Time (II): minutes & seconds

1Summary 重點摘要

1 min = 60 seconds.

2Vocabulary cards Vocabulary

3Step by step Steps

1. Part 1: How long is a second?The second is the unit for measuring very short times: saying 'good morning' takes about 1 second, writing your own name about 3 seconds, and one deep breath about 4 seconds. On a clock face the thinnest hand that moves fastest is the second hand, and each small step it takes is 1 second. Why learn the second? Because many things in life are measured accurately in seconds, such as how many seconds a 100 m run takes, a 30-second microwave burst, or a 15-second advertisement. Try feeling it first: quietly count 1, 2, 3 in your head, about one second each. A common mistake is to mix up the second hand with the minute hand; one small step of the minute hand is 1 minute while one small step of the second hand is 1 second, sixty times apart, so identify the second hand first whenever you read a clock.
2. Part 2: 1 minute = 60 secondsWatch the second hand make one full trip on the clock face: setting out from 12, passing every small step, and finally returning to 12 — 60 small steps in all, taking exactly 1 minute, so 1 minute = 60 seconds. Why watch it with your own eyes? Because this relation is the foundation for converting between minutes and seconds; having seen the second hand go round once, the rules — minutes to seconds multiply by 60, seconds to minutes divide by 60 — become clear and reasonable. You can also run a small experiment: count 60 beats in your head without looking at the clock, then check against it, and you will find a minute feels longer than expected. A common mistake is to think 1 minute = 100 seconds, bringing decimal habits into time; time runs in sixties, so 1 minute = 60 seconds and 1 hour = 60 minutes must be kept firmly in mind.
3. Part 3: Minutes to secondsTo change minutes into seconds, multiply by 60: 2 minutes = 2 × 60 = 120 seconds; 5 minutes = 5 × 60 = 300 seconds; half a minute = 30 seconds. Why multiply? Because 1 minute is 60 seconds, so several minutes are that many sixties, and converting minutes to seconds makes the number 60 times bigger. Picture it on the clock face: 3 minutes means the second hand goes 3 laps, each lap 60 seconds, so 3 laps are 3 × 60 = 180 seconds. There is a trick for checking direction: a smaller unit carries a bigger number, so after converting to seconds the number should be larger than the minutes. A common mistake is to reverse the direction, computing 2 ÷ 60 for 2 minutes, or to slip in the multiplication, writing 5 × 60 as 250. Before writing, tell yourself 'minutes to seconds, the number grows', and then choose multiplication.
4. Part 4: Seconds to minutesTo change seconds into minutes, divide by 60: 180 seconds = 180 ÷ 60 = 3 minutes; 240 seconds = 4 minutes. If the number of seconds is not a multiple of 60, use division with a remainder: 90 ÷ 60 = 1 remainder 30, that is 1 minute 30 seconds; likewise 150 seconds = 2 minutes 30 seconds. Why divide? Because every 60 seconds makes 1 minute, so look for how many sixties fit inside: the quotient is the minutes and the remainder is the extra seconds. After converting, the number gets smaller — 180 seconds is only 3 minutes — following the rule 'bigger unit, smaller number'. A common mistake is to drop the remainder, writing 90 seconds as 1 minute, or to turn the remainder straight into a decimal, writing 90 seconds as 1.3 minutes although 30 seconds is 0.5 and 90 seconds is really 1.5 minutes; for beginners, writing '1 minute 30 seconds' is the safest form.
5. Part 5: Mixed formsA 400 m run took 1 minute 25 seconds — that is a mixed form. To change it into all seconds: 1 minute 25 seconds = 60 + 25 = 85 seconds. The other way round, 85 seconds can also be written back as 1 minute 25 seconds, since 85 ÷ 60 = 1 remainder 25. The forms name the same duration; choose what the question asks for, and when comparing speeds, converting everything to seconds is the most convenient. Why learn mixed forms? Because daily life and sports results both favour minutes and seconds: a 100 m swim timed at 1 minute 40 seconds converts to 60 + 40 = 100 seconds. A common mistake is to turn 1 minute 25 seconds into 125 seconds by simply gluing the two numbers together; the correct path is to change the 1 minute into 60 seconds first and then add 25, so every conversion of mixed forms passes through 'minutes to seconds, then add'.
6. Part 6: Minutes and seconds in lifeMinutes and seconds serve us everywhere: brushing teeth takes 2 minutes, that is 2 × 60 = 120 seconds; one microwave burst is 30 seconds; a 100 m run takes about 15 seconds; one green light lasts about 30 seconds. In PE lessons a stopwatch records the run, and a result of 1 minute 50 seconds converts to 60 + 50 = 110 seconds, so after matching the units classmates can compare fairly. Why master minutes and seconds? Because planning time, recording results and obeying signals all rely on them: keeping a shower within 10 minutes means within 600 seconds. A common mistake is to estimate times wildly, thinking brushing teeth took 2 seconds or 20 minutes; practise 'guess first, then measure' — predict how many seconds a task takes and check with a clock, and your sense of time will sharpen.

4Diagrams Diagrams

5Worked example Example

6Common mistakes Mistakes

7Quick check Quick check

8Recap Recap

• 1 minute = 60 seconds
• Minutes to seconds × 60; seconds to minutes ÷ 60
• One sweep of the second hand = 1 minute
• Mixed form: 1 min 25 sec = 85 seconds
• Match units before comparing times