Animate Carbon and Nitrogen Cycles

Create a self-playing video that compares carbon and nitrogen cycles.

Introduction

30 Second Summary

The carbon cycle can look almost identical to the nitrogen cycle on a page full of arrows. Their most important gateway difference disappears when both become vocabulary lists.

In this project, you will build a short, captioned Keynote animation that follows one carbon atom and one nitrogen atom through Earth's major reservoirs. The exported movie ends with a comparison of their gateways, connections, and major human disruptions.

What You'll Build

Press play to watch a carbon atom complete its journey before a nitrogen atom hits a blocked shortcut that only microbes can unlock.

By the end of this project, you'll have:

A complete carbon pathway that you can follow through air, organisms, soil, ocean, and long-term storage. The moving atom makes photosynthesis, respiration, decomposition, ocean exchange, burial, and combustion visible.
A failed nitrogen shortcut that visibly stops atmospheric N2 before it enters a plant. The corrected route then reveals fixation, nitrification, assimilation, ammonification, and denitrification in order.
A self-playing .mov with readable captions across all five slides. The final scene compares each cycle's main gateway plus its major human disruption.
Secret Mission: Add a final plant-growth overlay that shows carbon entering through photosynthesis. Usable nitrogen enters through assimilation before both return through decomposition.

Are there any prerequisites?

A Mac with Keynote installed is all you need. Basic familiarity with adding text or shapes is enough because the guide includes every scientific detail plus each required Keynote action.

Before We Start

Before any hands-on work begins, this is your moment to commit to one clear visual story about two complex cycles. Naming the difference you want to remember gives the whole video a focus.

Set Up the Keynote Storyboard

Version differences can move controls in Keynote. A feature check now keeps your storyboard from stalling after the science scenes are built.

You will create a five-slide shell for the full video. You will also test one title animation before building either cycle.

In this step, get ready to:

Confirm the required Keynote features.
Create the five-slide storyboard.
Test an animated title slide.

Check the Keynote controls

A feature check turns version uncertainty into a short checklist. Once each required control is visible, the rest of the project can use one consistent workflow.

Use your Mac's app search to find Keynote.
Launch Keynote from the search result.
Click Keynote in the macOS menu bar.
Choose About Keynote.
Record the installed version: your Keynote version.
Close the version window.

You now have a precise version reference if a control looks different later.

Click File in the macOS menu bar.
Choose New.
Select a simple theme.
Click Create.

You should see a title slide inside an editable presentation window.

Confirm the toolbar contains Shapes.
Select the title placeholder.
Click Animate.
Confirm the Build In tab is available.
Confirm you can see Add an Effect plus Preview.

The animation controls are in place. One final check confirms that this version can export the finished presentation as a movie.

Click File in the macOS menu bar.
Point to Export To.
Confirm Movie is listed.

Missing a Keynote control?

Click once on the open slide before checking the toolbar again.
Select the title placeholder before checking the animation controls.

Help me locate the required controls in my version of Keynote.

Create the five-slide storyboard

Each slide gives one part of the story a fixed home. The blank cycle slides become visual planning spaces in later steps.

Double-click the title placeholder on slide 1.
Enter Two Atoms, Two Journeys.
Select slide 1 in the slide navigator.
Press Return four times to add four slides.

You should see five slide thumbnails in the slide navigator.

Set slide 2's title to The Carbon Journey.
Set slide 3's title to Why Nitrogen Is Different.

The first three thumbnails should now show the opening title plus the two journey setup titles.

Set slide 4's title to The Nitrogen Journey.
Set slide 5's title to Same Planet, Different Gateways.

The five thumbnails should now display the full title sequence in order.

Slide order looks wrong?

Drag each thumbnail up or down until its position matches the five-title order above.
Check every title for missing words before continuing.

Help me correct my Keynote storyboard order.

Finish the animated title slide

The two circles introduce the atoms that the video follows. Their contrasting colors keep carbon and nitrogen visually distinct from the opening frame.

