HKDSE Physics case studies
HKDSE Physics · Put your knowledge to work in context.
HKDSE Physics is a Category A Senior Secondary elective in the Hong Kong Diploma of Secondary Education, administered by the Hong Kong Examinations and Assessment Authority (HKEAA). It is taken by Secondary 6 candidates in Hong Kong schools, and by private candidates, who need a physics result for university admission, especially for engineering, physical sciences, and health-related programmes. The HKDSE Physics case studies are 5 cases and about 4,707 words.
1The Trolley That Accelerates Too Slowly: Where Did 0.13 N Go?
In a school laboratory a group sets up a 1.20 m dynamics runway with a pulley at the raised end. To compensate for friction they slip a 2 mm card under one leg, give the trolley a gentle push, and judge by eye that it keeps a steady speed.
992 words, about 5 min2The Specific Heat That Keeps Coming Out Too High
To measure the specific heat capacity of aluminium, a student uses a 1.00 kg block with two drilled holes, one for a 30 W heater (12 V, 2.5 A) and one for a thermometer. Run 1: starting at 20.0 °C, the heater runs for 300 s; the thermometer reads 28.5 °C at switch-off and peaks at 28.9 °C half a minute later, giving c = 9000/(1.00 × 8.5) ≈ 1060 J kg⁻¹ K⁻¹.
956 words, about 5 min3Three Resonances and a Two-and-a-Half Per Cent Discrepancy
A student measures the speed of sound using a vertical plastic tube whose lower end is closed by a movable water surface, and a loudspeaker driven by a signal generator set to 512 Hz and held just above the open top. Moving the water level, she finds three successive loudest positions at 16.4 cm, 50.1 cm and 83.8 cm above the water.
900 words, about 5 min4Two Students, Two Voltmeters, Two Internal Resistances
Two students measure the emf and internal resistance of the same new 1.5 V alkaline cell. Student A connects the cell, an ammeter (resistance about 0.10 Ω) and a variable resistor in series, and a digital voltmeter across the cell's terminals; she reads 0.142 A at 1.44 V and 0.600 A at 1.26 V.
964 words, about 5 min5Dating a Beam: Varnish, Logarithms and a Confident Curator
A museum sends a school laboratory a slice cut from the inner part of an old wooden beam and asks for a date. A technician counts the sample overnight, using the same geometry as for a modern wood standard, and obtains a specific activity of 0.190 Bq per gram of carbon.
895 words, about 4 min