Lesson Notes By Weeks and Term v5 - Grade 5

Lesson Video

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Performance objectives

• Solve word problems involving time intervals.
• Read, interpret, and solve problems with temperature in degrees Celsius.
• Solve practical problems with measurement conversions (length, mass, volume).
• Apply all these skills to solve combined, real-world problems.
• Estimate everyday measurements and check if your guess is reasonable.

Lesson summary

This week, we're diving into the practical world of time, temperature, and everyday measurements. Understanding these concepts is crucial for everyday life in South Africa. From knowing when to catch the taxi to school, understanding the weather forecast so you know what to wear, to measuring ingredients for your favorite koeksisters recipe, these skills are essential. We will build upon your existing knowledge and apply it to solve realistic, everyday problems. This week's focus will be on applying these skills within a problem-solving context.

Lesson notes

Time Calculations: Understanding time is vital for scheduling and managing daily activities. Remember that time is measured in seconds, minutes, hours, days, weeks, months, and years. We will focus on calculations involving hours and minutes.

Key Conversions: 1 minute = 60 seconds 1 hour = 60 minutes 1 day = 24 hours Calculating Time Intervals: To find the time interval between two events, subtract the starting time from the ending time. When subtracting, remember to borrow 60 minutes from the hours if necessary.

Example 1: A taxi leaves Soweto at 7:15 AM and arrives in Johannesburg at 8:30 A

M. How long did the taxi ride take?

Solution: Ending time: 8:30 AM Starting time: 7:15 AM Time interval: 8:30 - 7:15 = 1 hour and 15 minutes. The taxi ride took 1 hour and 15 minutes.

Example 2: A soccer match starts at 3:00 PM and is scheduled to last for 90 minutes. What time will the match end?

Solution: Start time: 3:00 PM Duration: 90 minutes (which is 1 hour and 30 minutes, since 90/60 = 1 remainder 30)

End time: 3:00 PM + 1 hour 30 minutes = 4:30 PM The soccer match will end at 4:30 P

M. Temperature: Temperature measures how hot or cold something is. In South Africa, we use degrees Celsius (°C).

Understanding Temperature Scales: 0°C is the freezing point of water. 100°C is the boiling point of water. Normal body temperature is around 37°

C. Temperature Differences: To find the difference between two temperatures, subtract the lower temperature from the higher temperature.

Example 3: The temperature in Cape Town is 28°C during the day and drops to 18°C at night. What is the difference in temperature?

Solution: Daytime temperature: 28°C Nighttime temperature: 18°C Temperature difference: 28°C - 18°C = 10°C The temperature difference is 10°

C. Example 4: This morning the temperature in Johannesburg was 5°

C. By lunchtime, it had increased by 12°

C. What was the temperature at lunchtime?

Solution: Morning temperature: 5°C Increase in temperature: 12°C Lunchtime temperature: 5°C + 12°C = 17°C The temperature at lunchtime was 17°

C. Everyday Measurement Problems: We use measurement every day to determine length, mass (weight), and volume (capacity). Remember the relationships between different units.

Key Conversions: Length: 1 meter (m) = 100 centimeters (cm), 1 kilometer (km) = 1000 meters (m)

Mass: 1 kilogram (kg) = 1000 grams (g)

Volume: 1 liter (L) = 1000 milliliters (mL)

Example 5: A piece of cloth is 2.5 meters long. How many centimeters long is it?

Solution: Length in meters: 2.5 m Conversion factor: 1 m = 100 cm Length in centimeters: 2.5 m 100 cm/m = 250 cm The cloth is 250 cm long.

Example 6: A bag of potatoes weighs 5 kg. How many grams does it weigh?

Solution: Weight in kilograms: 5 kg Conversion factor: 1 kg = 1000 g Weight in grams: 5 kg 1000 g/kg = 5000 g The bag of potatoes weighs 5000 g.

Example 7: A bottle contains 1.5 liters of juice. How many milliliters of juice are in the bottle?

Solution: Volume in liters: 1.5 L Conversion factor: 1 L = 1000 mL Volume in milliliters: 1.5 L 1000 mL/L = 1500 mL The bottle contains 1500 mL of juice. Guided Practice (With Solutions)

Question 1: Nomusa starts baking koeksisters at 9:45 AM and finishes at 11:15 A

M. How long did she spend baking?

Solution: Ending time: 11:15 AM Starting time: 9:45 AM Time interval: 11:15 - 9:45 First, subtract the minutes: 15 -

4

5. We can't do this directly, so we borrow 1 hour (60 minutes) from the 11 hours. This gives us 10 hours and 75 minutes. Now, subtract: 10:75 - 9:45 = 1 hour and 30 minutes. Nomusa spent 1 hour and 30 minutes baking.

Question 2: The temperature in Durban is 25°C. The temperature in Johannesburg is 13°

C. What is the temperature difference between the two cities?

Solution: Durban temperature: 25°C Johannesburg temperature: 13°C Temperature difference: 25°C - 13°C = 12°C The temperature difference is 12°

C. Question 3: A roll of pap is 850 grams. How many kilograms is this?

Solution: Weight in grams: 850 g Conversion factor: 1 kg = 1000 g To convert grams to kilograms, we divide by 1000: 850 g / 1000 g/kg = 0.85 kg The roll of pap is 0.85 kg.

Question 4: Thando is building a fence that is 6 meters long. He has already built 350 cm. How much further does he need to build, in centimeters?

Solution: Total length of fence: 6 meters Length already built: 350 cm We need to convert everything to the same unit.

Let's convert the total length to cm: 6 meters 100 cm/meter = 600 cm Length remaining to build: 600 cm - 350 cm = 250 cm Thando needs to build another 250 cm. Independent Practice (Questions Only)

A movie starts at 6:30 PM and lasts for 2 hours and 15 minutes. What time will the movie end? The temperature in Pretoria rises from 16°C to 31°C. By how many degrees did the temperature rise? A container holds 3.2 liters of water. How many milliliters of water does it hold? Sarah buys 2.5 kg of apples at the market. How many grams of apples did she buy? A train journey from Cape Town to Johannesburg takes 26 hours.