Select slide 1 in the slide navigator.
Click Shapes in the toolbar.
Choose a circle.
Double-click the circle.
Enter C.
Choose a fill color from the right sidebar.

The first atom marker should now appear beside the title.

Press Command+D to duplicate the selected circle.
Replace the duplicate's label with N.
Choose a contrasting fill color for the second circle.

Your title slide now introduces both atom journeys before the first cycle begins.

Select the title text.
Click Animate.
Choose the Build In tab.
Click Add an Effect.
Select one build effect for the title.

Before you click Preview, how do you expect the title to enter the slide?

Click Preview to test the effect.

You should see the title visibly animate onto the slide. That proves the Build In workflow is ready for the cycle scenes.

Title does not animate?

Select the title itself before opening Animate again.
Check that an effect appears under Build In.

Help me fix the title animation in Keynote.

Click File in the macOS menu bar.
Choose Save.
Enter two-atoms-two-journeys.key in the Save As field.
Choose a location from the Where menu.
Click Save.
Confirm the presentation name is two-atoms-two-journeys.key.

That's the setup complete. Your saved presentation now holds the tested visual framework for both journeys.

✔️ Awesome, I've got everything!

Great. Keep Keynote open with the title slide selected for the next step.

ⓧ I'd like to double check the full storyboard

Compare your saved presentation with this complete storyboard state:

The presentation is saved as two-atoms-two-journeys.key.
Slide 1 is titled Two Atoms, Two Journeys.
Slide 1 contains colored circles labeled C plus N.
Slide 1's title has a Build In effect tested with Preview.
Slide 2 is a blank storyboard slide titled The Carbon Journey.
Slide 3 is a blank storyboard slide titled Why Nitrogen Is Different.
Slide 4 is a blank storyboard slide titled The Nitrogen Journey.
Slide 5 is a blank storyboard slide titled Same Planet, Different Gateways.

Your five-slide storyboard is saved. Next, you will turn The Carbon Journey into the first working cycle animation.

Animate the Carbon Journey

Your Keynote storyboard already holds the five scenes for your comparison. Now the carbon slide needs to become the first complete scientific scene.

A working carbon cycle gives you an early version of the final video. Its apparent simplicity creates the pattern that the nitrogen scene challenges next.

In this step, get ready to:

Build the six carbon reservoirs.
Connect the reservoirs with seven labeled carbon fluxes.
Sequence the build effects for a readable preview.

Build the carbon reservoirs

Reservoirs are places where carbon is stored. Fluxes are processes that move carbon between them.

Select the The Carbon Journey slide in the slide navigator.
Use Shapes in the toolbar to add six matching shapes.
Label the first shape Atmosphere: carbon dioxide.
Label the second shape Plants.
Label the third shape Animals.
Label the fourth shape Soil and decomposers.
Label the fifth shape Ocean.
Label the sixth shape Rocks and fossil fuels.

Plan the visual hierarchy

The central biological loop runs through the atmosphere, plants, animals, and soil. Keeping those reservoirs near one another makes the short-term pathway easy to follow.

The ocean and rock reservoirs form a side branch. Extra space around that branch prevents long routes from crossing the main loop.

Move Atmosphere: carbon dioxide to the top of the slide.
Position Plants below the atmosphere on the left.
Position Animals below the atmosphere on the right.
Place Soil and decomposers beneath the living reservoirs.
Place Ocean near one side of the slide.
Place Rocks and fossil fuels beneath the ocean.

You should see four reservoirs forming a central loop. The ocean and long-term storage reservoirs should have their own clear branch.

Connect the carbon pathways

Connection lines turn the reservoirs into a model of carbon movement. The lines stay attached when you reposition a shape.

Use Shapes to add a connection line from Atmosphere: carbon dioxide to Plants.
Set the line endpoint at Plants to an arrow in the Style tab.
Add a text box labeled photosynthesis beside the line.
Create an arrow-ended connection line from Plants to Animals.
Add the label feeding beside that line.
Create an arrow-ended connection line from Animals to Soil and decomposers.
Add the label decomposition beside that line.

