Science (EVS K-5) · Class 7

Active learning ideas

Spherical Mirrors: Concave and Convex

Active learning works for spherical mirrors because students need to see, touch, and sketch how curved surfaces bend light. When they hold mirrors and trace rays themselves, the abstract rules about focal points and image types become clear.

• CBSE Learning Outcomes
• CBSE: Light - Class 7

• 20–45 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Stations Rotation
• 45 min · Small Groups

Stations Rotation: Mirror Observation Stations

Prepare three stations with concave mirror, convex mirror, and ray box. Place objects at focus, between pole and focus, and beyond centre of curvature. Groups observe images, note position, size, nature, and sketch ray diagrams. Rotate every 10 minutes and compare findings.

Differentiate between the types of images formed by concave and convex mirrors.

Facilitation Tip

During the Mirror Observation Stations, place a lamp or torch behind each mirror so students can see the reflected light patterns clearly.

What to look for

Provide students with two small mirrors, one concave and one convex. Ask them to hold each mirror at different distances from their hand and record in a table: 'Mirror Type', 'Object Distance (approx.)', 'Image Characteristics (erect/inverted, magnified/diminished, clear/fuzzy)'.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 02

• Experiential Learning
• 25 min · Pairs

Pairs: Ray Diagram Drawing

Provide worksheets with mirror outlines and object positions. Pairs draw principal rays: parallel to axis, through focus, to pole. Label image properties and discuss how rays change for concave versus convex. Share one diagram per pair with class.

Explain the uses of concave mirrors in headlights and shaving mirrors.

Facilitation Tip

While pairs draw ray diagrams, remind students to use a ruler and label the principal axis, focal point, and object position for accuracy.

What to look for

Draw a simple ray diagram on the board showing light rays reflecting off a concave mirror. Ask students to identify the type of image formed and predict its characteristics (real/virtual, inverted/erect, magnified/diminished) based on the object's position.

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Activity 03

• Experiential Learning
• 30 min · Whole Class

Whole Class: Application Simulation

Use a torch and concave mirror to demonstrate headlight beam focus on a wall. Switch to convex mirror for rear-view simulation with toy car. Students predict and observe field of view differences, then note in notebooks.

Analyze why convex mirrors are preferred as rearview mirrors in vehicles.

Facilitation Tip

For the Application Simulation, ask guiding questions like, 'What happens if the object moves closer to the mirror?' to deepen thinking.

What to look for

Pose the question: 'Imagine you are designing a new type of security camera for a large store. Which type of spherical mirror would you choose for the camera's lens, and why? Consider the area you need to monitor.'

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Activity 04

• Experiential Learning
• 20 min · Individual

Individual: School Mirror Survey

Students locate concave and convex mirrors in school bathrooms, vehicles, or labs. Record image types formed and one application each. Compile class chart to discuss findings.

Differentiate between the types of images formed by concave and convex mirrors.

Facilitation Tip

During the School Mirror Survey, ensure students sketch the mirror’s curvature first before predicting image properties to avoid rushed conclusions.

What to look for

Provide students with two small mirrors, one concave and one convex. Ask them to hold each mirror at different distances from their hand and record in a table: 'Mirror Type', 'Object Distance (approx.)', 'Image Characteristics (erect/inverted, magnified/diminished, clear/fuzzy)'.

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

A few notes on teaching this unit

Teachers often start with simple demonstrations before moving to hands-on work because spherical mirrors confuse students when explained only through theory. Avoid rushing into formulas; let students observe how images flip or shrink first. Research shows that students learn best when they sketch rays themselves and relate them to real objects like torches or rear-view mirrors.

By the end of these activities, students will confidently explain why concave and convex mirrors form different images and select the right mirror for real-life uses. They will also correct common misconceptions by comparing their own observations with ray diagram predictions.

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Watch Out for These Misconceptions

• During Mirror Observation Stations, watch for students who assume concave mirrors always make images bigger. Ask them to move their hand closer and farther to observe changes in image size and position.

  During Ray Diagram Drawing, remind students that the object’s position relative to the focus determines image type. After pairs complete their diagrams, ask them to compare sketches with their station observations to correct the idea that concave mirrors always magnify.

• During Application Simulation, watch for students who think convex mirror images can be projected on a screen.

  During the School Mirror Survey, give students a small screen or paper and ask them to try capturing the image. When they see no projection, discuss why virtual images cannot be caught on screens.

• During Mirror Observation Stations, watch for students who believe convex mirrors show a narrower view than plane mirrors.

  During the School Mirror Survey, ask students to measure the angle of their field of view using a protractor held at arm’s length for both plane and convex mirrors to compare the coverage.

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Methods used in this brief

• Stations Rotation
• Experiential Learning