | 20 mL |
This is important because we want to investigate the effect of string length, not the amount of paint.
Step 8: Start the Short Pendulum
Move the cup slightly away from its resting position. Release it without pushing it.
Start your stopwatch.
Observe carefully.
Watch for:
- How quickly the cup swings
- How long each swing takes
- How far the paint travels
- What kind of pattern is created.
Step 9: Measure the Swinging Time
Instead of measuring just one swing, count 10 complete swings.
Record the total time.
For example:
10 swings = 12 seconds
Your result may be different.
Then calculate the approximate time for one swing:
12 ÷ 10 = 1.2 seconds
Step 10: Repeat With the Medium Pendulum
Now use the medium-length string.
Use:
- The same size cup
- The same amount of paint
- The same type of paint
- The same starting position
- The same paper setup
Release the cup without pushing.
Measure the time for 10 swings.
Observe the pattern.
Step 11: Repeat With the Long Pendulum
Finally, test the longest string.
Again:
- Add the same quantity of paint.
- Hang the cup securely.
- Use the same starting position.
- Release without pushing.
- Measure 10 swings.
- Observe the painting.
Observe the Paint Patterns
Now compare all the paintings.
You may see:
- Curved lines
- Waves
- Loops
- Spirals
- Overlapping lines
- Dots
- Large or small patterns
The pattern is a visual record of the pendulum’s movement.
Observation Table
This is an important part of the Pendulum Painter experiment.
Record your observations carefully.
| Pendulum | String Length | Paint Quantity | Time for 10 Swings | Approx. Time for 1 Swing | Pattern Size | Pattern Description |
| A – Short | 30 cm | 20 mL | ____ s | ____ s | ____ | __________ |
| B – Medium | 50 cm | 20 mL | ____ s | ____ s | ____ | __________ |
| C – Long | 70 cm | 20 mL | ____ s | ____ s | ____ | __________ |
Compare Your Results
After completing the experiment, compare the results.
Ask yourself:
1. Which pendulum completed 10 swings in the shortest time?
2. Which pendulum took the longest time?
3. Which pendulum swung faster?
4. Which pendulum swung more slowly?
5. Did the pattern change when the string length changed?
6. Which pendulum created the largest pattern?
7. Which pendulum created the smallest pattern?
8. Did your prediction match your results?
What’s Happening Here? – The Science Explained
1. Gravity
Gravity is the force that pulls objects toward Earth.
When you pull the pendulum away from its resting position and release it, gravity helps pull it back toward the center.
This causes the cup to swing.
2. Pendulum Length
The length of the string affects how quickly the pendulum swings.
In general:
Shorter string → Faster swing
Longer string → Slower swing
This is one of the most important observations in this experiment.
3. Pendulum Period
The period is the time required for one complete back-and-forth cycle.
For a simple pendulum, the approximate relationship is:
T = 2π√(L/g)
Where:
- T = period
- L = length of the pendulum
- g = acceleration due to gravity
You do not need to calculate the formula to understand the experiment.
Your stopwatch measurements allow you to observe the relationship.
4. Frequency
Frequency tells us how many complete cycles happen in a certain amount of time.
A shorter pendulum generally has:
Shorter period → Higher frequency
A longer pendulum generally has:
Longer period → Lower frequency
5. Paint Movement
As the cup swings, the liquid paint inside the cup also moves.
The paint flows through the small opening and lands on the paper.
Because the cup is moving continuously, the paint creates a changing path.
The result is a unique artwork.
The painting is essentially a record of the pendulum’s motion.
Why Does the Artwork Change?
When the string length changes, the pendulum’s motion changes.
A shorter pendulum generally oscillates more quickly.
A longer pendulum generally oscillates more slowly.
This changes how the cup travels over the paper while the paint is flowing.
As a result, the patterns can be different.
Identify the Variables
Understanding variables is an important part of scientific experiments.
