The Best Examples of Energy Conservation: Pendulum Projects for Science Fairs

Let’s skip the dry theory and jump straight into real setups you can build. All of these are examples of energy conservation: pendulum projects that show one big idea:

As a pendulum swings, gravitational potential energy at the top turns into kinetic energy at the bottom, then back again.

You don’t have to say it in textbook language at your science fair, but you do want to show it with measurements, graphs, and clear questions.

Below are several of the best examples you can adapt, combine, or scale up, depending on your grade level and how ambitious you feel.

Example of a classic pendulum energy conservation project

A great starting point is the single, simple pendulum: a weight on a string, swinging from a fixed point. This is the “lab rat” of examples of energy conservation: pendulum projects because it’s easy to control and measure.

You can:

• Hang a small metal washer or a nut from a piece of string taped to a door frame.
• Pull it back a measured distance (say, 4 inches), release, and time several swings.
• Repeat for different release heights.

What you’re showing:

• At the highest point, the bob has maximum gravitational potential energy (because it is highest above its lowest point).
• As it falls, that potential energy becomes kinetic energy; the pendulum moves fastest at the bottom.
• As it rises to the other side, kinetic energy turns back into potential energy.

If you want to connect to real physics, you can calculate the potential energy at the top using the height change and the bob’s mass. A solid reference for the basic equations of energy in motion is the Khan Academy physics section on work and energy (https://www.khanacademy.org/science/physics/work-and-energy), which is widely used in U.S. classrooms.

What to measure and graph:

• Measure the maximum height on each side for several swings.
• Track how that height slowly decreases over time.
• Graph swing number (1, 2, 3, etc.) versus maximum height.

Your story: Energy is not lost; it is transferred to the air (air resistance) and the support (friction at the top), eventually becoming thermal energy. That’s why the pendulum slowly stops.

Using phone sensors: modern examples of energy conservation with pendulums

If you want a 2024‑style upgrade, turn your phone into a physics sensor. Many free apps measure acceleration and angle using the phone’s built‑in sensors.

In this example of a modern pendulum project:

• Securely strap or tape an old smartphone to a sturdy pendulum bob (a small block or a 3D‑printed holder).
• Use a sensor app to record angle or acceleration as the pendulum swings.
• Export the data to a spreadsheet.

Now your examples of energy conservation: pendulum projects have real, time‑stamped data you can graph:

• Angle vs. time
• Speed vs. time (some apps can estimate this)
• Energy vs. time (you can calculate approximate potential and kinetic energy from the angle and speed)

You can compare:

• Small swings vs. large swings
• Short strings vs. long strings
• Different bob masses

Your story: Even as the shape of the motion changes slightly, the total mechanical energy (potential + kinetic) stays nearly constant from one instant to the next, then slowly leaks away to the environment. This is exactly the kind of behavior described in standard physics curricula, such as MIT OpenCourseWare’s intro physics materials (https://ocw.mit.edu/courses/physics/).

Best examples of multi‑pendulum energy conservation projects

Once you’ve mastered the single pendulum, you can create more dramatic examples of energy conservation: pendulum projects by linking pendulums together.

Coupled pendulums: energy passing back and forth

Imagine two pendulums hanging from the same horizontal string or bar, fairly close to each other. When you pull one back and release it, watch what happens:

• At first, only the first pendulum swings.
• Over time, its motion slows down.
• The second pendulum mysteriously starts swinging more.

You’ve just built a real example of energy transfer between pendulums. Energy moves from one pendulum to the other through the flexible support. This is a beautiful demonstration that total energy in the system is roughly conserved, but it is shared between different parts.

What you can measure:

• The amplitude (maximum angle) of each pendulum over time.
• How long it takes for most of the energy to move from one pendulum to the other and back.

Your story: This is a visible version of how energy can slosh around between different parts of a system, a topic that appears in many college‑level physics discussions of coupled oscillators.

Pendulum wave: a visual show of energy and timing

Another crowd‑pleaser is the “pendulum wave” setup. You hang several pendulums in a row, each with a slightly different length, so they have slightly different periods. When you release them all at once, the pattern of motion changes over time: sometimes they look like a wave, sometimes like random chaos, and then they return to the original pattern.

This is one of the best examples of how precise timing and energy conservation can create complex, eye‑catching patterns. You can find background on pendulum periods and timing relationships in university physics notes, such as those from the University of Colorado Boulder’s physics department (https://www.colorado.edu/physics/).

What to explain:

• Each pendulum individually still trades potential and kinetic energy back and forth.
• The wave patterns are not magic; they come from small differences in period.
• Total energy in each pendulum slowly decreases due to friction and air resistance, but the pattern itself is a result of math and timing.

Real examples: energy conservation with a pendulum and collisions

If you want to connect your pendulum project to real‑world safety topics, you can combine a pendulum with collisions. This opens the door to conversations about car crashes, sports helmets, and playground safety.

Pendulum crash test: measuring impact

Set up a pendulum that swings a small ball or block into a target:

• Use a clay block, foam pad, or even a soda can as the target.
• Mark the starting height of the pendulum.
• Measure the deformation (dent depth, clay imprint length, etc.) after each collision.

This gives you a real example of how energy is transferred during impact:

• The pendulum’s gravitational potential energy at the start becomes kinetic energy at the bottom.
• At impact, that kinetic energy is transferred to the target, deforming it and sometimes heating it slightly.

You can compare:

• Different target materials (foam, cardboard, clay, aluminum can).
• Different starting heights.

