Recycling Paper With Science

This week, I thought you might want to explore a little science related to the conservation and environmental science. Grab your kids, some old newspaper, and a pair of used pantyhose.  It’s time to make some recycled paper!

Here’s What You Need

• a food processor or an old blender
• an old wire hanger
• an old pair of panty hose
• newspaper or other paper, torn into 2-inch squares
• white glue (e.g. Elmer’s glue)
• Tablespoon
• Large flat bottom container (a little wider that the sheet of paper you want to make)
• Water
• food coloring or brown/red onion peels (optional)

Here’s What You Do

First, let’s make the frame for our sheet of recycled paper.  Stretch the hanger and bend it into a rectangle/square shape. Take one leg of the panty hose and stretch it carefully over the hanger frame. Make sure it is tight and flat. When you are done, you should have something that resembles a tennis racket!

Next, let’s make our pulp mixture. Put a handful of the torn newspaper and some water into the food processor or blender. Blend the mixture on high until it becomes mushy. Keep adding paper and water until you have a big gray blob of mush. You may have to add a little more water to keep things moving smoothly. Keep the food processor on until all the bits of paper have disappeared. If you want to add a little color to your paper, add a handful of brown or red onion skin (not the onion itself, just the papery outer skin) or a few drops of food coloring.

Add about 4 inches of room temperature water to your flat bottom container. Scoop out about your blog of mush and mix it into the water.  Add 2 tablespoons of white glue into water and mush mixture.  Now, carefully mix it with your hands.

Time to make some paper!  Carefully, place your pantyhose covered hanger on the bottom of the flat bottom container filled with the water and mush mixture.  Make sure you have plenty of the mush floating around above the hanger. Now, slowly lift the hanger out of the water.  Make sure you keep in horizontal as you lift it.  The slower you lift the thicker your paper will be.  After you lift the hanger completely out of the water, hold it over the container to let the excess water drain out for about a minute. You should see a thin layer of the gray mush covering the pantyhose on the hanger.  Don’t touch it!  It is very fragile at this point.

Lay the mush covered hanger flat in the sun or in a window sill. It will take a while to dry. Depending on the temperature and the amount of sun, your paper could take anywhere from a couple of hours to an entire day to dry.  Keep checking it from time to time.  When it looks like it is completely dry, you can carefully peel your sheet of paper off of the pantyhose.  Congratulations, you just made your first piece of recycled paper!

The Science Behind The Paper

Recycling is the process of taking a used item and breaking them down to create a new product. In this activity, you took newspaper, broke it down, and made a new sheet of recycled paper. Paper is made from a natural material called cellulose.  This special material is found in the cell wall of many plant cells. Long ago, people figured out how to get the cellulose out of wood and use it to make paper. Often, paper is made from pine trees. One pine tree produces about 8,000 sheets of paper.  However, it is estimated that we use about 71 trillion tons of paper each year.  That’s a lot of paper and a lot of trees. In order to conserve the number of trees used in making paper, some people have figured out how to recover the cellulose needed to make paper from used paper.  Today, about one third of the paper we use is recycled or contains recycled cellulose.
 
In this activity, you used the blender or food processor to separate the newspaper into individual strands of cellulose.  When you placed the blob of mush in the water, these fibers began to float around. If you would have tried to make paper with this mixture, it would have result in brittle paper because the cellulose fibers aren’t really great about sticking to each other without a little help.  That’s why we added a little glue to the mix.  It helps the individual fibers of cellulose to stick to each other and makes the final piece of paper much stronger!

Use Science to Make a Naked Egg

You've fried them.  You've scramble them.  You've boiled them.  Chances are that you even painted and hunted for them.  The question is...have you ever striped one?  That's right, in this activity, you will create your very own naked egg!

Here's What You Need

• Cup or jar large enough to hold the egg
• Vinegar
• Egg

Here's What You Do
Gently place the eggs in the cup/jar. Pour enough vinegar into the cup/jar to cover the egg.  Take a couple of minutes to observe what happens to the egg as it sits in the vinegar.  You might notice bubbles forming on the outside of the egg.  We'll talk about that a bit later.  For now, place the cup/jar somewhere out of the way and let it sit for about 24 hours.

You will see bubbles forming on the egg shortly after pouring in the vinegar.

After 24 hours, carefully remove the egg from the vinegar.  You might need a large spoon.  Make sure you are very careful.  The egg will be very fragile at this point.  Pour the vinegar out of the cup/jar.  Gently place the egg back in the cup/jar, cover it with fresh vinegar, and put it somewhere safe for another 24 hours. 


