Secondary science - Spoonful of knowledge

5th September 2008 at 01:00
What do Donna Summer, a metal spoon, a plastic spoon and a class of eager scientists have in common? Caroline Molyneux's answer is heated debate

The pupils enter the classroom to the sound of "Hot Stuff" by Donna Summer. It's a Year 8 class and they are studying heating and cooling. Today is about conduction, and the difference between things that are good and poor conductors of heat.

On each desk, there is a metal and a plastic spoon. The starter activity on the board reads: "Which spoon is coolest and why?" Pupils have the duration of the song to come up with an answer. The music aids discussion as pupils begin to feel less inhibited.

This question usually prompts the pupils to hold the spoons to their faces. Most groups come to the conclusion that the metal spoon is the coolest. Pupils have difficulty in explaining why, but most can identify that the difference is because of the material that the spoon is made from.

I point out the various thermometers around the room: digital, mercury and even an infra-red laser thermometer that can tell the temperature of objects; all the temperatures are practically the same. How can this be as the metal spoon felt colder?

Pupils then set up their Bunsen burners with clay pipe triangles. We hand out small potatoes in aluminium foil. Half of the class are then given a metal skewer to put through the centre of the potato.

Using tongs to turn their potatoes, we heat them until the skewered potatoes begin to cook. The pupils with the unskewered potatoes find they take up to 10 minutes longer to cook.

We put up a slide on the board with the keywords heat, metal, conducts, passes. Each group must come up with a sentence to explain the class findings.

Following the realisation that the skewered potatoes cooked much quicker than the unskewered ones, pupils of all abilities find it easy to come up with a sentence using these keywords.

Next, using a slideshow of different pictures, pupils must decide if the object is allowing heat to pass through it easily.

They have coloured laminated cards in a pocket on the inside of their books: if they show a green card, then heat passes easily; a red card, not easily. It's a quick way to assess if they can transfer their understanding of the potato experiment to different situations.

We then return to the starter question. Can anyone suggest why the metal feels colder than the plastic? "The metal is taking warmth away from you", and "The plastic doesn't give you any heat" are responses I have had.

Caroline Molyneux is head of science at Balshaw's C of E High School in Leyland, Lancashire.

Make them smile with science

- To make a good lesson summary or revision clips, Windows MovieMaker is simple to use and the impact on the pupils of seeing a lively presentation with music and exciting animation is tremendous. I often ask pupils to make their own.

- Get yourself a free website. Your internet service provider gives you free web space and most have an easy-to-use template. I put weekly lesson topics, homework reminders and news from our science clubs on mine. Visit www.missmolyneux.co.uk.

- Science in the news: Have several plastic wallets up in your classroom and corridor. Each week, print off copies of the science news page from the BBC website and display it in the wallets.

Resources

-www.sparklebox.co.uk has lots of eye-catching science resources.

- www.nhm.ac.uknature-onlinenature-liveindex.html. This links to live lectures and tours of the Natural History Museum website every day at 12.30pm.

- foodsafe.ucdavis. eduindex.html has songs about food and microbes, plus animations for use with the key stage 3 Microbes and Disease topic, among other things.