You can now follow carbon from the atmosphere into plants. The pathway continues through animals into soil.

Create an arrow-ended connection line from Soil and decomposers back to Atmosphere: carbon dioxide.
Add the label respiration beside that line.
Create a connection line with arrows at both ends between Atmosphere: carbon dioxide and Ocean.
Add the label ocean exchange beside that line.
Create an arrow-ended connection line from Ocean to Rocks and fossil fuels.
Add the label burial beside that line.
Create an arrow-ended connection line from Rocks and fossil fuels back to Atmosphere: carbon dioxide.
Add the label combustion beside that line.

What Do These Routes Mean?

The photosynthesis route moves carbon dioxide from the atmosphere into plants.
The feeding route transfers plant carbon into animals.
The decomposition route moves organic carbon into soil.
The respiration route returns carbon dioxide to the atmosphere.
The ocean exchange route moves carbon in both directions between surface water and the atmosphere.
The burial route moves some ocean carbon into long-term storage.
The combustion route sends stored carbon back into the atmosphere.

Reposition any connection line that crosses an unrelated reservoir.
Move each process label beside its matching line.

You should now be able to follow the central biological loop without losing the ocean and geological branch.

Sequence and preview the animation

Build effects control when each part of the pathway appears. The order turns the diagram into a journey instead of revealing every route at once.

Apply a simple effect to Atmosphere: carbon dioxide by using Animate, Build In, and Add an Effect.

Before you preview this first build, which reservoir do you expect to appear?

Click Preview.

You should see the atmosphere reservoir animate onto the carbon slide.

Apply a Build In effect to each remaining biological reservoir.
Apply a Build In effect to each biological route line with its label.
Arrange the biological builds in this order: Atmosphere: carbon dioxide, photosynthesis, Plants, feeding, Animals, decomposition, Soil and decomposers, and respiration.

Before you preview the loop, which process should bring carbon back toward the atmosphere?

Click Preview.

You should see the biological pathway build from atmospheric carbon dioxide through living organisms. The loop should finish with carbon returning toward the atmosphere.

Apply Build In effects to the ocean and geological branch.
Place the branch builds after the biological loop in the order Ocean, ocean exchange, burial, Rocks and fossil fuels, and combustion.

Before you preview the whole scene, which branch do you expect to appear after the biological loop?

Click Preview.

You should see the biological loop first. The ocean and geological branch should follow it.

Move any crowded process label into open space.
Save two-atoms-two-journeys.key.

Before the final preview, can you trace every arrow without guessing which label belongs to it?

Click Preview again.

You should see all six labeled reservoirs build into a readable cycle. The seven process routes should remain clear from the first build to the last.

That is your first complete scientific scene working. Carbon now moves through air, life, soil, ocean, and long-term storage in a visible sequence.

Does the Preview Feel Out of Order?

Move the ocean and geological builds after the biological loop.
Place each route label immediately after its matching connection line if they appear separately.
Check that each arrow endpoint points toward its destination reservoir.

Ask for help to fix the carbon animation order.

Your carbon pathway now provides the visual pattern for the comparison. Next, you will test whether nitrogen can follow the same route into a plant.

Block the Nitrogen Shortcut

Your Keynote carbon cycle animation now traces a complete journey through its major reservoirs. Its photosynthesis arrow gives carbon a visible route from the atmosphere into plants.

The question is whether the nitrogen cycle can copy that direct atmosphere-to-plant pattern. You will test the shortcut before the slide explains its scientific limit.

In this step, get ready to:

Model a direct route from atmospheric nitrogen into a plant.
Preview the claim made by the unblocked route.
Turn the attempted route into a clear scientific explanation.

Build the carbon-style shortcut

A connection line acts as a claim about movement between reservoirs. This trial uses the same visual grammar as the carbon slide.

