Diffusion
This list provides a range of activities and demonstrations, together with background information and suggested teaching strategies, which explore diffusion. The use of models and analogies here can aid understanding and students should be challenged to use a simple particle model to explain what they observe.
The resources link to the following topics:
- diffusion in terms of the particle model
- diffusion in liquids and gases driven by differences in concentration
- Brownian motion in gases
Visit the secondary science webpage to access all lists: www.nationalstemcentre.org.uk/secondaryscience
Whilst this list provides a source of information and ideas for experimental work, it is important to note that recommendations can date very quickly. Do NOT follow suggestions which conflict with current advice from CLEAPSS, SSERC or recent safety guides. eLibrary users are responsible for ensuring that any activity, including practical work, which they carry out is consistent with current regulations related to health and safety and that they carry an appropriate risk assessment. Further information is provided in our Health and Safety guidance.
Particles
Although slightly dated, this pupil book and teacher guide has some really well explained theory and good practicals that fit in with this topic. Each chapter also has a series of good written activities that could be taken and re-purposed in a more up to date way.
Perfumes and Smelling
This is a really good set of activities based around perfumes. There are instructions for a perfume circus activity which would make a good starter activity and also for two different ways of making perfume as class practicals. There are full teacher and technician notes and a set of student worksheets.
Diffusion with jelly cubes
In this experiment, students can investigate diffusion by placing agar cubes of varying sizes in acid and observing the colour change. The webpage contains full teacher and technician notes.
Diffusion in liquids
In this experiment, students place colourless crystals of lead nitrate and potassium iodide at opposite sides of a Petri dish of de-ionised water. As these substances dissolve and diffuse towards each other, students can observe clouds of yellow lead iodide forming, demonstrating that diffusion has taken place.
Brownian Motion
This video shows how to show the movement of particles by Brownian motion. Instead of using the traditional smoke cell, the video shows how Brownian motion can be observed in a suspension containing micrometre diameter polystyrene spheres. Using a microscope and video camera, students can observe the motion of the polystyrene spheres. The video also shows how Brownian motion can be simulated using a vibrating loudspeaker, table tennis balls and a small balloon.
