Energy changes and transfers
The demonstrations and investigations allow students to explore energy changes and transfers through practical activities.
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
Find out if you could be a Kung Fu expert. This is a great idea for a practical lesson. By dropping masses, students first find out the energy required to break a board. They then work out whether their moving hand has enough energy to match or exceed this – if so then, theoretically at least, they could break the board with their bare hand.
It’s a very engaging lesson and there's physics developed along the way, including plenty of opportunities for calculations. What's not to like?
Practical tips: Instead of a ticker timer, students could measure the speed of their hand directly using a light gate. Get them to hold a piece of black card vertically in their hand and then pass it through the sensor as quickly as possible. They can measure the width of the card more easily than they can measure the width of their hand, and if the card should happen to hit the sensor it will do less damage (and hurt less!) than a hand.
If you wanted to measure the mass of student’s hands more directly it could be done by displacing water in a Eureka can (1cm3 of water = 1g)
Actually breaking the board would make a memorable end to the lesson – any black belts out there prepared to give it a go?
This dramatic demonstration shows how mechanical work can be used to produce heat energy, in fact enough energy to start a fire. Following on from a lesson about work, challenge students to see if they can explain how it works.
Teachers will find the two explanations given very useful and they could use either or both with their students depending on ability and age.
Fire pistons are available to purchase from the usual scientific suppliers if your school doesn’t have one. Alternatively, you will find instructions for building your own via an internet search engine.
Most students will tell you that heat energy travels from hot places to cold places. This simple yet profound demonstration will challenge them to think more deeply about this simple concept since the block that feels colder melts the ice more quickly.
This demonstration is a good opportunity for teachers to use plenty of open questions to guide students thinking and to develop scientific vocabulary.
This is a comprehensive package of resources from the Science Enhancement Project (SEP) designed to support teachers through the whole topic of energy. It provides an excellent model for the concept of energy and uses energy meters to make the concept more concrete for students. The SEP energy meter is available at reasonable cost from Mindsets : http://www.mindsetsonline.co.uk/product_info.php?products_id=1398, as indeed is all the equipment referred to in the booklet.
The first student activity, A1 Getting to Know the Joule, provides a good foundation for all the work that follows and includes some useful graphical work. Teachers should note that the concept of power (activity A2) is not included in the keystage three curriculum.
Activities B1 and B2 involve measuring the energy consumption of household objects and are recommended. All the activities are supported by student worksheets, presentations. Some activities have accompanying spread sheets which teachers will find useful, by typing in different figures, students will be able to see, for example the costs of running different appliances or the savings made by turning machines off standby.
Those teaching outside of their specialism will appreciate the overview of the topic provided at the front of the booklet.
A further set of presentations and animations which support this work are to be found in the resource below.
This resource uses dye as a model for energy. There are some good ideas for practical work and a set of animations which will aid explanations. Even if you don’t use the suggested practical work, the animations could be used to support the teaching of energy transfers in any lesson and would be helpful in conjunction with the resource above.
This resource, originally developed for keystage four students, has been adapted for students working at levels 3-6 which makes it accessible for students in keystage three.
Where Does All the Energy Go? (page 32 of the pdf document) is a particularly good piece of experimental work for encouraging students to think about energy transfers. A beaker of hot water is placed in a beaker or bowl of cold water and the temperatures of both are monitored over time. Where does the heat energy in the hot water go? The temperature drop of the hot water will not match the temperature rise of the cold water, why not? Has one lost more energy than the other has gained?
The student sheets are clear and useful though teacher might prefer graphs to be drawn on graph paper rather than on the grid provided.
Activity one from this booklet would make a good introductory lesson to this topic. A whole series of mini experiments are undertaken with the aim of finding out what connects them all.
However, the resource is a little dated and now the experiments are probably best carried out as whole class activities with volunteer students making the measurements etc. If the teacher gives instructions, there is no needed for a printed student instruction sheet. The teacher can also oversee the health and safety aspects satisfactorily and lead/prompt student discussion and questions. To preserve the "mystery" of what connects them all, teachers should be careful not to use the word “energy”
The follow up work uses money as a good analogy for energy. However, the worksheet is likely need re-writing to bring it up to date –it’s probably not a good idea to refer to housewives these days!
Lift one of your students with just one hand! Here’s a whole set of resources from the Institute of Physics (IOP) on the topic of levers specifically designed for keystage three students. After you have downloaded the file choose Ma01: TA to find the teaching approaches you might take. Background notes can be found in Ma01 PN and Ma01 PL and will be particularly appreciated by those teaching outside of their specialism.
As you might expect from the IOP, this is a well thought out scheme which develops and challenges student’s ideas as it is worked through