Chapter 1 Section 4

1. Chapter 1 Section 4 Objectives: 1.4.1 Describe the measurement system most scientists us. 1.4.2 Explainhow light microscopes are similar and different 1.4.3 Describe two common laboratory techniques 1.4.4 Explain why it is important to work safely in biology.

2. Section 4 Tool and Techniques • Common measurement system-metric system • Based on multiples of 10 • Length is measured in meters • Mass is measured in gram • Volume is measured in liter • Temperature is measured in degree Celsius (°C)

3. Section 4 Tool and Techniques • Light Microscopes • A compound light microscope is a microscope that shines light through a specimen and has two lenses to magnify an image. • Four major parts of a compound light microscope are the ocular lens, objective lens, stage, and light source.

4. Section 4 Tool and Techniques • Light Microscopes • The ocular magnifies the image. (10x) • The objective lens enlarges the specimen. • The stage is a platform that supports slides with specimens. • The light source is a light bulb that provides light for viewing images.

5. Section 4 Tool and Techniques • Magnification and Resolution • Magnification is the increase of an object’s apparent size. • Resolution is the power to show details clearly in an image.

6. Section 4 Tool and Techniques

7. Section 4 Tool and Techniques • Electron Microscopes • In an electron microscope, a beam of electrons produces an enlarged image of the specimen. • Electron microscopes provide greater magnification and resolution than light microscopes.