Monday, September 13, 2010




On 25th August as part of our GATE extension programme a group of 12 budding St Albans scientists participated in an exciting workshop at Science Alive –Heat it Up!

The workshop consisted of six stations all focusing on the topic of change. As an introductory exercise students were invited to taste two samples of chocolate-one had been re-set and the other tempered. They then had to compare the properties of the two using taste, touch, smell and appearance.

Everyone made a dough shape which was baked to be used later as a template for a plastic mould into which melted chocolate would be poured. The melting point of chocolate depends on the amount of cocoa butter in the chocolate. Pieces of milk chocolate, white chocolate and dark chocolate were put into test tubes and placed in a water bath. Students had to rank the chocolate in order from lowest melting point to highest melting point.

The second station focused on the boiling point of salt water-is it higher or lower than unsalted water?

At the next station students had to predict what would happen if you added salt to icy cold water and to name a practical application for its use.

The temperature of hot wax was then measured and its melting point predicted. A small mould was filled with the hot wax and the temperature measured again when it began to solidify.

Using dry ice the students looked at sublimation (the change from solid to liquid form) A pellet of dry ice was put into water and the time it took to completely sublimate was recorded.

At the end of the session the pieces of cooked dough were placed in between 2 pieces of polystyrene and subjected to extreme heat so that a mould was formed. Melted chocolate was poured into the mould and of course eventually eaten.

This was a very valuable experience for our students who had previously proved themselves to be very able in the Science area of the curriculum.