Switch back to the blank slide titled Why Nitrogen Is Different.
Use the shape control in Keynote's toolbar to add a shape on the left side of the slide.
Label the left shape Atmospheric N2.
Add a second shape on the right side of the slide.
Label the right shape Plant.
Use Keynote's toolbar to add a connection line directly between the two shapes.
In the Style tab, add an arrow endpoint at the Plant end of the line.

What Does the Arrow Test?

The line presents the start point and end point as one uninterrupted route. Previewing it now lets you judge that claim before the slide explains the science.

Select the direct arrow.
Select the Animate sidebar.
Choose the Build In tab.
Click Add an Effect.
Select a simple appearance effect from the menu.

Before you click Preview, do you think this route communicates a valid gateway like photosynthesis?

Click Preview to test the direct route.

You will see the direct arrow appear from Atmospheric N2 to Plant. The animation gives the viewer no required transformation between them.

You found the model's weak spot: the copied route makes atmospheric nitrogen look directly available to plants.

Add the scientific stop message

Atmospheric N2 is unusable by plants and most algae. A stop symbol makes this constraint visible at the exact point where the shortcut fails.

Use the shape control in Keynote's toolbar to add a stop symbol.
Position the stop symbol over the center of the direct arrow.
Change the stop symbol to a color that contrasts with the arrow.
Add a text box beneath the direct arrow.
Enter Most plants cannot use atmospheric N2 directly.
Position the caption close to the stop symbol.
Adjust the caption size until it remains readable without covering either reservoir shape.

Why Block the Arrow Directly?

Placing the symbol on the arrow ties the explanation to the failed route. The viewer can immediately see which movement the caption rejects.

Reveal the shortcut before the block

Build order controls the logic of this scene. The attempted route needs its own moment before the stop message changes the viewer's interpretation.

Animation order can be fiddly because separate objects may receive separate builds. Treat the stop symbol and caption as one message while arranging their timing.

Apply a Build In effect to the stop symbol through Add an Effect.
Apply a Build In effect to the caption through Add an Effect.
Place the direct arrow first in the animation order controls.
Place the stop symbol after the direct arrow.
Set the caption to appear with the stop symbol.

Before you click Preview, which claim should the viewer see first?

Click Preview to test the complete sequence.

You will see the direct arrow build first. The stop symbol and caption then cover the attempted route so the journey ends at the warning.

Stop Message Appearing Too Early?

Select the direct arrow in the animation order controls.
Move the direct arrow before the stop symbol.
Set the caption to appear with the stop symbol.

Ask for help if the build sequence still reveals the objects in the wrong order: help me fix my Keynote animation order.

Save your changes to two-atoms-two-journeys.key.

That is the hard part complete: your slide now shows a tempting shortcut before rejecting it with the correct nitrogen fact.

The failed shortcut now has a visible boundary. Next, you will build the complete route that moves nitrogen through living systems.

Build the Microbe-Powered Nitrogen Cycle

Your blocked nitrogen shortcut now makes the problem visible in your Keynote story. The next scene needs to show the microbial route that solves it.

You will build the complete nitrogen loop. You will also add a compact comparison before rehearsing all five slides.

In this step, get ready to:

Build the complete microbe-powered nitrogen pathway.
Compare shared reservoirs. Explain the different gateways and human impacts.
Animate the pathways. Rehearse all five slides.

Build the nitrogen pathway

The failed arrow identified a chemical access problem. Most plants need usable nitrogen forms produced through microbial transformations.

Eight shapes can feel crowded on one slide. A broad loop leaves room for the return pathways.

How Does the Nitrogen Loop Work?

Nitrogen fixation is the microbial gateway that converts atmospheric N2 into ammonium.
Nitrification converts NH4+ into NO2-. It then converts NO2- into NO3-.
Assimilation moves nitrate into plant material.
Ammonification returns nitrogen from organic material to ammonium.
Denitrification returns nitrate to atmospheric N2.

