Term 2 Week 6

Room 21’s Week 6 Wrap Up

The weather gods sort of looked after us on Tuesday for our Ports of Auckland Harbour Cruise. The seas were relatively calm and when it does occasionally rain, we just sort shelter inside the ferry...well, some of us did...for others, the rain was all part of the adventure! J It was a wonderful cruise around the harbour, highlights including the huge container ships loading and unloading cargo, the Westhaven Marina and getting up close to the super yachts and going under the Auckland Harbour Bridge.

Science this week got all mysterious...I’m sure you’ve heard of secret messages written in code, but have you heard of secret messages being written in invisible ink? This week’s chemistry experiment involved us writing a secret invisible ink letter to a friend. It’s quite simple and one you can easily try at home. First, squeeze the juice of a lemon into a saucer and then add a few drops of water and mix well with a spoon. Now dip a toothpick into the lemon juice (but careful, not too much as you’ll end up with invisible blobs!). Use the toothpick to write a message on ordinary white paper (thick paper seems to work best). When it dries the writing will be invisible. Heat the paper by holding it with written side down near a light bulb. If an adult us helping you, you might be able to use the heat from a stove or a candle. So what is happening??? While it heats up the invisible ink writing slowly becomes brown and visible and the words appear on the page. So why is this happening??? The juice of the lemon has compounds of carbon. These compounds have almost no colour when they dissolve in water. When you heat them, the carbon compounds break down and turn black.