Class: Basic 3
Term: 3rd Term
Week: 1
Age: 7 – 8 years
Duration: 60 minutes
Subject: Mathematics
Curriculum Theme: Measurement
Previous Lesson: Measurement of Length
Topic: Weight
Content/Learning Area:
- Introducing grams and kilograms as standard units of measurement of weight.
- Finding and recording weights of objects using standard units.
- Finding weights of small objects (e.g. packet of sugar, tin of milk, textbooks) and recording in grams.
- Comparison of weights of different objects – light and heavy objects.
Performance Objectives
By the end of the lesson, pupils should be able to:
Cognitive Domain:
- Identify the concept of weight as how heavy or light an object is.
- State standard units of weight (grams and kilograms).
- Associate grams (g) with lighter objects and kilograms (kg) with heavier objects.
- Compare the weights of two or more objects using terms like ‘heavier than’, ‘lighter than’, and ‘same weight as’.
Affective Domain:
- Show appreciation for the need for standard units in measuring weight accurately.
- Develop curiosity in exploring the weights of different objects around them.
- Cooperate with peers during group activities involving weighing and comparing objects.
Psychomotor Domain:
- Demonstrate the use of simple weighing scales (e.g., kitchen scale, balance scale) to find the weight of objects.
- Record the weights of objects using the correct standard units (g or kg).
- Physically compare the weight of objects by lifting them and stating which is heavier or lighter.
Social Domain:
- Work collaboratively in groups to weigh and compare objects.
- Communicate findings about object weights clearly to others.
- Respect turns and share materials during practical weighing activities.
Instructional Materials
To deliver this lesson, the teacher will use the following materials:
- Various objects of different weights (e.g., textbooks, exercise books, tins of milk/Milo, packets of sugar/biscuits, stones, pencils, erasers, water bottle, empty bottle).
- Simple weighing scales (e.g., kitchen scale, bathroom scale – if available, balance scale).
- Charts showing standard units of weight (grams and kilograms) and their abbreviations (g, kg).
- Chart or pictures of different types of weighing scales.
- Chart showing examples of objects commonly weighed in grams and kilograms.
- Notebooks and pencils for recording.
Reference Materials
The following resources were used in planning this lesson:
- Nigerian 9 – Years Basic Education Curriculum
- Abuja Educational Resource Centre Scheme of Work
- NAPPS National Unified Scheme of Work
- How to Teach Kids About Weight and Mass – Science Buddies (https://www.sciencebuddies.org/science-fair-ideas/science-at-home/how-to-teach-kids-about-weight-mass)
- Primary 3 Mathematics Measurement: Weight and Capacity – Kofa Education (https://kofa.education/lesson/primary-3-mathematics-measurement-weight-and-capacity-1)
Rationale for the Lesson
Understanding weight helps learners interact meaningfully with their physical environment. Introducing standard units equips them with foundational skills for estimation, comparison, and accurate measurement—critical for both academic and real-life applications.
Prerequisite/Previous Knowledge
Pupils have previously learned about measuring length and are familiar with basic comparison vocabulary like “longer,” “shorter,” “heavier,” and “lighter.”
Lesson Content
Meaning of Weight
Weight is a measure of how heavy or light an object is. It tells us the force of gravity pulling down on an object. When we lift something, we feel its weight. Objects that are bigger or made of denser material usually weigh more than smaller or less dense objects, but this is not always the case. For example, a small stone might weigh more than a large ball of cotton wool.
Introducing Standard Units of Weight: Grams (g) and Kilograms (kg)
Just like we use metres and centimetres to measure length, we use standard units to measure weight so everyone understands the measurement. The three main standard units of weight we use are grams and kilograms.
Milligram (mg):
A milligram is used to measure very tiny weights. It is the smallest unit of weight.
Examples: medicine, salt, powder.
1,000 mg = 1 g
Gram (g):
A gram is used to measure light objects.
Examples: a pencil, an eraser, a biscuit, an apple.
1 g = 1,000 mg
Kilogram (kg):
A kilogram is used to measure heavy objects.
