Wednesday, May 9, 2012

Science Week; Day 3

Today was a bit of "Harry Potter" day ... magic potions and invisible ink.

"Magic Potion"

You will need
cauldron (medium sized container)
baking soda

1. Place 2 tablespoons of water in the container and stir in a tablespoon of baking soda until it dissolves.

2. Have 2 tablespoons on vinegar ready in a separate cup and then pour it into the container all at once and watch what happens.

I then explained that what appeared to be one reaction was actually two, happening in quick succession. The acetic acid in the vinegar reacts with the sodium bicarbonate (in the baking soda) to form carbonic acid. Carbonic acid is unstable, and it immediately falls apart into carbon dioxide and water. The bubbles they could see from the reaction came from the carbon dioxide escaping from the leftover solution.

This is such a simple and popular experiment but still my girls nearly 8 and 10 were excited at the outcome. A reminder to me to still do experiments that they may have already performed when they were younger as they tend to understand and notice more as they get older.

"Invisible Ink"

You will need
  • lemon juice from a lemon
  • toothpick or small stick
  • piece of plain paper
  • iron
1. Squeeze the juice out of a lemon onto a saucer.

2. Dip your toothpick (or small stick) into the juice and use it to write a secret message on a piece of paper. When the "ink" is dry the words disappear.

3. To see the message again, all you do is iron the paper. I closely supervised the girls with the iron so would recommend an adult do this bit if your child is not familiar with an iron.

I was not allowed to photograph their messages as they were "secret"!

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