📦 比特与字节：信息的“个”与“斤”📦 Bit & Byte: the “piece” and “pound” of information
上一片里，💻小电脑学会了只用0和1数数。新问题来了：1个0算多少信息？一张照片又算多少？这一片，给信息称体重。Last leaf, 💻 Little Computer learned to count with just 0 and 1. New question: how much information is one 0? And one photo? This leaf weighs information.
第 1 步：1个比特，8个凑一字节Step 1: One bit; eight make a byte
先定最小单位——再看它们怎么打包。First fix the smallest unit — then see how they pack up.
1个0或1就是1比特（bit），它是最小的“个”。8个比特包成1字节（Byte），正好装一个字母。小电脑搬东西，都按“包”搬。One 0 or 1 is 1 bit — the smallest “piece”. Eight bits pack into 1 Byte, just enough for one letter. Little Computer always carries things by the “pack”.
有了“包”，可照片电影那么大，得换更大的包。Packs are good — but photos and movies are huge, so we need bigger packs.
1024字节=1KB，1024KB=1MB，1024MB=1GB，1024GB=1TB，像爬楼梯。一张照片几MB，一部电影几GB，每级大1024倍。1024 bytes = 1 KB, 1024 KB = 1 MB, 1024 MB = 1 GB, 1024 GB = 1 TB — like climbing stairs. One photo is a few MB, one movie a few GB; each step is 1024 times the last.
包有多大懂了，装一车要多久？运营商的数字游戏就在这。Pack sizes are clear — but how long does a truckload take? That is where the carrier's number game hides.
第 3 步：下载要多久，别被Mbps骗了Step 3: Download time — don't be fooled by Mbps
网速100Mbps里的小b是比特，除以8才是每秒12.5MB。下1GB电影约要80秒。记住：大B是字节，小b是比特，差8倍！The little b in 100 Mbps means bits; divide by 8 to get 12.5 MB each second. A 1 GB movie needs about 80 seconds. Remember: big B is Byte, little b is bit — 8 times apart!
🎮 你来当网管（30 秒）🎮 Your turn: be the network manager (30 seconds)
道理讲完了。先拖滑块，看文件大小和用时怎么变；再闯下面4关，算算下载和流量账。Theory done. First drag the slider and watch size and time move together; then clear 4 rounds of download and data math.
一句话记住它：1比特=1个0/1，1字节=8比特；KB/MB/GB/TB每级×1024；网速小b除以8才是每秒大B。Remember it in one line: 1 bit is one 0/1, 1 Byte is 8 bits; KB/MB/GB/TB grow 1024 times per step; divide the little-b speed by 8 to get big-B bytes per second.
bit是最小单位，Byte=8bit，正好装一个字母A bit is the smallest unit; a Byte is 8 bits — exactly one letterKB/MB/GB/TB，每一级都是1024倍KB/MB/GB/TB — each step is 1024 times the lastMbps是比特，除以8得MB/s；照片MB级、电影GB级Mbps counts bits; divide by 8 for MB/s; photos live in MB, movies in GB
内容参考 OpenStax 等公开教材，多来源核对 · AI 生成、人工审核 · 发现错误欢迎指正，帮这片叶子长得更好。Based on OpenStax and other open textbooks, cross-checked across sources · AI-generated, human-reviewed · Spotted a mistake? Tell us — help this leaf grow.
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