Physics Practical Experiments: Core Investigations

Posted on Aug 8, 2025 in Physics

Specific Heat Capacity Determination

Aim: Determining Specific Heat Capacity

To determine the specific heat capacity (SHC) of a material by measuring temperature changes as energy is transferred.

Equipment for SHC Experiment

  • Block of material (e.g., aluminum or copper) with two holes
  • Heater
  • Thermometer
  • Power supply
  • Ammeter
  • Voltmeter
  • Stopwatch
  • Insulation (e.g., foam)

Method for SHC Measurement

  1. Measure the mass of the metal block (e.g., aluminum or copper).
  2. Insert the heater and thermometer into the block.
  3. Wrap the block in insulation to reduce heat loss.
  4. Connect the circuit: power supply, ammeter, voltmeter, heater.
  5. Record the initial temperature.
  6. Switch on power for a known time (e.g., 10 minutes), record current and voltage.
  7. Monitor and record temperature at regular intervals.
  8. Calculate energy input (E = VIt).
  9. Calculate SHC (c = E / (mΔT)).

Variables in SHC Experiment

  • Independent: Energy input (time or power)
  • Dependent: Temperature of the block
  • Control: Mass of the block, environment, type of insulation, voltage supplied

Thermal Insulation Investigation

Aim: Investigating Thermal Insulation

To investigate how different materials and thicknesses affect the rate of thermal energy transfer from a container of hot water.

Equipment for Thermal Insulation

  • Beaker or identical containers
  • Thermometer
  • Stopwatch
  • Insulating materials (e.g., cotton wool, foil, newspaper)
  • Lid (optional)
  • Hot water

Method: Thermal Insulation Tests

Method A: Comparing Insulating Materials

  1. Fill identical containers with the same volume of hot water.
  2. Wrap each container in a different insulating material.
  3. Record the starting temperature.
  4. Measure temperature every minute for approximately 10 minutes.
  5. Compare the temperature drop for each material to assess insulation effectiveness.

Method B: Varying Insulation Thickness

  1. Use the same insulating material (e.g., newspaper) with different thicknesses.
  2. Repeat the steps from Method A.
  3. Compare the temperature drop for different thicknesses to assess insulation effectiveness.

Variables in Thermal Insulation

  • Independent: Type of insulating material or thickness of insulation
  • Dependent: Temperature change over time / rate of cooling
  • Control: Initial temperature of water, volume of water, size and type of container, use of lid (or not), room temperature

Resistance of a Wire Experiment

Aim: Wire Resistance vs. Length

To investigate how the resistance of a wire depends on its length.

Equipment for Resistance Experiment

  • Power supply
  • Ammeter
  • Voltmeter
  • Ruler
  • Variable length of resistance wire (e.g., nichrome)
  • Crocodile clips
  • Switch

Method: Measuring Wire Resistance

  1. Connect the circuit with the wire mounted on a ruler.
  2. Use crocodile clips to select a specific length of wire.
  3. Record the voltage across the wire and the current through it.
  4. Calculate resistance using Ohm’s Law (R = V/I).
  5. Repeat for different lengths of wire.
  6. Plot a graph of resistance versus length.

Variables in Resistance Experiment

  • Independent: Length of the wire
  • Dependent: Resistance
  • Control: Type of wire, thickness of wire, temperature, voltage supplied

Current-Voltage (I-V) Characteristics

Aim: I-V Characteristics of Components

To investigate the current–voltage (I–V) characteristics of various components:

  • Resistor
  • Filament lamp
  • Diode

Equipment for I-V Characteristics

  • Power supply
  • Ammeter
  • Voltmeter
  • Variable resistor
  • Component (resistor, filament lamp, or diode)
  • Switch
  • Connecting wires

Method: Plotting I-V Graphs

  1. Build the circuit with one component at a time.
  2. Vary the voltage using the variable resistor or power supply.
  3. Record current and voltage for different settings.
  4. Plot I–V graphs (current on y-axis, voltage on x-axis).
  • Resistor: Expect a straight line, indicating an Ohmic conductor.
  • Filament lamp: Expect a curve, as resistance increases when it heats up.
  • Diode: Expect current to flow only in one direction, with a sharp rise after a threshold voltage.

Variables in I-V Characteristics

  • Independent: Voltage
  • Dependent: Current
  • Control: Same component for each test, room temperature, equipment used, measurement technique

Density Determination of Solids & Liquids

Aim: Determining Density of Materials

To determine the densities of regular and irregular solids, and liquids, by calculating mass and volume.

Equipment for Density Measurement

  • Balance
  • Ruler (for regular solids)
  • Measuring cylinder
  • Displacement can (for irregular solids)
  • Water
  • Various objects (regular and irregular solids)
  • Calculator

Method: Density Calculation

For Regular Solids: Density Calculation

  1. Measure dimensions with a ruler (e.g., length, width, height).
  2. Calculate volume using the appropriate formula (e.g., length × width × height for a cuboid).
  3. Measure mass with a balance.
  4. Calculate density using the formula: Density = Mass / Volume.

For Irregular Solids: Density Calculation

  1. Measure mass with a balance.
  2. Use a displacement can or measuring cylinder to find volume:
    • Fill the displacement can to the spout.
    • Carefully lower the irregular solid into the water.
    • Collect the displaced water in a measuring cylinder and record its volume.
  3. Calculate density using the formula: Density = Mass / Volume.

For Liquids: Density Calculation

  1. Zero the balance with the empty measuring cylinder.
  2. Measure the mass of the liquid in the measuring cylinder.
  3. Read the volume of the liquid directly from the measuring cylinder.
  4. Calculate density using the formula: Density = Mass / Volume.

Variables in Density Experiments

Variables for Regular Solids Density

  • Independent: Type of material
  • Dependent: Density
  • Control: Method of measurement, temperature, calibration of measuring equipment

Variables for Irregular Solids Density

  • Independent: Object tested
  • Dependent: Density
  • Control: Volume of water in displacement can, accuracy of balance, water temperature

Variables for Liquid Density

  • Independent: Type of liquid
  • Dependent: Density
  • Control: Volume of liquid, measuring cylinder used, balance calibration