Switch back to the blank slide titled The Nitrogen Journey.
Use the shapes control in the Keynote toolbar to add eight shapes.
Label the shapes Atmospheric N2, Nitrogen-fixing microbes, Ammonium NH4+, Nitrite NO2-, Nitrate NO3-, Plants, Animals, and Decomposers.
Arrange Atmospheric N2 at the top of a broad loop.
Arrange the microbe shape and the three chemical forms across the middle in pathway order.
Arrange Plants, Animals, and Decomposers along the bottom.

You should now see the atmosphere above a clear chemical pathway. The living part of the cycle should form a lower return loop.

Use arrow-ended connection lines for every pathway.
Connect Atmospheric N2 to Nitrogen-fixing microbes.
Connect Nitrogen-fixing microbes to Ammonium NH4+ with an arrow labeled fixation.
Connect Ammonium NH4+ to Nitrite NO2- with an arrow labeled nitrification.
Connect Nitrite NO2- to Nitrate NO3- with an arrow labeled nitrification.
Connect Nitrate NO3- to Plants with an arrow labeled assimilation.
Trace the pathway from atmospheric nitrogen to the plant.

You should be able to follow N2 through microbial processing before it reaches the plant.

Connect Plants to Animals with an arrow.
Connect Plants to Decomposers with an arrow.
Connect Animals to Decomposers with an arrow.
Connect Decomposers to Ammonium NH4+ with an arrow labeled ammonification.
Connect Nitrate NO3- to Atmospheric N2 with an arrow labeled denitrification.
Adjust any overlapping lines or process labels.

That is the bottleneck solved. Your nitrogen slide now makes microbes the gateway to usable forms.

Connections Moving Unexpectedly?

If a line crosses the wrong shape, move its endpoint to the intended shape. Keep each process label beside its own arrow.

help me untangle my Keynote nitrogen-cycle connections.

Compare the two cycles

A strong comparison separates the features both cycles share from the gateways that make them different. It also links each cycle to a visible environmental disruption.

Why Do These Impacts Matter?

Fossil-fuel burning rapidly transfers stored carbon into the atmosphere.

Excess fertilizer nutrients can drive eutrophication in water. Hypoxia is a low-oxygen condition that can follow.

Switch to the blank slide titled Same Planet, Different Gateways.
Use the text box control in the Keynote toolbar to add six compact text boxes.
Enter both cycles move matter through air, water, soil, and organisms in the first comparison text box.
Enter decomposers recycle both in the second comparison text box.
Enter carbon enters plant biomass mainly through photosynthesis and has major long-term storage in rocks and sediments in the third comparison text box.
Enter nitrogen must be fixed and repeatedly transformed, largely by microbes in the fourth comparison text box.
Enter fossil-fuel burning moves stored carbon rapidly into the atmosphere in the fifth comparison text box.
Enter excess fertilizer nutrients can cause eutrophication and hypoxia in water in the sixth comparison text box.

The slide now covers shared pathways before separating the carbon and nitrogen gateways. It also shows one major human disruption for each cycle.

Arrange the six text boxes in a compact comparison layout.
Increase the spacing around any crowded sentence.

You should be able to scan the shared features first. The differences and human impacts should remain distinct.

Animate and rehearse all five slides

Build order turns the static nitrogen diagram into an explanation. Each transformation should appear when the previous form has established where the nitrogen came from.

Return to The Nitrogen Journey slide.
Apply a Build In effect to each shape, arrow, and process label by using Add an Effect.
Set the fixation route to appear first.
Set the two nitrification routes to appear second.
Set the assimilation route to appear third.
Set the organic nitrogen and ammonification routes to appear fourth.
Set the denitrification route to appear fifth.
Click Preview to test the nitrogen pathway.

You should see nitrogen move from the atmosphere through usable chemical forms. The final build should return nitrate to atmospheric nitrogen.

Return to the Same Planet, Different Gateways slide.
Apply a Build In effect to each comparison text box.
Reveal the two shared features first.
Reveal the carbon difference second.
Reveal the nitrogen difference third.
Reveal the human-impact pair last.

The comparison should now move from common ground to the defining differences. The final build should connect both cycles to human activity.

Open the Play menu in Keynote.
Choose Rehearse Slideshow.
Advance through all five slides with the Space bar.

