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Lenses and Microscopes
- Our eyes can see only things above a certain size.
- A curved piece of glass can make small things look bigger.
- This curved glass is called a lens.
- Better lenses led to the microscope.
- The microscope opened up a hidden world of tiny creatures.
Example 1 — Magnifying Glass
- A magnifying glass is held over an ant.
- The ant's body looks much bigger.
- So a lens helps us see fine details.
Example 2 — Water-Filled Flask
- A flask of water is placed on a book.
- The letters under it look larger.
- So the flask acts like a magnifying glass.
Important Points
- A lens is shaped thick in the middle and thin at the edge.
- A microscope makes tiny things look many times bigger.
Definition — Lens
A lens is a curved piece of glass, thick in the middle and thin at the edge, that makes small things look bigger.
Definition — Organism
An organism is any living being, such as a plant or an animal.
Materials needed
A round-bottom glass flask.
Water and a cork.
An open book and a magnifying glass.
Water and a cork.
An open book and a magnifying glass.
Procedure
Fill the flask with water and close it with the cork.
Place it on an open book and look at the letters.
Then use a magnifying glass to look at a small ant.
Place it on an open book and look at the letters.
Then use a magnifying glass to look at a small ant.
Observation
The letters look larger through the flask. The ant's details are clearer through the magnifying glass.
Explanation
The water-filled flask bends light like a lens. So it magnifies, just like a magnifying glass.
◆ Summary
- Flask of water on a book.
- Letters look bigger.
- It acts like a lens.
- Lenses help us see small things.
🏭 Ever Heard Of — Hooke and Leeuwenhoek
In 1665, Robert Hooke used an early microscope to look at a thin slice of cork.
The first cells
He saw many tiny empty spaces, like a honeycomb, and called each one a cell. This was the first use of the word "cell" in science. Around the same time, Antonie van Leeuwenhoek made better lenses and was the first to see bacteria. He is called the Father of Microbiology.
