Biology Measurement Challenge
Age 14 to 16 Challenge Level:
Consider these objects, images for which are given below:
- Mitochondria
- Arabis voch pollen
- Ring stage of Plasmodium falciparum
- Tuberculosis bacterium
- Human red blood cell
- Human nerve cell
- The eye of a needle
- Cat hair
- Snowflake crystal
How many do you recognise? Can you put them in order of length? Cross-sectional area? Volume? Once in order, how many of the smaller objects would fit into the larger objects?
Discussion point: What measurement difficulties does this task raise?
You can see the images, some of which contain scale information, below
Mitochondria

Arabis voch pollen

Ring stage of Plasmodium falciparum

Tuberculosis bacterium

Human red blood cell

Human nerve cell
The eye of a needle
<missing image>
Cat hair

Snowflake Crystal

The URLS of these beautiful images are as follows:
- Mitochondria - https://commons.wikimedia.org/wiki/File:Mitochondria,_mammalian_lung_-_TEM_%282%29.jpg
- Arabis voch Pollen - https://commons.wikimedia.org/wiki/File:Arabis_voch1-1.jpg
- Plasmodium falciparum - https://commons.wikimedia.org/wiki/File:Plasmodium_falciparum_in_Red_Blood_Cells.jpg
- Bacterium (tuberculosis) - https://commons.wikimedia.org/wiki/File:Mycobacterium_tuberculosis_8438_lores.jpg
- Human red blood - https://commons.wikimedia.org/wiki/File:SEM_blood_cells.jpg
- Nerve cell - https://commons.wikimedia.org/wiki/File:Myelinated_neuron.jpg
- Eye of a needle - https://commons.wikimedia.org/wiki/File:Eye_of_a_Needle.jpg
- Cat hair - https://commons.wikimedia.org/wiki/File:ESEM_BSE_cat_hair_No1194_10kV_1000x_680Pa.jpg
- Snow crystals - png: https://commons.wikimedia.org/wiki/File:Snow_crystals.png