Your story: Softer materials spread out the impact, which is related to how bike helmets and car crumple zones protect people by absorbing energy. Organizations like the National Highway Traffic Safety Administration (https://www.nhtsa.gov) publish research and guidelines on impact safety, which you can cite in your background section.

Damping and friction: examples include air resistance and different surfaces

Not all examples of energy conservation: pendulum projects have to be flashy. Some of the most thoughtful ones focus on where the “missing” energy goes as the pendulum slows down.

Comparing air resistance

You can:

• Build two pendulums with identical strings and masses.
• Wrap one bob in a shape with more surface area (like adding cardboard fins) to increase air resistance.
• Release both from the same height and time how long it takes for each to come nearly to rest.

Your observations:

• The high‑drag pendulum loses its mechanical energy faster.
• That energy hasn’t vanished; it has been transferred to the air as heat and tiny air currents.

Comparing pivot friction

Or:

• Use different pivot setups: a smooth metal hook, a rough nail, a string over a rod.
• Keep the bob and string length the same.

You’ll see that some pivots let the pendulum swing longer. Here, more of the mechanical energy is being converted into heat at the pivot where friction acts.

Your story: These are everyday examples of energy conservation. They connect directly to real engineering problems, like designing efficient clock mechanisms or reducing energy loss in machinery.

Pendulum clocks: historical and modern examples of energy conservation

Pendulum clocks are classic real examples of energy conservation in everyday technology. For centuries, they kept time in homes, schools, and observatories.

How they fit your project:

• The pendulum itself constantly trades potential and kinetic energy.
• The clock’s mechanism gives small pushes (from a wound spring or descending weight) to replace the energy lost to friction and air resistance.

You can build a simple demonstration:

• Create a pendulum that swings freely and time how long it stays in motion.
• Add a gentle “kick” mechanism, like a small magnet or a finger tap at the bottom of the swing, to keep it going.

Your story: Without extra energy added, the pendulum slows and stops because energy is transferred to the environment. With carefully timed inputs, you can maintain nearly constant motion—exactly what a clock does.

This connects nicely to the broader law of conservation of energy, which is a cornerstone of modern physics and is highlighted in many educational resources from universities and science museums.

Turning these examples of energy conservation: pendulum projects into winning science fair entries

Having many examples of energy conservation: pendulum projects is great, but judges care about how clearly you ask and answer a question.

To sharpen your project:

Pick one main question. For example:

• How does release height affect the speed at the bottom of a pendulum’s swing?
• How does air resistance change the rate at which a pendulum loses energy?
• How does energy transfer between coupled pendulums over time?

Plan your variables.

• Independent variable: what you change (height, string length, bob shape, material, etc.).
• Dependent variable: what you measure (period, maximum height after each swing, time until stop, impact distance, etc.).
• Controlled variables: what you keep the same (mass, string type, room temperature as much as possible, measurement method).

Gather data the smart way.

• Time multiple swings and divide by the number of swings to reduce reaction‑time error.
• Use video (slow‑motion on a phone) to measure angles and speeds more accurately.
• Repeat each trial several times and average your results.

Explain energy in plain language.
Instead of memorizing formulas, be ready to say something like:

At the top of its swing, the pendulum has stored energy because gravity can pull it down. As it falls, that stored energy turns into motion energy. At the bottom, it’s moving fastest. Then it climbs up the other side, turning motion energy back into stored energy.

This simple explanation, paired with graphs and data, is often what makes your project stand out.

FAQ about examples of energy conservation: pendulum projects

What are some easy examples of energy conservation using a pendulum for beginners?

Easy examples of energy conservation: pendulum projects include a basic single pendulum where you measure how the height of the swing decreases over time, or a comparison of two pendulums with different string lengths to see how the period changes. Another beginner‑friendly example of a project is testing how different bob masses affect how long the pendulum swings before stopping (spoiler: mass doesn’t change the period, but it can affect how long it takes to slow down if friction is involved).

Can I use a pendulum project to talk about real‑world safety or engineering?

Yes. A pendulum impact setup is a strong real example of energy conservation in action. By swinging a pendulum into different materials, you can show how energy is transferred and absorbed during a collision. This connects directly to helmet design, car crash safety, and playground equipment testing, topics that agencies like NHTSA and various engineering departments study in depth.

Are pendulum projects still relevant in 2024–2025 science fairs?

Absolutely. Judges still appreciate pendulum projects because they are clear, measurable examples of physics principles. What’s changed is how you can collect and present data. Using phone sensors, free data‑logging apps, and simple spreadsheets lets you push a classic experiment into modern territory. Many current high‑school physics courses and online resources, including those from major universities, still use pendulums as standard examples of energy conservation.

How can I make my pendulum project look more advanced without expensive equipment?

You can:

• Add a second pendulum and study energy transfer.
• Use slow‑motion video to measure angles and speeds more accurately.
• Compare different damping methods (air resistance, pivot friction, different fluids if you submerge the bob).

These adjustments turn simple setups into richer examples of energy conservation: pendulum projects with deeper analysis.

Is a pendulum project okay for middle school, or is it only for high school?

Pendulum experiments scale nicely. For middle school, you might stick to timing swings and observing patterns. For high school, you can calculate approximate energies, model the motion, and compare your data to theoretical predictions. In both cases, pendulum setups remain some of the best examples of how to see energy conservation with your own eyes.

If you focus on a clear question, careful measurements, and a simple explanation of how energy moves and changes form, any of these examples of energy conservation: pendulum projects can turn into a strong, memorable science fair entry.