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Monday, August 16, 2010

What do hokey pokey and pumice have in common?

Well - quite a lot actually!

On Friday at Science Club we made hokey pokey.

First we had to measure out the sugar and golden syrup into a saucepan.

This mixture then had to boil for 7 minutes.

After 7 minutes the baking soda was stirred in. Suddenly the golden liquid when lighter and puffed up. When the baking soda was added to the hot mixture the reaction that occurred produced a gas that made the hokey pokey mixture expand and puff up.

The hokey pokey was then spread on a tray to cool and set.

When the hokey pokey was cut up we could see that there were lots of tiny holes inside.

Next we looked at different rocks and discovered that hokey pokey looked and felt a lot like pumice. They both had small holes and were really light.

Pumice is a type of rock that is produced in volcanoes. Miss Harrison challenged us to think about how the pumice might be made. After thinking for a while we came up with this explanation.

When a volcano erupts lava comes out of the volcano. At the same time there is a lot of gas coming out of the volcano. The gas mixes with the lava and makes it puff up (just like the baking soda did in the hokey pokey mixture) to produce the light and air filled pumice.

I wonder if we are right.

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