Biology Experiment - Microscopy

The scene lets students explore and review an experiment designed to develop scientific enquiry skills. By reviewing the apparatus, and key information, students will review and evaluate the experiment to deepen their understanding on obtaining evidence and data to draw a suitable conclusion about their observation. In this case, observing a sample of cells.

# Learning objectives

1: Use a Light Microscope to obtain a Clear Image of Onion Cells{.info}

2: Prepare a Suitable Slide of Onion Cells for Observation{.info}

3: Draw and Label Cells from the Observation of Onion Skin{.info}

4: Calculate Magnification from a Scaled Image{.info}

# 1: Preparing a Slide{.objective .objective1}

In this section the apparatus needed to prepare a microscope slide can be observed. A method of preparation a slide involves removing a sample of onion cells from an onion, placing it on a glass slide, staining it with iodine, and covering it with a cover slip. Students should enter the scene and describe a step-by-step process of preparing a slide.

# 2: Obtaining an Image{.objective .objective2}

In this section using a microscope will be described. Understanding the function of a microscope should be reviewed and how it will lead to a clear image that can be observed. Students should understand the importance of a higher magnification to obtain a microscope image of cells from their onion sample. Students should explore the scene and discuss how a microscope works and how it should be used to obtain a clear image.

# 3: Drawing a Suitable Microscopy Diagram{.objective .objective3}

In this section the drawing techniques will be described on how to produce a clear image representative of the observations made under the microscope. The diagram should be presented with clear, solid lies with no shading or etching. It should be clearly labelled, the magnification used should be indicated, and a T-bar should be drawn to illustrate a scaled measurement from the eye piece graticule. Students should enter the scene and review the magnification equation, which they will need to apply in any given example.

# Teacher Resources

### Download Teacher Notes

[](https://data.avncloud.com/activities/789460/files/Biology%20Experiment+-+Microscopy+Teacher+Notes-no+quiz.pdf?date=1674483679&size=681046&md5=0c9877a9eb6d7f879f82de18234c6724)

### Download Student Quiz Answers Document

[](https://data.avncloud.com/activities/789462/files/Biology%20Experiment+-+Microscopy+Teacher+Notes+with+quiz+answers.pdf?date=1674483946&size=731762&md5=65b0ad918c78ff04b5450c3fd2226cd1)

### Download Student Quiz Document

[](https://data.avncloud.com/activities/789461/files/Biology%20Experiment+-+Microscopy+Teacher+Notes-Student+Quiz.pdf?date=1674483839&size=98653&md5=cc801555cfc72f4f067dea7aef5e5e94)

# Science Labs Sample Questions

**Biology Experiment - Microscopy**

## Practice Question

1. A Student wants to use a microscope to view a sample of cells.

The student adds a drop of iodine stain to her sample.

Which Statement best describes when a stain might be used to view a sample of tissue?

- When a specimen is too thick for light to pass through.
- When the specimen is colourless.
- When there aren’t many sub-cellular structures present in the cells.
- When a cover slip in not being used.
1. Rearrange these steps in the correct order for preparing a microscope slight of onion cells.
2. Place slide on microscope stage.
3. Add one or two drops of iodine to the sample.
4. Use forceps to remove a sample of onion cells from an onion.
5. Place onion cells sample on a glass microscope slide.
6. Place a glass cover slip on onion cells sample.
1. A student drew a scaled diagram of a cell she observed, and the cell image measured 5cm. The Image se drew was from a sample she observed under a microscope using a magnification of x 400.

Calculate the actual size of the cell she observed (show your working): \_______________\_ µm

## Mark scheme

1. A: When the specimen is colourless. (The idea is that subcellular structures absorb the stain to make them visible for observation).
2. A: c, d, b, e, a. This question is designed to target the method in preparation of a slide for observation.
3. A: 125 µm. The question is designed to get students to apply the equation magnification = image size/actual size. Students should convert the image size from cm to µm to give 50,000µm. hey should rearrange the equation to magnification/image size. They should be reminded of the equation triangle.