– Define density as mass per unit volume and recall the equation: ρ=mV\rho = \frac{m}{V}.
Activities
– Starter (5 mins): Ask students: “Why do some objects float while others sink?” Introduce the concept of density.- Main (25 mins): 1. Defining Density: Explain the formula ρ=mV\rho = \frac{m}{V}. 2. Example Calculations: Demonstrate calculating the density of a solid object. 3. Class Practice: Students calculate the density of a given object using provided data.- Plenary (10 mins): Review key points and discuss why density is an important physical quantity.
Resources
Mass and volume data for objects, calculator, whiteboard.
Time
40 minutes (5 mins Starter + 25 mins Main + 10 mins Plenary).
Homework
Find the density of a common household item (e.g., a coin or a marble) using its mass and volume.
Assessment
Students solve density calculation questions in class and provide answers for feedback.
Past Paper Practice
IGCSE Physics 0625/22/O/N/18 Q4(a).
Lesson 2: Determining Density of Regular and Irregular Objects
Section
Details
Objective
– Describe how to determine the density of regular solids, liquids, and irregular solids.
Activities
– Starter (5 mins): Recap the formula for density and introduce the concept of determining volume using displacement for irregular objects.- Main (25 mins): 1. Regular Solids: Demonstrate measuring mass using a balance and volume using geometric formulae (e.g., V=l×b×hV = l \times b \times h). 2. Liquids: Measure the mass of a liquid by subtracting the container’s mass and determine its volume using a measuring cylinder. 3. Irregular Solids: Use a displacement can to measure the volume of irregular objects.- Plenary (10 mins): Summarize the methods and discuss possible errors.
Resources
Displacement can, balance, measuring cylinder, regular and irregular objects, water.
Time
40 minutes (5 mins Starter + 25 mins Main + 10 mins Plenary).
Homework
Perform the displacement method for an irregular object at home and calculate its density.
Assessment
Students measure the density of an object during the practical activity and present their results.
Past Paper Practice
IGCSE Physics 0625/12/M/J/20 Q2(c).
Lesson 3: Floating and Sinking Based on Density
Section
Details
Objective
– Determine whether an object floats or sinks based on its density relative to the liquid.
Activities
– Starter (5 mins): Ask: “Why do ships float while a solid metal block sinks?” Introduce the principle of density and buoyancy.- Main (25 mins): 1. Floating and Sinking: Explain the relationship between density and buoyant force. 2. Practical Experiment: Provide objects of different densities and demonstrate floating and sinking in water. 3. Discussion: Relate the concept to real-world examples (e.g., icebergs, oil spills).- Plenary (10 mins): Review the conditions for floating and sinking.
Resources
Beakers, water, objects with varying densities (wood, metal, plastic).
Time
40 minutes (5 mins Starter + 25 mins Main + 10 mins Plenary).
Homework
List 5 objects at home that float and 5 that sink in water. Try to explain why.
Assessment
Students predict and test whether provided objects will float or sink, based on their densities.
Past Paper Practice
IGCSE Physics 0625/21/M/J/19 Q3(b).
Key Notes for Students:
Density Basics:
Remember the formula ρ=mV\rho = \frac{m}{V}.
Use consistent units for mass (kg or g) and volume (m3\text{m}^3 or cm3\text{cm}^3).
Practical Accuracy:
Avoid parallax errors when reading volumes.
Always ensure the object is fully submerged when using the displacement method.
Key Notes for Teachers:
Demonstration Importance:
Clearly show each step in density calculations, especially for irregular objects.
Common Errors to Address:
Misreading scales on balances or cylinders.
Forgetting to subtract the container’s mass when measuring liquids.
Leave a Reply