Understanding Time: Reading and Converting Units

Lesson 1 of 6: Distance, Time and Speed

In this lesson:

• Read and write time correctly
• Tell apart point of time from duration
• Convert hours, minutes, and seconds

What You Will Learn Today

By the end of this lesson, you should be able to:

1. Read and write time in hours, minutes and seconds
2. Distinguish between a point of time and a duration
3. Convert time units (hours → minutes → seconds)
4. Identify arrival time and departure time

Time Is All Around You

Think about your day so far:

• What time did you wake up this morning?
• What time did school start today?
• How long have you been in class right now?

The Three Units of Time

Write 8:30 a.m. (colon, not a dot)

Point of Time vs Duration

These are two completely different ideas:

Point of Time or Duration? Classify Each

• "School starts at 8:00 a.m." → point of time
• "We've been in school for 3 hours" → duration
• "The lesson is 45 minutes long" → duration
• "It is 2:30 p.m." → point of time

WHEN → point of time · HOW LONG → duration

Quick Check: What Type Is This?

Is this a point of time or a duration?

"The maths lesson ends at 2:30 p.m."

Think before advancing...

Answer: It Is a Point of Time

2:30 p.m. tells us WHEN the lesson ends — not how long it lasts.

That makes it a point of time.

Departure Time and Arrival Time

• Departure time — when the journey begins (you leave)
• Arrival time — when the journey ends (you reach)

The duration is the time between departure and arrival.

Both departure and arrival are points of time.

Worked Example: Kampala to Jinja Bus

A bus leaves Kampala at 9:00 a.m. and arrives in Jinja at 11:00 a.m.

Your Turn: Mary's Walk to School

Mary leaves home at 7:30 a.m. and arrives at school at 8:00 a.m.

• What is her departure time?
• What is her arrival time?
• What is the duration of her journey?

Work it out, then advance for the answer.

Mary's Walk to School: Answers

• Departure: 7:30 a.m.
• Arrival: 8:00 a.m.
• Duration: 8:00 − 7:30 = 30 minutes

Always include the unit — "30" alone is not a complete answer.

Check-In: Identify Departure, Arrival, Duration

A boda-boda leaves Nakawa at 2:00 p.m. and arrives at Wandegeya at 2:30 p.m.

1. What is the departure time?
2. What is the arrival time?
3. What is the duration of the journey?

Think through all three before the next slide.

Boda-Boda Check-In: All Three Answers

1. Departure: 2:00 p.m.
2. Arrival: 2:30 p.m.
3. Duration: 30 minutes

Two points of time, one duration — all from the same journey.

How to Convert Between Time Units

Multiply or Divide? The Conversion Rule

Rule: smaller unit → multiply · larger unit → divide

Worked Example: Converting to Smaller Units

Example 1: Convert 2 hours to minutes

Example 2: Convert 3 minutes to seconds

Going smaller → multiply by 60 ✓

Worked Example: Converting to Larger Units

Example 3: Convert 180 seconds to minutes

Example 4: Convert 120 minutes to hours

Going larger → divide by 60 ✓

Guided Practice: You Decide the Operation

Complete these conversions. The direction is given — you choose multiply or divide.

a) 5 hours = ___ minutes (going smaller — so...?)

b) 4 minutes = ___ seconds (going smaller — so...?)

Write your working, then advance for the answers.

Guided Practice: Check Your Answers

a) 5 hours = 5 × 60 = 300 minutes

b) 4 minutes = 4 × 60 = 240 seconds

Going smaller → multiply × 60 ✓

Independent Practice: Three Conversion Problems

Solve these on your own:

1. 240 seconds = ___ minutes
2. 1.5 hours = ___ minutes
3. 6 minutes = ___ seconds

Try all three, then advance.

Independent Practice: Check Your Working

1. 240 ÷ 60 = 4 minutes (divide — going larger)
2. 1.5 × 60 = 90 minutes (multiply — going smaller)
3. 6 × 60 = 360 seconds (multiply — going smaller)

Always show working and write the unit.

Quick Check: Answer All Five Questions

1. Define point of time and duration.
2. A matatu leaves at 10:00 a.m. — arrival or departure?
3. Convert 4 hours to minutes.
4. Convert 300 seconds to minutes.
5. Leave 7:00 a.m., arrive 7:45 a.m. — duration?

Answer all five, then advance.

Quick Check: All Five Answers

1. Point of time = a specific moment (WHEN); duration = HOW LONG
2. Departure — the matatu is leaving
3. 4 × 60 = 240 minutes
4. 300 ÷ 60 = 5 minutes
5. 7:45 − 7:00 = 45 minutes

Key Takeaways from Today's Lesson

✓ Point of time = WHEN · Duration = HOW LONG

✓ Departure = when you leave · Arrival = when you reach

✓ Smaller → × 60 · Larger → ÷ 60

1 hour = 60 min, not 100

Write 8:30 a.m. · Always include your unit

Next Lesson: Distance and Speed

In Lesson 2:

• What distance means (km, m)
• What speed means — how fast something moves
• The formula: Speed = Distance ÷ Time

Homework: Record your morning journey times, convert them, and solve the boda-boda problem in your exercise book.