Comparison

天球模擬器 vs 單字雪球

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

Head to head
About

天球模擬器

Features
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Astronomy Teaching System is an interactive application designed for learning and exploring basic astronomy. Through visual simulations, it helps users intuitively understand complex celestial geometry and the patterns of celestial motion. Core Features: • Celestial Sphere and Diurnal Motion Simulation: Observe the celestial coordinate system with support for toggling Right Ascension RA and Declination Dec grid lines. Users can freely adjust the observer's latitude 90°N to 90°S via a slider to see real-time changes in the starry sky and stellar tracks at different latitudes. • Dual Perspectives and Relative Motion: Provides Earth Rotation and Celestial Rotation modes, allowing you to thoroughly understand the principles of diurnal motion from different reference frames. You can tap stars on the screen to hide or show specific celestial bodies. • Solar Path through the Seasons: Explore the changing position of the sun on the ecliptic. Use an intuitive date slider 1/1 to 12/31 to observe changes in solar altitude angles and daylight tracks during the equinoxes and solstices. • Space and Earth Mode Toggle: In Space Mode, view Earth's orbital path and axial tilt in the solar system from a bird's-eye perspective. In Earth Mode, view the daily solar path in the local sky from an observer's first-person perspective. • Rotation and Revolution Control: Supports independent toggling of Earth's rotation and revolution, with an acceleration feature for quick demonstrations of long-term astronomical changes. This application offers intuitive touch-to-zoom and perspective adjustment features, making it an ideal supplementary learning tool for students, educators, and astronomy enthusiasts.

About

單字雪球

This app uses spaced repetition to help you master difficult vocabulary. It features a built-in dictionary, multiple learning modes, and progress tracking. Designed for those who already know many words, it focuses on reinforcing what you struggle to remember.

Highlights
  • Spaced Repetition System (SRS)
  • 18,000+ built-in word bank
  • Four learning modes (read, quiz, spell, sprint)
  • Built-in Cambridge Dictionary
  • Progress sync via iCloud
  • No account, ads, or subscriptions
Features
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你早就認得很多單字了——真正該花時間的,是那些一直記不牢的幾百個字。 單字雪球用 Anki 式的間隔重複(SRS)排程,把「已經會的」快速分流歸檔,把「還不熟的」在你快要忘記的那一天送回眼前。每天只要清完「今日要讀」,記住的字就像雪球一樣越滾越大。 ■ 18,000 字內建字庫,打開就能背 收錄 18,000 多筆單字,含 KK 音標、中文詞性解釋、英文釋義,以及 79,000 條例句與搭配詞。Level 1~6 對應大考字表分級,想背哪幾級自己勾。完全內建、離線可用,不必匯入字卡,也不用自己建牌組。 ■ 四種學習模式,看心情換 ・讀單字:到期複習自動穿插新字,四鍵評分(再一次/困難/良好/簡單),按鈕上直接顯示下次複習的間隔,按下去之前就知道結果。 ・寫題目:四選一克漏字。答錯的字和誤選的字會自動標記為不熟;題目句子裡的任何一個字都能點開查字義。 ・拼字測驗:看中文解釋和首字母,把英文拼出來。題數、是否納入還沒學過的字、是否影響複習排程,都可以自己決定。 ・清單衝刺:把任意單字丟進自訂清單(考前衝刺、課本第三課、老是搞混的字…),用不計分的循環卡片反覆翻,全部記住才結束。 ■ 為「已經會很多字」的人設計 第一次看到的字按「簡單」就直接歸檔為精通,永遠不再排程、也不佔用每日新字配額;只有測驗答錯或你手動標記不熟時才會被拉回來。每日新字量也會隨著複習積壓自動縮減,不會一次雪崩。 ■ 查得到,才記得住 ・變化型態查找:輸入 studied、running、cities 都能找到原形。 ・中文反查:忘了英文怎麼拼,打中文一樣查得到。 ・內建劍橋辭典:想查更深入時,直接在 app 內開啟 Cambridge Dictionary。 ・單字發音:點一下就聽美式發音。 ・個人筆記:搭配詞、字根、諧音,想怎麼記就怎麼寫,之後複習時會一起出現。 ■ 每天都會想打開 ・連續天數紀錄,加上可自訂時間的每日提醒通知。 ・主畫面與鎖定畫面小工具,一眼看到今天還有幾個字要讀。 ■ 進度存在你自己的 iCloud 學習進度透過 iCloud 私有資料庫自動同步,換手機、重裝 app 都會自動回填。沒有帳號、沒有廣告、沒有訂閱,也不收集你的學習資料。 現在開始滾你的單字雪球。

Screenshots

天球模擬器4 screens
單字雪球4 screens

Verdict

The call

The clearest difference is in-app purchases: 天球模擬器 at none against 單字雪球's 1. 天球模擬器 also leads on iOS requirement (13.0 vs 17.0). On price, update cadence, ads and device support 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

Both are free to download. 單字雪球 sells 1 one-off in-app purchase. 天球模擬器 asks for nothing beyond the download.

UpkeepUpdate frequency

天球模擬器 ships an update every 3 days, 單字雪球 every 4 days. The most recent releases landed on October 25, 2026 and October 29, 2026 respectively.

Scorecard2 real differences · 7 level
天球模擬器 versus 單字雪球: the parameters behind the verdict, then further details
Parameter天球模擬器單字雪球
PriceFreeFree
Rating—5.0 (1 ratings) — better
Number of ratings—1 — better
Update frequencyEvery 3 days — betterEvery 4 days
AdsNoNo
In-app purchasesNo — betterYes
Monetization—Free
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS13.0 — better17.0
Further details — not scored
Size19 MB34 MB
Age rating4+4+
DeveloperHan-Chiang ChouCHENG-LI CHANG

In-app purchases

None

天球模擬器

No in-app purchases

1 purchases

單字雪球

One-time1
  • 記憶線索$2.99

Questions

Is 天球模擬器 free?
天球模擬器 is free to download, with no in-app purchases.
Is 單字雪球 free?
單字雪球 is free to download, with in-app purchases available.
Do 天球模擬器 or 單字雪球 have ads?
Neither 天球模擬器 nor 單字雪球 shows ads.
Which is updated more often, 天球模擬器 or 單字雪球?
天球模擬器 ships an update every 3 days, and 單字雪球 every 4 days. Most recently, 天球模擬器 was updated on October 25, 2026 and 單字雪球 on October 29, 2026.

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