Grainfall: Falling Sand
Physics sandbox particle toy
Free · In‑App Purchases
Sand, water, oil, fire, plants and stone. Pour them together and see what happens. Record anything you make and share the video. No levels, no goals, no timer.
Grainfall is a falling sand toy. Pick a material, drag across the screen, and watch it react with whatever is already there.
Sand piles up and slides back down. Dig a hole and water will find it. Oil floats on top of water, and oil burns. Plants drink from standing water and creep toward it. Fire spreads, leaves ash behind, and boils water into steam that drifts up, cools off, and comes back down as rain.
There is no score and nothing to unlock by playing. What you get is twelve materials that all react to each other, and the fun is working out how. Build a glass tank and fill it with acid, since glass is the one thing acid cannot chew through. Pour lava into water and it sets into stone. Light one end of a gunpowder trail and follow it along.
Hit record at any point and Grainfall turns what happened into a video, with sound built from the same events you just watched. Save a world and it keeps a picture of itself in your list. Send one to a friend as a small file and it opens straight into their copy.
FREE
• Sand, water, oil, plant, fire and wall
• The full simulation, running at 60fps
• Record and export video, with a small watermark in the corner
• Your world saves itself and is waiting when you come back
PRO - One time purchase
• Six more materials: acid, glass, lava, ice, gunpowder, fireworks
• Video export with the watermark gone
• Save as many worlds as you want, name them, load them back
• Send worlds to friends as .grain files
• Four color themes
• Tilt gravity, so leaning your phone pours everything sideways
A FEW THINGS WORTH TRYING
• Float oil on water and drop in a single flame
• Fill a glass tank with acid
• Pour lava into the sea and watch the steam come off it
• Light a gunpowder trail at one end
• Set off enough fireworks that the falling sparks catch your plants
Every material makes its own sound. No account, no ads, nothing collected, and it all works offline.
Ratings & Reviews
The developer, John Haas, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- John Haas
- Size
- 23.9 MB
- Category
- Simulation
- Compatibility
Requires iOS 14.0 or later.
- iPhone
Requires iOS 14.0 or later. - iPad
Requires iPadOS 14.0 or later. - iPod touch
Requires iOS 14.0 or later. - Mac
Requires macOS 11.0 or later.
- iPhone
- Languages
- English
- Age Rating
13+
- 13+
- Infrequent
Cartoon or Fantasy Violence
Contains
User-Generated Content
- In-App Purchases
Yes
- Grainfall Pro $0.99
- Copyright
- © 2026 Jake Haas