# ReactionFlash vs Decay Tree

The clearest difference is rating: ReactionFlash at 4.8 against Decay Tree's 4.1. ReactionFlash also leads on in-app purchases (none vs 2) and ads (none vs shown). Decay Tree's advantage is review sentiment (100% vs 81%) and iOS requirement (12.0 vs 14.0). On price and device support there is nothing between them.

Both are free to download. Decay Tree sells 2 one-off in-app purchases. ReactionFlash asks for nothing beyond the download.

ReactionFlash holds the better App Store score, 4.8 against 4.1. That said, the two scores are not equally well evidenced: ReactionFlash has 41 ratings behind it against 7, so its average is the more settled of the two. Written reviews complicate that: 81% of ReactionFlash's written reviews are positive against 100% of Decay Tree's, so the app with the better star average is not the one people write more warmly about.

ReactionFlash ships an update every 4 months, Decay Tree every 11 months. The most recent releases landed on October 7, 2026 and September 28, 2026 respectively.

## The numbers

| Metric | ReactionFlash | Decay Tree |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (41 ratings)](https://appshunter.io/ios/app/reactionflash/id432080813/reviews)** | [4.1 (7 ratings)](https://appshunter.io/ios/app/decay-tree/id1066023546/reviews) |
| Number of ratings | **41** | 7 |
| Positive reviews | 80.6% of reviews | **100.0% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 4 months** | Every 11 months |
| Monetization | **Free** | Free with in-app purchases |
| Size | 37 MB | 53 MB |
| Requires iOS | 14.0 | **12.0** |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Elsevier Limited](https://appshunter.io/developer/1437273934) | [Gustaf Holst](https://appshunter.io/developer/1066023545) |

## What reviewers say

### ReactionFlash

[App page](https://appshunter.io/ios/app/reactionflash/id432080813)

This app serves as a comprehensive flashcard-style learning tool for named chemical reactions. It provides detailed information on reaction mechanisms and examples from scientific literature, with a quiz mode to test user knowledge.

**Highlights:** Learn named chemical reactions, Understand reaction mechanisms, View literature examples, Quiz mode for knowledge testing, Flashcard interface

**Features:** macOS Compatibility

**In-app purchases:** none


### Decay Tree

[App page](https://appshunter.io/ios/app/decay-tree/id1066023546)

This educational app visually represents nuclear decay chains for various nuclides. It graphically displays decay modes and half-lives, alongside detailed tables and graphs of spin, specific activity, and emitted particles.

**Highlights:** Visualizes decay chains, Graphical display of decay modes, Graphical display of half-lives, Tabulated details of spin, specific activity, emitted particles, Graphs of spin, specific activity, emitted particles

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Radiation Table | $0.99 | one-time |
| Remove Ads | $1.99 | one-time |


## Frequently asked questions

### Is ReactionFlash free?

ReactionFlash is free to download, with no in-app purchases.

### Is Decay Tree free?

Decay Tree is free to download, with in-app purchases available.

### Which has better reviews, ReactionFlash or Decay Tree?

ReactionFlash is rated higher. ReactionFlash averages 4.8 out of 5 from 41 ratings, while Decay Tree averages 4.1 from 7 ratings.

### Do ReactionFlash or Decay Tree have ads?

Decay Tree shows ads; ReactionFlash does not.

### Which is updated more often, ReactionFlash or Decay Tree?

ReactionFlash ships an update every 4 months, and Decay Tree every 11 months. Most recently, ReactionFlash was updated on October 7, 2026 and Decay Tree on September 28, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*