How This Text Is Built
RI.5.5
Read the text, then answer the questions.
What Sleep Is For
Sleep is not switching off. Parts of the brain are busier asleep than awake. Two claims are well supported. The first is that sleep consolidates memory: during deep sleep, the day's experiences are replayed and moved from short-term storage into long-term. Interrupt deep sleep and recall of the previous day drops measurably. The second is that sleep clears waste. The spaces between brain cells widen during sleep, and fluid washes through, removing proteins that build up while awake. A third claim — that a particular number of hours suits everybody — is not supported. Need varies with age and between individuals, and self-reported sleep is unreliable. Teenagers are a special case. Their body clocks genuinely shift later at puberty, which is a biological fact rather than a preference, and school start times mostly ignore it.
- 1. What overall structure does this text use?
Why the Rails Are That Far Apart
Standard gauge is 4 feet 8½ inches. It is a strange number, and the reason is historical rather than engineering. Early railways were built by people who had built tramways for collieries, and those had used the wheel spacing of the carts already in use. Nobody chose it; it was inherited. Isambard Kingdom Brunel did choose. He built the Great Western at 7 feet ¼ inch, and by most measures it was better: faster, steadier, and able to carry more. He lost anyway. By the 1840s, more of the network was already standard gauge, and a train cannot run on a track it does not fit. Parliament settled it in 1846. Between 1846 and 1892 the Great Western converted its entire route. The final conversion took a single weekend and about four thousand men. The best design does not always win. The one that connects to everything else does.
- 1. What overall structure does this text use?
LessonPrint · RI.5.5 · Set 25 · free to copy for classroom use