Invisible Ink

Ever wanted to be a spy when you were a kid? Ever wanted to talk or write to your friends but never wanted your brother and sister to know what you said or wrote? Here is a really easy way to make some invisible ink so that your kids can do just that.

Supplies:
Lemons (or pure lemon juice)
cotton swabs (q-tips)
paper

In a small bowl, squeeze a couple of lemons taking out any seeds (you can also use bottled pure lemon juice). Using the cotton swabs, draw a fun picture on your paper. Let dry completely.

Using a heat source (like a lamp that has been on for a while, or a toaster or hair dryer) reveal the "secret" message/picture.

The heat turns the lemon juice a dark brown color.

Oobleck with a Book

There is always the OOBLECK experiment to read with the book Bartholomew & the Oobleck by Dr. Seuss (here is a link to the book: http://www.amazon.com/Bartholomew-Oobleck-Caldecott-Honor-Classic/dp/0394800753). The Dr. Seuss book talks about Bartholomew and how he is attacked by a big sticky glob of oobleck.

Supplies:
Cornstarch
water
green food coloring

To make Oobleck you simply mix corn starch and water together until it is runny when you pour it but solid when you try to stir or pick it up. Add a few drops of green food coloring to go with the story. It is pretty cool because it is a solid and liquid at the same time. You can pick it up and then if you leave it flat it will puddle like water.

This experiment is a great way to introduce kids to science. You can talk about solids and liquids and the differences and how this is one instance where something can be a solid and liquid at the same time. There are also videos on YouTube where people have made a giant bathtub filled with "oobleck" and actually run across it (also featured on the TV Show Numb3rs Season 4 Episode 16).