Comparison

Back in Time vs Molecules by Theodore Gray

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Back in Time

Explore the history of the Universe, Earth, Life, and Civilization through an immersive, interactive journey. This app uses custom animations, timelines, and interesting facts to bring historical events to life. It's designed to help users understand the connections between events and see the bigger picture.

Highlights
  • Interactive timeline of events
  • Custom animations and videos
  • Over 350 remarkable images
  • Little-known interesting facts
  • Offline access
  • Multilingual support
Features
Read full description

• "The coolest history textbook you’ll find on the iPad" - The New York Times • Winner of the WSA Mobile Award • Top1 iPad Book in US, UK, FR, ES, China… and 34 more Countries • Featured by The New York Times (Top10 iPad Apps of the year) • Featured by the American Photo Magazine (Top 10 Photo eBooks of the year) For iPhone/iPod touch download - Back in Time for iPhone Back in Time will take you on a stunning exploration of the history of our Universe, Earth, Life and Civilization. A journey through time where each event is documented with social and historical context, several images, an illustrative timeline and little-known interesting facts. Custom made animations bring those events to life, creating an interesting, immersive learning experience. An imaginary clock will guide you through this quest, proposing a simple analogy: the entire Universe started 24 hours ago. The Big Bang, the source of time and space, is the first event in our journey – the clock reads 0:00 hours. Today, 13.7 billion years later, the clock reads midnight. In between is a sequence of key events that has brought us to where we are today. Explore them, place them in perspective, see how they relate and understand the connections. We invite you to take a step back and see the whole picture. :::: REVIEWS :::: “...a beautifully executed lesson on the history of the universe and the evolution of life on earth. Great for high school students or parents who’d like to tutor younger children and enjoy a first-rate experience of their own...” - Bob Tedeschi, The New York Times “The iPad could use more apps like this one.” - The Daily “...the best iPad apps are those that combine coffee table-styled books with the fluid nature of the iPad’s interface. Back in Time is just that, it’s the story of the entire history of our universe made interactive on the iPad.” - Casey Chan, Gizmodo (App of the Day) “Back in Time is utterly gorgeous in its presentation. (...) The app is so easy to navigate that it is a delight to explore. Landka could scarcely have done a better job in putting everything together.” - Gwen Phua, Appmodo :::: FEATURES :::: Designed for iPad; 47 chapters; Over 350 remarkable images; 60+ amazing animations and videos; 40+ illustrated timelines; More than 200 little-known interesting facts; Music by the composer Rodrigo Leão; Developed in 7 different languages (English, Spanish, German, French, Portuguese, Japanese and Chinese); No internet connection required.

About

Molecules by Theodore Gray

Explore the molecular world with interactive simulations and detailed information. Discover how elements form compounds and witness the dynamic dance of quantum mechanics through touch. This app offers a fun and educational way to understand the nature of substances.

Highlights
  • Touch-interactive molecular dynamics simulation
  • Bend, squeeze, and shape molecules
  • Adjust temperature to observe reactions
  • Full text of the 'Molecules' book
  • Interactive object rotations
  • Dozens of 'still life videos'
Features
Read full description

