Our eyes enable us to see the things in our surroundings. But, there are limitations to our vision. For example, we cannot see the things that are too far and too near. Also, we are unable to see things which are too small or too close to each other; like microorganisms. To see such small things, people use a lens or a combination of lenses. A magnifying glass (a hand lens) is a single convex lens that enlarges the image of an object. A microscope is an assembly or an arrangement of two or more lenses that enlarges the image even more. Form groups of two or three students each, and conduct the following tasks.

Materials Required

Task 1: Two magnifying lenses per group

Task 3: (For each group) 2 glass slides, 2 pieces of paper (approximately 2cm х 2cm), ballpoint pen, pencil, transparent adhesive tape etc.

Task 4: (For each group) 2 glass slides, a newspaper cutting that has letters ‘e’ and ‘s’, transparent adhesive tape. The letters need to be in small (regular) font, not from headlines that are printed in large and bold.

Task 5: Slides, coverslips, salt, Hibiscus flower (Gurhal in Hindi, Jaswand in Marathi), Baker’s Yeast, onion, safranin stain (optional).

Task 6: Transparent plastic ruler.

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