Examples: a bag of rice, a textbook, a person.
1 kg = 1,000 g
Finding and Recording Weights of Objects using Standard Units
To find the exact weight of an object using standard units, we need to use a weighing scale. There are different types of scales like kitchen scales, bathroom scales, or laboratory scales. When using a scale, we place the object on it, and the scale shows the weight in grams or kilograms. It is important to read the scale carefully and note down the measurement along with the correct unit (g or kg). For example, a scale might show ‘500 g’ for a packet of sugar or ‘2 kg’ for a bag of garri. We then record this number and unit.
Comparison of Weights of Different Objects – Light and Heavy Objects
We can compare the weights of objects to see which one is heavier, which is lighter, or if they weigh about the same.
- Qualitative Comparison: Without a scale, we can sometimes estimate by lifting. An object feels ‘heavy’ if it requires a lot of effort to lift, and ‘light’ if it requires little effort. We can say Object A is heavier than Object B, or Object B is lighter than Object A.
- Quantitative Comparison: Using a weighing scale gives us an exact measurement. We can weigh two objects and compare their weights in the same unit (e.g., compare 500 g of sugar and 200 g of biscuits). Since 500 g is more than 200 g, the sugar is heavier than the biscuits. If one object is measured in grams and another in kilograms, we should convert one unit so they are the same for comparison (e.g., convert 1 kg to 1000 g to compare it with 500 g). Objects with higher weight values are heavier, and objects with lower weight values are lighter. If two objects have the same weight value, they weigh the same.
Teaching Methods
To deliver this lesson, the teacher will adopt the following methods: Discussion, Explanation, Demonstration, Practical Activity, Question and Answer, Visual Aids, Group Work.
Instructional Procedures
To deliver this lesson, the teacher will adopt the following steps:
| Step | Time | Teaching Skills | Teacher’s Activity | Pupils’ Activity | Learning Point |
|---|---|---|---|---|---|
| Step 1: Introduction | 5mins | Set Induction | Greets the pupils. Reviews the previous lesson on Length. Holds up two objects (e.g., a textbook and a pencil) and asks, “Which one is harder to lift? Why?”. Guides discussion towards the idea of how heavy something is. Introduces the topic: Weight. | Respond to greetings. Recall previous lesson. Observe objects and answer questions. Participate in discussion. | Activating prior knowledge. Introducing the concept of ‘heaviness’ and weight. |
| Step 2: Concept of Weight | 10mins | Explanation, Discussion | Explains what weight is – how heavy or light an object is. Uses examples from the classroom. Discusses how we feel weight when lifting objects. | Listen attentively. Share their own ideas about heavy and light objects. Ask questions. | Understanding the basic definition of weight. |
| Step 3: Introducing Standard Units (g and kg) | 10mins | Explanation, Visual Aids | Introduces milligrams (mg), grams (g) and kilograms (kg) as standard units of weight. Shows charts with ‘g’ and ‘kg’ abbreviations. Explains that ‘g’ is for lighter objects and ‘kg’ is for heavier objects, giving examples for each. Mentions that 1 kg = 1000 g. | Observe charts. Repeat the names and abbreviations of the units. Give examples of objects they think are weighed in g or kg. | Learning the standard units of weight and their abbreviations. Associating units with appropriate object weights. |
| Step 4: Finding and Recording Weights (Practical Activity) | 15mins | Demonstration, Practical Activity, Group Work | Divides pupils into groups. Provides each group with some objects and a weighing scale (if available and safe for use). Demonstrates how to place an object on the scale and read the weight in grams or kilograms. Guides groups to weigh their objects and record the weights in their notebooks using the correct units. Circulates to assist groups. | Work in groups. Observe the demonstration. Practice using the scale (if available). Weigh objects and record weights in notebooks. Collaborate with group members. | Learning how to use a weighing tool (if available). Practicing reading and recording weights using standard units. |
