Volcanoes

A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur. Gases and rock shoot up through the opening and spill over or fill the air with lava fragments.

There are more than 1500 active volcanoes on the Earth. There are at least 80 under the oceans.

Here are two volcano experiments:

Baking Soda Volcano

Supplies:

· 6 cups of flour

· 2 cups of salt

· 4 tablespoons cooking oil

· 2 tablespoons of baking soda

· dishwashing detergent

· food color

· vinegar

· warm water

· baking dish or pan

Directions:

First, make the cone of the baking soda volcano. Mix 6 cups flour, 2 cups salt, 4 tablespoons cooking oil and 2 cups warm water. The mixture should be smooth and firm. Add more warm water if needed.

Stand the soda bottle in the baking pan and mold the dough around it into a volcano shape.

*Don't cover the opening or drop dough in it.

Fill the bottle most of the way full with warm water and a bit of red food color.

Add 6 drops of detergent to the bottle contents.

Add 2 tablespoons of baking soda to the contents.

Slowly pour vinegar into the bottle and watch the eruption!

EXPLANATION:

Why does this happen? The red lava is the result of a chemical reaction between the baking soda and vinegar. In this reaction, the carbon dioxide gas is produced; pressure builds up inside the plastic bottle until the gas bubbles out of the volcano. This is a good representation of what happens in real volcanoes.

Soda Bottle Volcano

Supplies:

· roll of mint Mentos (type of candy)

· clear 2-liter bottle of Coke (diet works better)

Directions:

Go outside to an area where you have a lot of room. This experiment is messy! Open the bottle of soda carefully. Position the bottle on the ground, so that it will not tip over.

*Diet soda works better than regular soda. Plus, diet doesn't leave a sticky mess.

Unwrap the roll of Mentos. The goal is to drop the Mentos into the bottle at the same time, which is very tricky. One method is to roll a piece of paper into a tube just big enough to hold the loose Mentos. Put a card under the roll and on top of the bottle top, so you can pull the card and the candies will just drop in at once.

Drop all of the Mentos into the bottle at the same time and then move out of the way just as quick as you can and watch the eruption!

EXPLANATION:

Water molecules attract, linking together to form a tight mesh around each bubble of carbon dioxide gas in the soda. When you drop the Mentos in the soda, the gelatin and gum arabic from the dissolving candy break the surface tension. Each Mentos candy has thousands of pits on the surface. These tiny pits are called nucleation sites, perfect places for the carbon dioxide bubbles to form. As soon as you drop the Mentos in the soda, bubbles form all over the surface of the candy. Couple this with the fact that the candies are heavy and sink to the bottom of the bottle and you are just asking for an explosion. When all this gas is released, it literally pushes all the liquid up and out of the bottle in an amazing blast.