Programming · Python
Build a number guessing game in Python
Write a game where the computer picks a number and tells the player "higher" or "lower".
- Beginner
- 1–3 hours
- Free
Weekend projects 91
Start on Saturday, present on Monday: everything here takes a day or less.
Physics · Fluid Mechanics
Build a hydraulic lift with syringes
Connect two syringes of different sizes and show how a small push lifts a large load.
- Easy
- 1 day
- Under 250
Statistics and Probability · Probability
Test the birthday paradox
Calculate and test the chance that two people in a group share a birthday.
- Easy
- 1–3 hours
- Free
Chemistry · Electrochemistry
Build a lemon battery and compare fruits
Make cells from fruit, zinc and copper, measure their voltage and light an LED with several in series.
- Easy
- 1–3 hours
- Under 250
Chemistry · Analytical Chemistry
Make a red cabbage pH indicator and test household liquids
Extract a natural indicator from red cabbage and rank household liquids from acid to base.
- Beginner
- 1–3 hours
- Under 250
Physics · Optics
Measure the speed of light with a chocolate bar
Find the wavelength of microwaves from melt spots on chocolate, then calculate the speed of light.
- Easy
- 1–3 hours
- Under 250
Physics · Mechanics
Calibrate a spring and build a newton meter
Stretch a spring with known weights, plot the graph and turn it into a force meter you can use.
- Beginner
- 1–3 hours
- Under 250
Chemistry + Nutrition and Food
Measure the vitamin C in fruit juices
Titrate juices with iodine and starch to compare how much vitamin C each contains.
- Intermediate
- 1 day
- Under 250
Physics · Optics
Build a pinhole camera and find its magnification
Make a box camera with no lens and show that image size depends on object and screen distance.
- Beginner
- 1–3 hours
- Under 250
Pure Mathematics · Trigonometry
Measure heights with trigonometry
Make a clinometer and find the height of your school building, a tree and a tower.
- Easy
- 1 day
- Under 250
Electrical Engineering + Physics
Build a simple electric motor and measure its speed
Wind a coil motor with a paper-clip cradle and test how turns and magnets change its speed.
- Easy
- 1 day
- Under 250
Physics · Optics
Measure the refractive index of water with a laser pointer
Trace a laser beam entering water at several angles and get the refractive index from Snell's law.
- Intermediate
- 1–3 hours
- Under 250
Statistics and Probability · Probability
Estimate pi by dropping needles
Drop sticks on ruled paper, count how many cross a line and get an estimate of pi.
- Easy
- 1–3 hours
- Free
Biology · Botany
Compare the stomata of different leaves
Take nail-polish peels of leaves and count stomata on upper and lower surfaces.
- Easy
- 1–3 hours
- Under 250
Biology · Cell Biology
Observe osmosis in potato strips
Soak potato strips in salt solutions and find the concentration at which they neither gain nor lose mass.
- Easy
- 1 day
- Under 250
Chemistry · Physical Chemistry
Find how temperature changes reaction rate with antacid tablets
Time how long an effervescent tablet takes to dissolve at different water temperatures.
- Easy
- 1–3 hours
- Under 250
Biology + Sports and Exercise Science
Measure how exercise changes pulse rate and recovery
Record pulse before, during and after exercise for several volunteers and compare recovery times.
- Easy
- 1 day
- Free
Physics · Waves
Measure the speed of sound with two phones
Use two phones with an acoustic stopwatch app to time a clap over a known distance.
- Easy
- 1–3 hours
- Free
Physics · Current Electricity
Verify Ohm's law and find where it fails
Plot current against voltage for a resistor and a bulb and explain the difference.
- Easy
- 1–3 hours
- Under 250
Physics · Electromagnetism
Build a homopolar motor and measure what changes its speed
Make the simplest electric motor from a cell, a magnet and wire, then test how magnets change its speed.
- Easy
- 1–3 hours
- Under 250
Environmental Science + Physics
Compare the energy use of bulbs
Measure the brightness and heat of LED, CFL and filament bulbs and calculate the yearly cost of each.
- Easy
- 1–3 hours
- 250–500
Physics + Environmental Science
Build a solar oven and measure its efficiency
Make a box cooker from cardboard and foil and track how hot it gets compared with open air.
- Easy
- 1 day
- Under 250
Physics · Oscillations
Find g with a simple pendulum and a phone
Time pendulums of different lengths and get the acceleration due to gravity from a straight-line graph.
- Easy
- 1–3 hours
- Under 250
Astronomy and Space + Pure Mathematics
Measure the Earth's circumference like Eratosthenes
Measure a stick's shadow at local noon in two cities and calculate the size of the Earth.
- Intermediate
- 1 day
- Free
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