Science Week, Our First Day

The girls both love doing experiments but sadly when I am in a hurry they often get set aside to do later and sometimes that never happens. This week I decided to concentrate on doing a simple experiment or two a day.

I noticed there was a Brownie patch called "Science Wizz" in Agent Smelly's Brownie book so we decided to do those experiments so she could earn herself a Brownie patch.


The first experiment we did was called "The Magic Balloon".

You will need

• a glass bottle
• a balloon with the thick rubber ring cut off the neck
• water
• large bowl or saucepan to stand the bottle in
• ice cubes (optional but the greater the temperature difference between the hot and cold water the better the experiment will work)

   
1. Fill a glass bottle with hot tap water and let it sit for a couple of minutes before tipping it outand then quickly stretch the neck of the balloon over the bottle; check out the concentration on those faces.

Place bottle in the bowl of cold (iced) water and wait and wait.

What happens to the balloon when you stand the bottle in the cold water?

 

It gets sucked into the bottle. Success! 

Why did this happen? Well when hot water is added to the empty bottle it begins to heat the glass. After the bottle is emptied, the warm glass heats the air inside of it. The heat causes the air molecules inside the bottle to move more rapidly and pushes them further apart from each other. The air in the bottle expands and inflates the balloon. When the bottle is placed into the bowl of cold water, the air inside the bottle is cooled. This causes the air molecules to move slower and closer together. The air contracts and causes the outside air to rush in. This pulls the balloon inside the bottle and inflates it. Ours didn't really inflate that well but the girls were happy with watching it get sucked into the bottle.


Next we did "Pepper Away".

You will need

• pepper
• a bowl filled with water
• toothpicks
• dishwashing liquid

1. Sprinkle some pepper into a bowl with water in it. Most of the pepper will float on the water. Dip a toothpick into the water and you will see nothing happens.

 

 

2. Dip a toothpick into some dishwashing liquid then dip the toothpick into the water again and voila! In the wods of Agent Smelly the pepper "retreated from the toothpicks. (They were in the middle, they just moved them to the sides to see the pepper move again).

 

When you add detergent to the water the surface tension of the water is lowered. Water normally blulges up a bit, but when the water flattens because of the detergent, the pepper that is floating on the top of the water is carried to the outside of the bowl as though by magic.