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Topic: 6G Changing circuits
Rentokil has developed traps that send you an email when they make a catch. It takes pressure measurements to distinguish between vermin and family pets, and it kills quickly and humanely by releasing carbon dioxide gas.
In this activity the children are challenged to design electrical circuits that would alert the user in different ways when an object or animal is sensed.
An Upd8 task designed for CCEA (Northern Ireland) in line with the Revised Curriculum requirements for the World Around Us and Thinking Skills & Personal Capabilities.
You will need Acrobat
Reader installed to open the activity sheets.
You will also need the latest version of the flash player to be able to play swf files.
· to construct circuits, incorporating a battery or power supply and a range of switches, to make electrical devices work
Children will demonstrate this by completing the task on Page 1 successfully
· how changing the number or type of components in a series circuit can make bulbs brighter or dimmer
Children will demonstrate this by completing the task on Page 3 successfully
· how to represent series circuits by drawings and conventional symbols, and how to construct series circuits on the basis of drawings and diagrams using conventional symbols
Children will demonstrate this by completing the tasks on Page 1 and 3 successfully
Science:
Unit 6G: Changing Circuits
· that the brightness of bulbs in a circuit can be changed
· that there are conventional symbols for components in circuits and these can be used to draw diagrams of circuits
Scientific enquiry
Ideas and evidence
· Describe how experimental evidence and creative thinking have combined to provide a scientific explanation
· Support a prediction with evidence
· Begin to identify whether given conclusions are sufficiently supported by evidence
Considering evidence and evaluating
· Offer simple explanations
· Draw conclusions that are consistent with the evidence and begin to relate these to scientific knowledge and understanding
Introducing the activity
· Display page 1 through a projector or as an OHT. Read through the introductory paragraph. Ask the questions:
- What advantages might this new type of trap have over old ones?
- How would the different parts of the trap be connected to make a circuit?
Set the task to draw a suitable circuit diagram using the symbols shown.
Leading the main activity
· Display page 2 through a projector or as an OHT. Ask the children to discuss in pairs or small teams which of the rats they agree with. Encourage the children to justify their opinions. This discussion could be extended by asking the children to investigate practically the position of a switch in a simple circuit.
Discussion starters for this task:
When the children are considering the position of the switch in the circuit:
§ What do you think electricity is like?
§ What do we mean by an electrical circuit?
§ What is needed for an electrical circuit to work?
§ How does a switch work?
· Display page 3 through a projector or as an OHT. Print off copies for children as necessary. Ask the children to consider how the trap circuit could be modified.
Discussion starters for this task:
When the children are modifying the original circuit:
§ How would you connect a bulb and buzzer into the circuit?
§ Why would extra batteries make the bulb brighter and buzzer louder?
§ What would happen if there were too many batteries?
Ask the children how a new device could be designed incorporating an electrical circuit.
Discussion starters for this task:
When the children are designing circuits for their invention:
§ How is a circuit diagram different to a picture?
§ How could putting more components in a circuit affect it?
§ What is the electricity being used for in your invention?
There are no specific solutions for the second task. However, in both tasks try to find out what the children know and think about the way electricity flows. Depending on the ability of your children, challenge them to describe what is happening regarding the flow of electricity through the circuit. Encourage them to use diagrams, metaphors or models to help them explain.
Extension Ideas
Pressure switches can also used in burglar alarms. They can be hidden under carpets or door mats. When the burglar steps on the switch the circuit is completed and the alarm goes off. Try designing, making and testing your own pressure switch. The following materials could be useful: large paper clips, brass paper fasteners, thick cardboard, rubber bands, pieces of sponge, aluminum foil
Revisewise Science
Electricity activity using ICT resource to learn about circuits
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