Reading speed is now your quality check. Every caption needs to remain visible long enough for its meaning to land.

Shorten any caption that cannot be read before the next build.
Save two-atoms-two-journeys.key.

Before the final rehearsal, predict which process should appear immediately after assimilation.

Open the Play menu again.
Choose Rehearse Slideshow.
Advance through all five slides with the Space bar.

You should see the failed shortcut followed by fixation, nitrification, assimilation, ammonification, and denitrification in a complete loop.

All five slides should present readable labels in a logical sequence. Your carbon slide and blocked nitrogen-shortcut slide should remain intact.

Your two cycle stories now work as one comparison. Next, you will add the complete script before exporting the presentation as a self-playing movie.

Caption and Export the Video

Your five-slide Keynote story now carries two atoms through their complete journeys. The blocked shortcut makes the key nitrogen difference visible.

A standalone video needs captions that remain readable without a live presenter. This step converts your saved presentation into a self-playing movie.

In this step, get ready to:

Add the complete script captions to all five slides.
Rehearse caption timing across the ordered builds.
Export a self-playing movie.

Add the complete script captions

Each caption turns the current diagram into a standalone explanation. The fixed script keeps the science consistent across all five slides.

Use the text-box control in the Keynote toolbar to place this caption on the Two Atoms, Two Journeys slide: Carbon and nitrogen are both recycled through Earth, but they travel in different forms and use different gateways.
Use the text-box control in the Keynote toolbar to place this caption on the The Carbon Journey slide: Photosynthesis moves carbon dioxide into plants. Feeding moves carbon through food webs. Respiration and decomposition return it, the ocean exchanges it with the air, and some carbon enters long-term geological storage.

You should now see a complete opening statement on slide 1. Slide 2 should now narrate the full carbon pathway.

Use the text-box control in the Keynote toolbar to place this caption on the Why Nitrogen Is Different slide: Atmospheric nitrogen cannot usually move straight into plants. Most plants cannot use N2 directly.
Use the text-box control in the Keynote toolbar to place this caption on the The Nitrogen Journey slide: Microbes open the nitrogen gateway. Fixation forms ammonium. Nitrification forms nitrite and nitrate. Plants assimilate usable nitrogen. Ammonification recycles it, and denitrification returns nitrogen to the atmosphere.

Slide 3 now explains why the direct atmospheric route fails. Slide 4 now explains how microbes open the usable nitrogen pathway.

Use the text-box control in the Keynote toolbar to place this caption on the Same Planet, Different Gateways slide: Both cycles connect air, water, soil, and life. Carbon centers on carbon dioxide, photosynthesis, and major geological storage. Nitrogen repeatedly changes form through microbial processes. Human activity can overload both cycles.
Resize any caption box whose text is clipped.
Save two-atoms-two-journeys.key.

You have given every slide its own part of the story. The saved presentation now contains the complete script.

Rehearse the five-slide story

Rehearsal tests whether each caption can be read before the next build. It also confirms that the failed shortcut appears before the microbial solution.

Before you start, predict whether the stop message stays visible long enough to make the failed route clear.

Open the Play menu.
Select Rehearse Slideshow.
Advance through the rehearsal with the Right Arrow key or the Space bar.
Read each caption at a natural pace before advancing.
Watch the blocked shortcut sequence before moving to the microbial pathway.

You should see the direct Atmospheric N2 route stopped before slide 4 introduces microbial transformations. Every caption should remain readable before the next build.

Timing or order needs work?

Select the affected slide in the slide navigator.
Click Build Order at the bottom of the Animate sidebar.
Drag any misplaced build into the correct sequence.
Increase the Delay before the next build when a caption needs more reading time.

Ask for help if the sequence still feels rushed: help me fix my Keynote build order and caption timing

Repeat the rehearsal after any timing adjustment.
Save two-atoms-two-journeys.key.

Your five-slide sequence now preserves the failed nitrogen shortcut before revealing the microbial solution. The complete script remains readable throughout the rehearsal.

