# HMH Science Dimensions vs Merge Explorer

The clearest difference is rating: Merge Explorer at 4.1 against HMH Science Dimensions's 2.3. Merge Explorer also leads on review sentiment (46% vs 25%) and ratings volume (279 vs 17). HMH Science Dimensions's advantage is in-app purchases (none vs 4) and iOS requirement (9.0 vs 15.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Merge Explorer sells 4 in-app purchases, starting at $9.99 per month. HMH Science Dimensions asks for nothing beyond the download.

Merge Explorer holds the better App Store score, 4.1 against 2.3. That said, the two scores are not equally well evidenced: Merge Explorer has 279 ratings behind it against 17, so its average is the more settled of the two. Written reviews point the same way: 25% of HMH Science Dimensions's written reviews are positive against 46% of Merge Explorer's.

HMH Science Dimensions ships an update every 2 months, Merge Explorer monthly. The most recent releases landed on October 21, 2026 and October 23, 2026 respectively.

## The numbers

| Metric | HMH Science Dimensions | Merge Explorer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [2.3 (17 ratings)](https://appshunter.io/ios/app/hmh-science-dimensions/id1384935325/reviews) | **[4.1 (279 ratings)](https://appshunter.io/ios/app/merge-explorer/id1453098606/reviews)** |
| Number of ratings | 17 | **279** |
| Positive reviews | 25.0% of reviews | **46.2% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Monthly** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 227 MB | 1.3 GB |
| Requires iOS | **9.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Houghton Mifflin Harcourt](https://appshunter.io/developer/409368007) | [Merge Apps](https://appshunter.io/developer/1253049593) |

## What reviewers say

### HMH Science Dimensions

[App page](https://appshunter.io/ios/app/hmh-science-dimensions/id1384935325)

This augmented reality app transforms book covers into interactive science experiments. Students can scan their textbooks to launch 3D models and explore concepts like weather, solar energy, and the solar system. It's designed to make learning engaging and fun for young students.

**Highlights:** Augmented reality science experiments, Scan book covers to activate content, Interactive 3D models, Explores various science topics, Engaging learning experience, Group or pair work friendly

**Features:** macOS Compatibility

**In-app purchases:** none


### Merge Explorer

[App page](https://appshunter.io/ios/app/merge-explorer/id1453098606)

Explore over 100 interactive science simulations using a smartphone and a Merge Cube. Investigate volcanoes, sharks, the solar system, and more with hands-on activities and quizzes. Ideal for K-8 students learning science at school or home.

**Highlights:** Over 100 science simulations, Interactive Merge Cube experiences, Hands-on learning activities, Built-in quizzes, NGSS-aligned K-8 curriculum, Physical, Life, and Earth/Space Science topics

**Features:** macOS Compatibility, Family Sharing, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Merge EDU Individual | $9.99 | per month |
| Explorer Premium Monthly | $9.99 | per month |
| Merge EDU Individual | $99.99 | per year |
| Explorer Premium Annual | $99.99 | per year |

**What reviewers like**

- 👍 Easy for young students
- 💡 Flexible for lesson needs
- 🔬 Used for research and experiments
- 💡 Introduces new content exploratorily
- 🤩 Engaging and versatile for learning

**What reviewers complain about**

- 💰 Expensive purchase
- 💰 Forced subscription for software
- 💰 Cannot view software before paying
- 💰 Money trap
- 💰 Only for rich people

**Reported bugs**

- App crashes on iPad
- App crashes when pressing play
- Camera not working in app
- Black screen when using cube or camera
- VR function broken

**Requested features**

- Make the app free to play
- Add more fun things, not just learning
- Bring back the fun apps (time bomb, block courses)
- Allow users to create their own games for the merge cube
- Add a way to reset quizzes for class sets of devices


## Frequently asked questions

### Is HMH Science Dimensions free?

HMH Science Dimensions is free to download, with no in-app purchases.

### Is Merge Explorer free?

Merge Explorer is free to download, with in-app purchases available.

### Which has better reviews, HMH Science Dimensions or Merge Explorer?

Merge Explorer is rated higher. HMH Science Dimensions averages 2.3 out of 5 from 17 ratings, while Merge Explorer averages 4.1 from 279 ratings.

### Do HMH Science Dimensions or Merge Explorer have ads?

Neither HMH Science Dimensions nor Merge Explorer shows ads.

### Which is updated more often, HMH Science Dimensions or Merge Explorer?

HMH Science Dimensions ships an update every 2 months, and Merge Explorer monthly. Most recently, HMH Science Dimensions was updated on October 21, 2026 and Merge Explorer on October 23, 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.*