Pick Up an Ice Cube with a String

Pour salt over ice cube and string

Pour salt over ice cube and string

Materials
Full cup of water
Ice cube
Salt
~12 inches of string

Procedure
Put your ice cube in your cup of water.
Drape your piece of string across the ice cube; make sure there are a few inches of slack on each side.
Pour salt on top of the ice cube and string.
Wait for 60 seconds, then, taking the ends of the string in each hand, slowly lift the ice cube out of the water.

Results

Carefully lift ice cube

Carefully lift ice cube

You’ve picked up an ice cube using just a piece of string! How? According to explorable.com, the addition of the salt disrupts the state of equilibrium that existed between the ice cube and the water. The salt molecules begin to dissolve and mix with the water molecules; this changes the water’s rate of freezing. The rate of melting is now far quicker than the rate of freezing, causing the ice to melt rapidly. In order to restore the state of equilibrium, the water’s freezing point drops, causing the ice to freeze. The salt begins crystallizing and the ice ultimately refreezes around the string.

Fall Leaf Chromatography

Materials - Fresh Green Leaves

Materials: Fresh Green Leaves

Materials:
Variety of freshly plucked leaves
Clear plastic cups, jars or glasses
Rubbing alcohol
Plastic wrap
Pencil
String
Coffee filters

Procedure: Place Torn Leaves in Individual Jars

Procedure: Place Torn Leaves in Jars

Procedure:
1. Collect some green leaves from multiple trees.
2. Tear up each leaf and place the pieces in a cup (one leaf per cup).
3. Add just enough rubbing alcohol to cover the leaf bits and cover with plastic wrap.
4. Allow the cup to sit for about 30 minutes.
5. Tie a piece of coffee filter to a pencil and place the pencil over the cup, allowing the coffee filter to dangle and just touch the top of the liquid.
6. Let the coffee filter sit for an hour or two.
7. Compare your results.

Procedure: Allow Experiment To Sit

Procedure: Allow Experiment To Sit


What Happened and Why?

As the liquid traveled up the coffee filter, you probably noticed a separation of colors. More than likely, you observed varying shades of green and maybe even some red, orange and yellow areas.

Results

Results

Leaves appear green because of a pigment called chlorophyll, which is necessary for photosynthesis. Chlorophyll can often cover up other pigments, though. When fall arrives and the leaves begin to change, chlorophyll breaks down, allowing you to see the red, yellow and orange pigments contained within the leaves. In the experiment above, you were able to see these hidden pigments on the coffee filter. Use these results to guess which trees will be most colorful in the fall!