Export the self-playing movie

Movie export packages the complete presentation into one .mov file. Self-playing timing lets someone watch the explanation without controlling the slides.

Open the File menu.
Select Export To.
Select Movie.
Open the Playback pop-up menu.
Select Self-Playing.

Why use self-playing playback?

Self-playing playback advances the slides through the timing controls you set. Builds configured to follow an earlier build keep their own timing.

Keynote exports the presentation as a .mov file. The result works as a standalone video.

Set the timing controls to match the reading pace from your rehearsal.
Open the Resolution pop-up menu.
Select a resolution for the exported movie.
Save the exported movie as carbon-vs-nitrogen-cycles.mov.

You should now see carbon-vs-nitrogen-cycles.mov in the location you selected for the export.

Before you open the movie, predict which caption is most likely to reveal a timing problem.

Locate carbon-vs-nitrogen-cycles.mov in Finder.
Open carbon-vs-nitrogen-cycles.mov.
Watch the movie from start to finish.

You should see all five slides advance automatically. Every caption should remain readable while the animations follow their planned order.

That completes the final handoff. Your carbon and nitrogen comparison now works as a captioned video that can teach the full story on its own.

Movie timing looks wrong?

Return to the movie export window in Keynote.
Confirm that Playback displays Self-Playing.
Increase the timing interval for any caption that disappears too quickly.
Export the movie again using the same filename.

Ask for help if the export still pauses or skips builds: help me troubleshoot my self-playing Keynote movie

Secret mission

Show Where the Cycles Meet

Bring carbon and usable nitrogen into the same plant through their correct gateways. Show both elements moving toward decomposers before you re-export the self-playing movie.

Clean Up Your Resources

Your presentation and movie stay entirely on your Mac with no ongoing cloud costs. Choose whether to keep both files, pause your editing session, or move them to Trash.

Resources you used:

Saved Keynote presentation named two-atoms-two-journeys.key.
Exported self-playing video named carbon-vs-nitrogen-cycles.mov.

Keep everything running

No action is needed. Choose this option if you want to revise your presentation or share the finished video.

Keep two-atoms-two-journeys.key in its current saved location.
Keep carbon-vs-nitrogen-cycles.mov in its current saved location.
Return to two-atoms-two-journeys.key whenever you want to revise the cycle animations.
Replay carbon-vs-nitrogen-cycles.mov whenever you want to share the completed comparison.

Pause - I'll come back to this later

This option closes your editing session while preserving both files for later.

Confirm two-atoms-two-journeys.key is saved in Keynote.
Close Keynote.
Close the window playing carbon-vs-nitrogen-cycles.mov.
Leave both files on your Mac until you are ready to continue.

Delete - I don't want to use this again

Remove both local files if you no longer need the presentation or its exported video.

In Finder, locate two-atoms-two-journeys.key.
Move two-atoms-two-journeys.key to Trash.
Locate carbon-vs-nitrogen-cycles.mov in Finder.
Move carbon-vs-nitrogen-cycles.mov to Trash.
Check Trash for both filenames.

You should see two-atoms-two-journeys.key and carbon-vs-nitrogen-cycles.mov listed in Trash. There are no online resources to remove.

Nice Work!

You did it! Your captioned, self-playing Keynote movie now follows carbon and nitrogen through Earth’s major reservoirs. Anyone who watches it can see why carbon enters plants through photosynthesis while nitrogen depends on microbial transformations.

You've learned how to:

Animate a carbon-cycle pathway that moves carbon through biological, ocean, and geological routes using labeled reservoirs and processes.
Reveal the nitrogen-cycle bottleneck before completing the pathway with fixation, nitrification, assimilation, ammonification, and denitrification.
Export a standalone comparison video with ordered animations and readable captions that explain reservoirs, chemical forms, microbial processes, and human impacts.
Secret Mission: Link carbon uptake and usable nitrogen assimilation inside the same plant. Return both elements toward decomposers in the final scene.

Ready to quiz yourself?