IB Physics IA Ideas
That Can Be Completed At Home
1
How does the temperature of water in a wine glass affect the resonant
frequency of sound produced when the wine glass is either struck or a wet
finger runs around the rim and the rim begins to freely vibrate?
Independent Variable: Temperature of Water
Dependent Variable: Resonant Frequency of sound produced
Control Variables: Volume of water, density of glass, cross-sectional area of glass
rim, humidity/temperature of surrounding air
Top Tip - You can use the free SpectrumView app to measure the frequency of sound
produced
2
How does the cross-sectional area of card attached to a vibrating mass affect
the displacement of the mass after twenty oscillations
Independent Variable: Cross-sectional area of damping card
Dependent Variable: Displacement of mass after 20 oscillations
Control Variables: Mass, Initial displacement of oscillating mass, spring constant of
spring, (there's more - I'm sure!)
Top Tip - Set up could look a bit like this...
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3
Investigate the factors affecting the terminal velocity of a paper helicopter
Independent Variable: No. of paperclips OR length of helicopter rotor OR width of
helicopter rotor
Dependent Variable: Terminal velocity of helicopter
Control Variables: Depends on which independent variable you have chosen
Top Tip - Template for model can be found here
4
How does the angle of blade of a toy helicopter affect the lift force on the
helicopter?
Independent Variable: Angle of helicopter blades
Dependent Variable: Lift force of helicopter
Control Variables: Number of helicopter blades, width of helicopter blades,
rotational speed of blades, weight of helicopter (keep going...)
Top Tip - the helicopter should be taped to the electronic scales for this to work
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5
How does the mass of a ball bearing affect the energy loss in a pendulum
system when it is released from 90 degrees and collides with a wall.
Independent Variable: Mass of ball bearing (could choose other variable e.g. angle
of release)
Dependent Variable: Energy loss (calculated using measurements of height of ball
bearing)
Control Variables: Height ball bearing is released, density of ball bearing, density of
wall surface....
Top Tip - the set up could look something like this
6
How the temperature of grease affects the depth of crater created when a
mass is dropped from a known height
Independent Variable: Temperature of grease
Dependent Variable: Depth of crater
Control Variables: mass of ball bearing, height dropped, etc
Top Tip - your personal engagement marks will depend on how you solve the tricky
issues of measuring the depth of the crater.
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7
How does the distance between panes of glass in double glazing affect the
rate of heat loss?
Independent Variable: Distance between two panes of glass
Dependent Variable: Rate of heat loss
Control Variables: outside temperature, inside temperature, thickness of glass,
ambient wind speed, etc.
Top Tip - You should plot a graph of distance between panes on the x-axis and rate of
heat loss on the y-axis.
8
How does the cross-sectional area of the pipe in a siphon affect the volumetric
flow rate of the water in the siphon?
Independent Variable: Cross-sectional area of pipe
Dependent Variable: Volumetric flow rate
Control Variables: height between columns of water, temperature of water, velocity
of water
Top Tip - The equation you should be using is really simple:
Volumetric Flow Rate = (Cross-Sectional Area of the Pipe) x Velocity
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9
How does the height of a ramp affect the time taken for a cylinder to roll down
the ramp?
Independent Variable: Height of ramp
Dependent Variable: Time taken for cylinder to roll down the ramp
Control Variables: Radius of cylinder, length of ramp
Top Tip - when considering the underlying theory, don't forget rotational kinetic
energy!
10
How does the distance between two towers sustaining a flat metallic bar affect
the vertical depression/sag produced when a known mass is added?
Independent Variable: Distance between two towers
Dependent Variable: Depression / sag
Control Variables: mass added, position of mass added, Young modulus of metallic
bar, breadth of metallic bar, depth of metallic bar, temperature of metallic bar
Top Tip - This website gives a good discussion of the physics and the equation you
can use to make your theory / hypothesis. Basically, the sag should be directly
proportional to the cube of distance between the towers.
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11
How does the radius of the exoplanet affect the apparent brightest of a star,
as the exoplanet transits across the star?
Independent Variable: Radius of sphere that mimics the exoplanet
Dependent Variable: Largest Change in Apparent Brightness from the lamp that
mimics the star
Control Variables: Actual brightness of lamp, distance o “exoplanet” from “star, etc
Top Tip - you can model the exoplanet experiment with a set up similar to below. You
can measure light level using iPhone app LuxMeter Pro
Exoplanet Transit
12
Modelling Exoplanet Transit!
How does the length of a violin/guitar string affect the sustain time of the
violin/guitar string after being plucked with a constant force?
Independent Variable: Length of guitar string
Dependent Variable: Sustain time of string after being plucked
Control Variables: force applied to string, temperature of string, humidity and
density of air
Top Tip - You'd need to use an iPhone app to measure sound volume AND make sure
you have a completely silent room. You could try Decibel X PRO: dBA Noise Meter
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