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Biology experiments and science fair projects

Hands-on biology projects covering plants, microbes, the human body and living systems. Each one lists the exact materials, the time and cost involved, the variables to control and a data table you can fill in — so it works as a class activity or as a full science fair entry.

36 published projects in this collection

Choosing a biology project

Biology projects usually run over days or weeks rather than an afternoon. Plan backwards from your fair date and start early so you can repeat a trial if something goes wrong.

What every project includes

A research question and hypothesis, an independent and dependent variable, the variables you hold constant, a materials list with costs, numbered steps, safety guidance and a reproducibility score based on how completely the method is documented.

Projects to try

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Does the colour of a flower attract more insects?

Set out coloured artificial flower cards outdoors and count insect visits over several days.

Beginner
Elementary +3
1–2 weeks
$10 materials

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Does hand washing time change how clean hands look under a UV tracer?

Apply a UV tracer lotion and photograph hands after different washing times.

Beginner
Elementary +3
1–2 hours
$20 materials

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Does hand sanitiser or soap remove more glitter from hands?

Coat hands in glitter and compare removal by water, sanitiser and soap washing.

Beginner
Elementary +2
30–60 minutes
$5 materials

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Does exposure to hand sanitiser reduce visible microbial growth from surfaces compared to plain water?

Press fingertips onto safe pre-poured agar plates before and after using sanitiser or water, then observe sealed plates for microbial colony growth without opening them.

Challenging
Middle School +2
Several days
$25 materials

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Which sense helps you identify food fastest: smell or sight?

Blindfolded volunteers try to identify foods by smell only, then by sight only, and reaction times are compared.

Beginner
Elementary +2
1 day
$10 materials

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Does light colour affect where woodlice choose to settle?

Place woodlice in a choice chamber with light and dark sides and observe where they settle over time, then return them to their habitat.

Intermediate
Middle School +2
1 day
$5 materials

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Does the amount of sugar affect how much carbon dioxide yeast produces?

Mix yeast with different sugar concentrations in bottles fitted with balloons and measure balloon inflation as an indicator of fermentation rate.

Intermediate
Middle School +2
1 day
$8 materials

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Does soil type affect earthworm movement speed?

Time how long it takes earthworms to burrow through shallow trays of different soil types, then return them safely outdoors.

Intermediate
Elementary +3
1 day
$6 materials

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Does tongue map testing show real differences in taste zone sensitivity?

Apply small taste samples to different tongue regions using cotton swabs and record sensitivity ratings to test the outdated 'tongue map' idea.

Intermediate
Middle School +2
1 day
$8 materials

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Does earlobe attachment show a pattern in families?

Survey and photograph earlobes across several family groups to see how a simple visible trait may follow inheritance patterns.

Beginner
Middle School +2
Several days
No-cost materials

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Do fingerprints patterns run in families?

Collect fingerprint impressions from family members and unrelated volunteers and classify pattern types to compare similarity.

Beginner
Elementary +3
1 day
$5 materials

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Does exercise affect heart rate recovery time?

Measure resting heart rate, exercise heart rate, and recovery time after different intensities of physical activity.

Intermediate
Middle School +2
Several days
$5 materials

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Does the amount of light affect where woodlice or pillbugs gather outdoors?

Survey a garden or outdoor space at different times to count pillbugs found in shaded versus sunlit microhabitats.

Beginner
Elementary +2
Several days
No-cost materials

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Does the type of liquid affect how quickly an eggshell breaks down?

Submerge whole eggs in different liquids and observe daily changes to the shell over several days.

Beginner
Elementary +3
Several days
$6 materials

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Does the type of bread affect how quickly visible mould grows?

Store sealed bread samples of different types in identical conditions and record the day mould first appears.

Intermediate
Middle School +2
1–2 weeks
$8 materials

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Does chewing food more break down starch faster?

Use iodine tests to measure starch breakdown in crackers chewed for different lengths of time, since saliva contains the enzyme amylase.

Intermediate
Middle School +2
1 day
$15 materials

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Does refrigeration slow down fruit browning?

Compare the browning rate of apple slices stored at different temperatures to study enzyme activity.

Beginner
Elementary +3
1 day
$4 materials

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Does the amount of water affect how fast a fruit decomposes?

Observe fruit peel decomposition under dry and moist conditions in sealed containers over two weeks.

Intermediate
Middle School +2
1–2 weeks
$6 materials

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Do birds visit a feeder more at certain times of day?

Observe and record bird visits to a feeder at different times of day over one week without disturbing the birds.

Beginner
Elementary +2
1–2 weeks
$12 materials

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Does seed size affect germination speed?

Plant seeds of varying sizes under identical conditions and record the day each type first sprouts.

Beginner
Elementary +2
1–2 weeks
$7 materials

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Do ants prefer sugary or greasy food?

Place small samples of sugary and greasy food near an ant trail and count how many ants visit each over time.

Beginner
Elementary +2
1 day
$3 materials

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Does the amount of light change how many stomata a leaf opens?

Take clear-tape impressions of leaf surfaces from sun and shade plants and compare counts under magnification.

Challenging
Middle School +2
Several days
$12 materials

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Does hand dominance affect grip strength and accuracy?

Measure timed peg placement and steadiness for both hands across many volunteers.

Beginner
Elementary +3
Several days
$10 materials

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Does mouthwash change how quickly bread mould appears?

Treat sealed bread samples with different liquids and photograph mould growth over ten days.

Intermediate
Middle School +2
1–2 weeks
$12 materials

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Preparing for a fair? Read the science fair guide or record your data in the lab.