Independent Variable
The thing we intentionally change: Length of the string
Dependent Variables
The things we measure or observe:
- Time taken for 10 swings
- Approximate period
- Pattern size
- Pattern shape
- Paint flow pattern
Controlled Variables
The things we keep the same:
- Cup size
- Paint quantity
- Type of paint
- Starting position
- Paper
- Support
- Number of swings
Make It a Fair Experiment
For a good scientific experiment, we should change only one major factor at a time.
In this experiment:
We change:
String length
We keep the same:
Cup + paint quantity + paint type + starting position + paper
This helps us understand whether the observed difference is related to the string length.
Bonus Experiment 1: Change the Starting Position
Use the same string length.
First release the pendulum from a small angle.
Then release it from a larger angle.
Compare the paintings.
Question:
How does the starting position affect the pattern?
Mathematics Connection
Suppose your experiment Pendulum Painter produces these results:
| String Length | Time for 10 Swings | Approx. Period |
| 30 cm | 11 s | 1.1 s |
| 50 cm | 14 s | 1.4 s |
| 70 cm | 17 s | 1.7 s |
The approximate period is calculated using:
Period = Total time ÷ Number of swings
For example:
11 ÷ 10 = 1.1 seconds
This allows us to compare the swinging time of different pendulums.
Your actual results may be different.
Real-World Connections
The science behind this simple Pendulum Painter experiment can be found in many real-world applications.
Pendulum Clocks
Pendulums have been used in clocks to create regular motion for timekeeping.
Metronomes
Musicians use pendulum-like systems to maintain a steady rhythm.
Engineering
Engineers study oscillations and vibrations when designing buildings, bridges, machines, and other structures.
Fluid Flow
Understanding how liquids move is important in many industries, including paint manufacturing, food processing, and engineering.
Final Challenge
Can you answer this question?
If we increase the length of the pendulum, what happens to the time taken for each swing and how does the paint pattern change?
Use your observation table and paintings as evidence for your answer.
Try to explain your answer using scientific words such as:
gravity, motion, pendulum, period, frequency, length, and liquid flow.
Conclusion
In this Pendulum Painter experiment, we transformed simple cups of paint into pendulum-powered paintbrushes.
By using two or three different string lengths while keeping the cup size, paint quantity, and other conditions the same, we investigated how pendulum length affects motion and the artwork produced.
We discovered that:
✔ Shorter pendulums generally swing faster.
✔ Longer pendulums generally swing more slowly.
✔ Pendulum length affects the period of motion.
✔ Gravity causes the pendulum to swing.
✔ Moving paint can create patterns that show the path of motion.
✔ Measuring and recording data helps us compare results.
✔ Science, mathematics, engineering, and art can work together.
The most exciting part?
The painting isn’t just artwork.
It is a visual record of physics in motion!
Frequently Asked Questions
1. Why does the shorter pendulum swing faster?
A shorter simple pendulum has a shorter period, so it completes each swing in less time than a longer pendulum.
2. Why does the longer pendulum swing more slowly?
As the pendulum length increases, its period increases. Therefore, it takes more time to complete each cycle.
3. Why should all the cups be the same size?
Using identical cups keeps the experiment fair and reduces the effect of differences in cup size or shape.
4. Why should we use the same quantity of paint?
The same quantity ensures that the amount of paint does not become another variable affecting the experiment.
5. Why do we measure 10 swings instead of just one?
Measuring several swings makes the timing more reliable and reduces the effect of small stopwatch errors.
6. Why does the paint create different patterns?
As the pendulum moves, the cup travels across the paper while the paint flows through the opening. The motion of the cup determines the path of the paint.
7. What scientific concepts are demonstrated in Pendulum Painter experiment?
This Pendulum Painter experiment demonstrates:
- Gravity
- Pendulum motion
- Period
- Frequency
- Energy
- Measurement
- Variables
- Data collection
- Liquid flow
