Step 12 of 18 · Cells and classification · SC4-CLS-01 · SC4-WS-01
Microscopes
Multiply the lenses. Start on low power. Divide the view by the cells.
Learn it
Use a light microscope correctly, and calculate magnification and cell size
Idea 1 of 4
Total magnification
Multiply the eyepiece by the objective lens. A 10× eyepiece with a 40× objective gives 400× — the image is 400 times bigger than the real thing.
Know it by heart
Say each one in your head, then tap to check.
Try it
Play — nothing here is marked
Tap any part · drag the focus knobs · spin it round
How to use a microscope
Step 1 of 8: Carry it safely
Do it: Tap the arm, then the base.
- 1Carry it safelyOne hand on the arm, one under the base, so it can't swing or fall.
- 2Turn on the light
- 3Start on the lowest power
- 4Put the slide on and clip it
- 5Raise the stage, watching from the side
- 6Focus by lowering the stage
- 7Sharpen with the fine focus
- 8Switch to high power
Estimate a cell's length
On 40× the field of view is 0.45 mm across. Count the cells across the middle of the eyepiece view.
0.45 mm ÷ 6 = 75 µm
A full-marks answer
The field of view at 100× is 1.6 mm. Eight cells fit across it. Estimate the size of one cell in micrometres.
3 marksBuilt one line at a time — say the next line before you reveal it
- Cell size = field of view ÷ number of cells(formula)
Words to know
Tap a card to flip it
Step 12 · last bit
Ready? Prove it.
A round of ten. Score 8 or more and this step is done — then on to specialised cells.