INCLUDED IN BEST OF 2014 “Few iOS apps are as thoughtfully designed as Molecules, and even fewer combine superb visuals with clear writing that encourages exploration.” – Macworld “Molecules uses its predecessor as a springboard to further greatness.” – Stuff A book about molecules, and a chance to touch, stretch and twist them! Molecules by Theodore Gray is the extraordinary sequel to The Elements, the bestselling book and app. It continues the story of the elements to show how they are assembled into the rich diversity of compounds, chemicals, molecules, rocks, and stuff that make up our world. The app includes an important world first: a touch-interactive molecular dynamics simulation that lets you poke and prod hundreds of different molecules, seeing how each one reacts to your touch. Molecules are not static things – they twist, turn, vibrate, and spin in an elaborate and beautiful dance of quantum mechanics. The app incorporates the NAMD simulation engine developed by the Theoretical and Computational Biophysics Group at the University of Illinois. These are serious, scientifically accurate simulations. A few minutes playing with them will give you a deeper intuition about the true nature of molecules than years of study on paper. And while they are serious science, they are also a whole lot of fun to play with! In addition to the amazing wiggling molecules, the app contains the entire book of Molecules, with all the objects interactively rotatable so you can see them from all sides. Going further than The Elements, the app includes dozens of innovative and intriguing “still life videos” that reveal the true nature of substances through close-up interactive video. Features include: • Try out the first ever touchscreen-interactive molecular dynamics • Bend, squeeze and shape 348 different molecules using multiple fingers • Increase or decrease the temperature and see how molecules react • Read the full text of all 14 chapters of Molecules by Theodore Gray • Understand the movements of molecules in a special chapter for the app • See over 500 videos and rotations of incredible objects photographed by Nick Mann If you like Molecules by Theodore Gray, don’t forget to rate it and leave a review.

Screenshots

Molecules by Theodore Gray4 screens

Verdict

The call

Back in Time and Molecules by Theodore Gray both sit at 4.6 stars, but that hides the real split: 84% of Back in Time's written reviews are positive against 75% of Molecules by Theodore Gray's. Back in Time also leads on price ($7.99 vs $9.99). Molecules by Theodore Gray's advantage is device support (3 vs 1) and iOS requirement (12.1 vs 16.0). On rating, ratings volume, update cadence and ads there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Back in Time costs $7.99 and Molecules by Theodore Gray $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.6 for Back in Time against 4.6 for Molecules by Theodore Gray. Both are backed by a comparable volume of ratings — 25 and 29 respectively. Written reviews are what separate them: 84% of Back in Time's written reviews are positive against 75% of Molecules by Theodore Gray's.

UpkeepUpdate frequency

Back in Time ships an update every 7 months, Molecules by Theodore Gray every 6 months. The most recent releases landed on October 7, 2026 and October 13, 2026 respectively.

Scorecard4 real differences · 6 level
Back in Time versus Molecules by Theodore Gray: the parameters behind the verdict, then further details
ParameterBack in TimeMolecules by Theodore Gray
Price$7.99 — better$9.99
Rating4.6 (25 ratings)4.6 (29 ratings)
Positive reviews83.7% of reviews — better74.7% of reviews
Number of ratings2529 — better
Update frequencyEvery 7 monthsEvery 6 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPadiPhone, iPad, iPod — better
Requires iOS16.012.1 — better
Further details — not scored
Size836 MB745 MB
Age rating4+12+
DeveloperLandkaNatureGuides Ltd.

Customer experience

Back in Time

All ratings25 ratings
Positive92.0%
Neutral4.0%
Negative4.0%
Written reviews43 reviews
Positive83.7%
Neutral7.0%
Negative9.3%

Molecules by Theodore Gray

All ratings29 ratings
Positive89.7%
Neutral3.4%
Negative6.9%
Written reviews87 reviews
Positive74.7%
Neutral17.2%
Negative8.0%

In-app purchases

None

Back in Time

No in-app purchases

None

Molecules by Theodore Gray

No in-app purchases

Questions

Is Back in Time free?
Back in Time costs $7.99, with no in-app purchases.
Is Molecules by Theodore Gray free?
Molecules by Theodore Gray costs $9.99, with no in-app purchases.
Which has better reviews, Back in Time or Molecules by Theodore Gray?
Back in Time and Molecules by Theodore Gray are both rated 4.6 out of 5 on the App Store, from 25 and 29 ratings respectively.
Do Back in Time or Molecules by Theodore Gray have ads?
Neither Back in Time nor Molecules by Theodore Gray shows ads.
Which is updated more often, Back in Time or Molecules by Theodore Gray?
Back in Time ships an update every 7 months, and Molecules by Theodore Gray every 6 months. Most recently, Back in Time was updated on October 7, 2026 and Molecules by Theodore Gray on October 13, 2026.

Other comparisons