Cover lesson · Science · Year 9 · Advanced

Organising and sharing microscope images of cells

DCF: Interacting and collaborating → Storing and sharing

Name: Class: Date:

Cover teacher: you need no subject knowledge

Print: this sheet, one per pupil, and the stimulus sheet “The Year 9 microscope photos: a folder in a mess”, one between two. No computers and no microscopes are needed. Pupils need a calculator. Every measurement is printed as a number, so nobody needs a ruler.

Run: 4 min read the stimulus in pairs · 8 min Step 1, magnification · 10 min Step 2, real cell sizes · 6 min Step 3, design a naming rule · 10 min Step 4, rename the files · 6 min Step 5, folders and versions · 6 min Step 6, sharing · 8 min Step 7, storage and back-up. Total 58 minutes.

Collect: this sheet. The digital skill is storing and sharing files safely: naming, organising, sharing and backing up. Steps 1, 2 and 7 are also assessed numeracy (measurement): magnification, converting mm to micrometres and converting kB, MB and GB, all with working shown. Check that pupils have written the working, not just answers.

What you are doing

A Year 9 class took photos of cells under the microscope. The photos now sit in one badly named folder on one laptop. The Head of Science wants them on the school’s cloud storage so every Year 9 pupil can revise from them. You will work out what each photo shows and how big the cells really are, then plan how the photos should be named, organised, shared and backed up.

Step 1: magnification

Use the lab notes (stimulus section 3) and the fact card (section 4).

(a) Complete the total magnification for each photo of cells.

File	Eyepiece	Objective	Total magnification (show the multiplication)
A
C
E
F
J

(b) Group 2 forgot to write down the objective lens for photo G. Photo G is the same onion slide as photo A, where an onion cell is 0.25 mm long (you will check this in Step 2(a)). In photo G the cell is 10 mm long. Work out the total magnification of photo G, then which objective lens was used. Show your working.

Step 2: how big are the cells really?

Use actual size = image size ÷ magnification. Give each answer in mm, then convert it to micrometres (µm). Show every step.

Feature	Working: actual size in mm	Actual size in µm	Sensible? Compare with the fact card
(a) Onion cell, photo A
(b) Cheek cell, photo C
(c) Onion nucleus, photo E
(d) Pondweed cell, photo F
(e) Chloroplast, photo F

(f) A pupil in group 1 wrote “the cheek cell is 0.06 µm”. Explain what they did wrong and how the fact card could have warned them.

(g) Group 3 wanted a whole onion cell in photo E. Use image size = actual size × magnification to work out how long a 0.25 mm onion cell would be at photo E’s magnification. The photo is 80 mm wide on screen. Would a whole cell fit?

Step 3: design a naming rule

Every file name must record 4 things: the sample, the magnification, the date taken written as YYYY-MM-DD, and the group. It also needs a version number. Decide the order, and how to separate the parts. Write magnification as x100, because the × sign causes problems in file names.

(a) Your rule, written as a pattern, and one example:

(b) Give 2 more rules everyone must follow (think about spaces, capital letters and pupils’ names).

(c) Why is 2026-09-15 better than 15-09-2026 when a computer sorts files by name?

Step 4: rename the files

Decide what happens to each file. If it is kept, write its new name using your rule. If not, give the reason.

File	Keep or remove?	New name, or the reason for removing it
A
B
C
D
E
F
G
H
I
J

Step 5: folders and versions

(a) Draw a folder tree for the cloud storage, no more than 4 levels deep. Keep untouched originals apart from edited versions. Write which of your new file names go in which folder.

(b) Why is “final final.jpg” a bad way to show which version is newest? Write one rule that stops anyone overwriting an original photo.

Step 6: who can do what?

Who	No access, view or edit?	Reason
Year 9 pupils
Science teachers
Anyone with the link

Write one check a teacher must make before any image goes into the shared folder.

Step 7: storage and back-up

Use 1 kB = 1000 bytes, 1 MB = 1000 kB and 1 GB = 1000 MB. Show your working.

(a) The camera takes 12 megapixel photos and each pixel needs 3 bytes. How big is one photo before it is compressed, in bytes and in MB? How many times smaller is the 3.6 MB JPEG?

(b) Convert sizes in kB to MB, then find the total size of the files you kept in Step 4.

(c) Use the storage allowance on the fact card. How many MB of JPEG photos will Year 9 take each year? How many full years fit in 2 GB? Would even 1 year fit if the photos were not compressed?

(d) Plan a 3-2-1 back-up.

Copy	Where it is kept	Type of storage	On-site or off-site?
1
2
3

Step by step

4 min Read the stimulus with a partner.
8 min Step 1: total magnification, then find photo G’s missing lens.
10 min Step 2: work out the real sizes and check them against the fact card.
6 min Step 3: design your naming rule.
10 min Step 4: decide about and rename all 10 files.
6 min Step 5: draw the folder tree and write a version rule.
6 min Step 6: set the sharing permissions.
8 min Step 7: storage calculations and the back-up plan.

Success criteria

I can work out total magnification and use magnification = image size ÷ actual size, rearranged when needed, showing my working.
I can convert mm to µm and kB to MB to GB, and check whether an answer is sensible.
My naming rule records sample, magnification, date and group, and I used it the same way for every file I kept.
My folder tree keeps originals apart from edited versions, and my version rule means no original is ever overwritten.
My sharing permissions give each person only the access they need, and no shared image shows a pupil’s face or name.
My back-up plan follows 3-2-1, and my calculations show whether the storage allowance is big enough.

If you finish early

A computer sorts names character by character. Put x40, x100 and x400 in the order a computer would sort them. Change your rule so they sort from lowest to highest.
A new microscope camera takes 48 megapixel photos. How big is one photo before compression?
Write a 3-line version log for photos C and D: file name, date, what changed and who changed it.