Forces in the Environment

Grade 8 · General Science

Semester 1 | Period 3 | Week 15

Download the Lessonotes Mobile Liberia app for faster lesson access on Android and iPhone.

Get it on Google Play Get it on the Apple App Store

Subject: General Science

Semester: 1

Period: 3

Week: 15

School Name:
Teacher’s Name:
Subject: General Science
Grade Level: Grade 8
Date: Week 15
Lesson Duration: 45 minutes
Week & Period: Week 15, Period 3
Topic: Forces in the Environment
Sub-topic: Learning Objectives
By the end of the lesson, students should be able to:

  1. Define and explain different forces in the environment.
  2. Identify real-life examples of forces in Liberia.
  3. Demonstrate simple experiments to illustrate these forces.

Previous Knowledge
Students already know:
• Basic concepts of energy (potential and kinetic)
• Motion and simple mechanics
Instructional Materials
• Textbook: General Science textbooks for Grade 8
• Teaching aids: spring scales, balls, inclined planes, friction materials (sandpaper, cloth), magnets, adhesive materials
• Students' notebooks and writing materials
Lesson Development – ABC Model
A – Anticipation (Warm-up / Starter)
Time: 5–10 minutes
Activity: The teacher will ask the class:
• Can you think of things that push or pull you at home or school?
• What happens when you slide a book on a table or drop an object?
The teacher will record responses on the board.
Teacher’s Role: Guide students to relate daily experiences to forces.
Learner’s Role:
• Share examples of forces from everyday life.
• Participate actively in discussion.

B – Building Knowledge (Main Lesson Body)

Time: 25–30 minutes

Teacher’s Role (Expanded & Detailed)

  1. Gravity
  • Defined as the force that pulls objects toward the center of the Earth.
  • Demonstration: Drop a stone, a leaf, and a piece of paper from the same height; discuss differences in fall due to air resistance but same gravitational pull.
  • Local relevance: Falling palm fruits, water flowing in rivers like the St. Paul and Mesurado.
  1. Inertia
  • Defined as the tendency of an object to resist any change in its motion.
  • Examples:
    • A stationary car will not move unless pushed.
    • A moving wheel continues unless brakes are applied.
  • Local relevance: Stopped carts in markets or boats in rivers.
  1. Friction
  • Defined as a force that resists motion between two surfaces in contact.
  • Demonstration: Slide a book on smooth vs rough surfaces; note the difference in motion.
  • Effects: Can slow down motion, produce heat, and help in walking or driving.
  • Local relevance: Shoes on dusty roads, tires on streets, grinding cassava on rough surfaces.
  1. Cohesion
  • Defined as the force that holds molecules of the same substance together.
  • Example: Water droplets forming beads on a leaf.
  • Local relevance: Rainwater on palm leaves or banana leaves.
  1. Adhesion
  • Defined as the force between molecules of different substances.
  • Example: Water sticking to glass, soil clinging to feet.
  • Local relevance: Water on windows or plastic sheets, mud sticking to hands during farming.
  1. Practical Demonstrations Using Local Materials
  • Stones: Dropped to show gravity.
  • Balls rolling on sandpaper or smooth floor: Friction.
  • Water droplets on palm leaves: Cohesion and adhesion.
  • Small cart or toy: Inertia demonstration.

 

Learners’ Activities (Expanded & Practical)

  1. Experiments
  • Gravity: Drop stones, leaves, and paper; record observations.
  • Friction: Roll balls on rough sand, smooth floor, and grass; compare distances.
  • Cohesion and Adhesion: Observe water droplets on leaves, glass, or plastic; discuss differences.
  • Inertia: Push a stationary object and observe motion; observe stopping objects.
  1. Recording Observations
  • Learners maintain notebooks with drawings, labels, and explanations for each force observed.
  1. Discussion
  • Identify forces acting in daily Liberian environment:
    • Gravity: fruits falling, water in rivers
    • Friction: walking on roads, tires on streets
    • Adhesion/Cohesion: rainwater, mud in gardens
    • Inertia: carts, bicycles, river canoes

 

Assessment Checks (Expanded)

  • Oral Questions:
    • Which force keeps you on the ground? (Gravity)
    • Give an example of friction in your school or home.
    • What force causes water droplets to stick together? (Cohesion)
  • Practical Checks:
    • Observe learners conducting experiments; can they correctly identify each force?
  • Written Exercise:
    • Identify forces in five given scenarios (e.g., rolling ball, falling fruit, water on leaf).

 

Notes (Expanded & Detailed)

  • Gravity: Pulls objects toward Earth; affects all masses equally; essential in everyday life.
  • Inertia: Keeps stationary objects still; keeps moving objects in motion unless an external force acts.
  • Friction: Opposes motion; can be beneficial (walking, vehicle brakes) or resistive (sliding objects).
  • Cohesion: Attraction between molecules of the same type; forms droplets.
  • Adhesion: Attraction between molecules of different types; helps water stick to surfaces.
  • Local relevance: Observing forces in markets, farms, rivers, construction, and home activities.

 

Extended Assignment

  1. Observe and list five examples each of gravity, friction, cohesion, and adhesion in your environment.
  2. Conduct a friction experiment at home using a ball or small object on different surfaces; record observations.
  3. Draw diagrams illustrating cohesion and adhesion with water on different surfaces.
  4. Explain in one paragraph how inertia affects moving and stationary objects in everyday life in Liberia.


C – Consolidation (Conclusion & Assessment)
Time: 5–10 minutes
Summary:
• Teacher asks learners to give one example for each force discussed.
Evaluation Method (Expanded):
• Exit slip/quiz: Students write:

Define friction and give an example.

Explain adhesion with a local example.
• Teacher reviews and provides oral feedback.
Assignment (Expanded):
• Observe and list five examples of forces in your home or community.
• Design a simple experiment to demonstrate friction or gravity.
Follow-up Activity:
• Encourage learners to bring small objects to class next week for a forces demonstration.
Differentiation / Inclusive Strategies
• Struggling Learners: Use clear, simple examples like dropping a stone, sliding a book.
• Advanced Learners: Explore combined forces or Newton’s laws application.
• Students with Disabilities: Use tactile objects and peer assistance for experiments.
Teacher’s Reflection (After Class)
• What worked well? ______________________________________________________
• What needs improvement? _________________________________________________
• Students’ engagement level: □ High □ Medium □ Low