| Step 5: Comparing Weights | 10mins | Discussion, Practical Activity | Reviews the recorded weights from the group activity. Selects pairs of objects weighed and asks pupils to compare their weights using the recorded data (“Is the textbook heavier or lighter than the tin of milk? How do you know?”). Discusses comparison terms: heavier than, lighter than, same weight as. Allows pupils to physically lift some objects to feel the difference and compare with recorded weights. | Share their recorded weights. Compare weights of objects based on the recorded numbers. Use comparison terms correctly. Physically compare objects by lifting. | Understanding how to compare weights using both qualitative (feeling) and quantitative (measured) methods. Using correct comparison vocabulary. |
| Note Taking | 5mins | Explanation, Writing | Provides key notes on the board covering the definition of weight, standard units (g and kg), abbreviations, and examples. Instructs pupils to copy the notes into their notebooks. | Copy notes from the board into their notebooks. | Consolidating key concepts in written form. |
| Evaluation | 3mins | Question & Answer, Assessment | Asks pupils to answer questions like: “What unit would you use to weigh a packet of sugar?”, “Which is heavier, 500g of rice or 1kg of stones? Why?”, “Show me two objects in the classroom and tell me which is lighter.” Collects notebooks to check recorded weights. | Respond to questions individually. Show and compare objects. Submit notebooks. | Assessing understanding of standard units, relative weights, and comparison. |
| Closure | 2mins | Instructional, Cognitive, Social | Summarizes the main points of the lesson: what weight is, the units gram and kilogram, how we measure and compare weight. Commends pupils for their participation and effort during the activities. Relates learning to real-life scenarios (e.g., buying things in the market). | Listen to the summary. Receive positive reinforcement. Connect learning to real life. | Reinforcing key learning points. Encouraging application outside the classroom. Fostering a positive learning environment. |
Lesson Keywords (Key terms used in the lesson)
- Weight – How heavy or light an object is.
- Heavy – Having great weight.
- Light – Having little weight.
- Gram (g) – A standard unit used for measuring the weight of lighter objects.
- Kilogram (kg) – A standard unit used for measuring the weight of heavier objects.
- Weighing Scale – A tool used to measure weight.
- Compare – To look at objects to see how they are similar or different in weight.
Lesson Evaluation
Pupils will be evaluated based on their participation in class discussions, ability to answer questions during the lesson and evaluation session, accuracy in recording weights during the practical activity (if applicable), and correct use of terms like ‘gram’, ‘kilogram’, ‘heavier than’, and ‘lighter than’.
Assignment/Homework
- List 3 objects in your home that you think weigh in grams (g).
- List 3 objects in your home that you think weigh in kilograms (kg).
- Look at a food item package at home (like rice or sugar). What is its weight shown in? (e.g., 500g, 1kg, 2kg).
Differentiation
For slower learners:
- Provide more direct guidance during practical activities, helping them position objects on the scale and read the numbers.
- Focus primarily on the qualitative comparison (heavy/light) and identifying objects that are weighed in grams vs. kilograms with clear examples.
- Provide simplified charts with fewer examples.
- Pair them with more advanced learners during group work.
For advanced learners:
- Challenge them to estimate weights before using the scale.
- Introduce the concept that 1 kg = 1000 g and ask them to convert simple weights (e.g., “How many grams are in 2 kg?”).
- Ask them to compare the weights of three or more objects and order them from lightest to heaviest.
- Encourage them to explore different types of weighing scales and how they work.
For visual/auditory/kinesthetic learners:
- Visual: Use charts, pictures of scales and objects, and write keywords clearly on the board.
- Auditory: Explain concepts clearly, use songs or rhymes if available, encourage verbal comparison and discussion.
- Kinesthetic: Incorporate hands-on activities using real objects and weighing scales, allow pupils to physically lift and compare objects.
Note for Teachers
Ensure enough objects of varying weights are available for practical activities. If weighing scales are not available, focus more on the qualitative comparison of heavy and light objects and introducing grams and kilograms as abstract units with clear examples of what each unit measures. Safety should be a priority if using actual scales. Monitor group activities closely to ensure participation and understanding.