Observing cells and tissues
The practical acitivities listed here allow students to become familiar with using a microscope to observe a variety of cells.
Visit the practical work page to access all resources and lists focussing on practical work in secondary science: www.nationalstemcentre.org.uk/sciencepracticals
Links and Resources
This resource provides ideas for developing a sequence of 'good enough' cell models to explore how cells can form tissues and organs.
Modelling a simple animal and plant cell can be done as a demonstration intitially, discussing what each part of the model represents and relating it to what can be seen under the microscope. The image from the microscope could be projected onto a white board using a webcam.
Students can then create their own models of simple and specialised cells. When modelling cells, discussing the strengths and weaknesses of the model can draw out misconceptions. For example, having viewed cells as images or under a microscope, students can easily believe that they are two-dimensional.
Carefully planned group work with explicit aims can encourage students to relate structure to function, extending the activity to allow connections to be made between between the practical work and scientific ideas.
The cards in activity 5 (page 20) of this resource can be used to extend students' observations of euglena by considering whether euglena are plant or animal cells.
Students evaluate their own observations and the evidence presented on the cards to support their point of view about euglena. Since some of the evidence can be ambiguous and could indicate that euglena is both an animal cell and a plant cell (e.g. it moves and it has chlorophyll), the activity provides an opportunity to generate cognitive conflict for students.