Use your hand or a spoon to carefully remove the egg from the vinegar.  Rinse them with water.  You should now have an egg without a shell!  You will notice that the eggs shell is gone.  Instead, a thin membrane is all that is left surrounding the egg white and yolk.  It is translucent and flexes when you squeeze it!  Congratulations!  You have successfully created a naked egg!

Once the shell is gone, you will be able to squeeze the egg easily between your fingers.

The Science Behind the Naked Egg

Of course, there is a lot of science behind the naked egg.  For example, when you poured the vinegar over the egg, you probably noticed that tiny bubbles formed on the outside of the egg.  Those bubbles are actually the result of a chemical reaction between the vinegar and the shell.  Vinegar is an acid.  Scientists call it acetic acid (CH3COOH).  The vinegar you buy in the grocery store is about 95% water and 5% acetic acid.  Egg shells are made up of calcium carbonate (used to make chalk at one time).  When the vinegar comes in contact with the egg shell, it begins to break down the calcium carbonate into calcium and carbonate.  The calcium floats around in the vinegar.  The carbonate part reacts to form carbon dioxide gas. That's what's inside the tiny bubbles you see forming on the side of the egg.   If you allow the egg to sit in the open air, the membrane will react with the carbon dioxide floating in the air and begin to harden again.

You might also notice that your egg seems to swell as it sits in the vinegar.  This is because some of the liquid vinegar is actually moving into the egg through the shell membrane.  Because things can move through the membrane of the egg, scientists would describe the membrane as permeable.  They also describe the movement of a liquid from one solution through a permeable membrane and into another less concentrated solution as osmosis.  Osmosis is very important to both plants and animals.  For example, in our bodies, osmosis helps our kidneys recover water from our waste. If you break the membrane of your naked egg, you will notice that the yolk is floating in vinegar solution.  In a way, you have pickled the egg! 

Science Fun with Dry Ice

In this simple investigation, you'll learn some of the science behind a very cool substance known simply as dry ice. In the process, you'll learn a little chemistry and some great science lingo.  Can you say...sublimation?

Here's What You Need:

• Large plastic bowl, plastic cup, or graduated cylinder
• Warm water
• Dry Ice (you can usually find it at the grocery store or some ice cream shops ~$1/lb)
• Liquid soap
• Heavy duty gloves or tongs (for handling the dry ice)
• Hammer or mallet (for breaking the dry ice)
• Ice chest or cooler (for storing dry ice)

Safety & Dry Ice: Dry ice must be handled carefully and with adult supervision.  Because it is extremely cold (-109.3°F or -78.5°C), it can easily cause server damage to your skin if it is handled in incorrectly.  Avoid touching dry ice with unprotected skin. Never swallow dry ice or place it in your mouth.

Here's What You Do

Fill the bowl, cup, or graduated cylinder with warm water (a bit more than half way).  Use the mallet or hammer to break the dry ice into pieces that will fit easily into the container.  Using the tongs or gloves, carefully place a few pieces of dry ice into the warm water. Immediately, the water should start to churn and bubble!  You may also notice a smoky cloud forming on the top of the container and eventually spilling over the side. This cloud is safe to touch and feel.  Just remember to avoid touching the dry ice directly. After a while, the bubbling and smoking will slow down a bit.  Simply, poor out a bit of the water (cooled by the dry ice) and replace it with some warm water. 

Now, let's ramp things up a bit.  While the water is churning and bubbling, add a few drops of liquid soap and watch what happens! After a few seconds, you should see some fog filled bubbles rising out of the water.  Once again, these are perfectly safe to play with.  Grab a handful of the bubbles and squeeze them in your hand.  Notice anything? They are full of the smoky clouds that you observed when you dropped the dry ice in the warm water. 

The Science Behind Dry Ice

Dry is actually the solid form of carbon dioxide. Usually, when we talk about carbon dioxide, we talk about it as a gas; the one that we exhale during respiration and plant use for photosynthesis.  About 0.035% of the air around us is made up of carbon dioxide (most of our air is made up of nitrogen - 79%). Dry ice acts very differently than water based ice.  For example, under normal atmospheric conditions dry ice does not melt (that's why we call it dry ice).  Instead solid dry ice turns directly into carbon dioxide gas through a process called sublimation.

Try this. Grab two plates. Place a piece of dry ice on one plate and a piece of water based ice on the other plate.  Now, wait.  After an hour, you'll notice that the dry ice seems to have disappeared and there is a puddle of water where the water based ice was.  However, the dry ice didn't disappear.  Instead, it changed into a gas (one that is invisible to the naked eye).  

We make dry ice by placing gaseous carbon dioxide under intense pressure (about 870 pounds per square inch) at a very low temperature.  This will turn carbon dioxide gas into liquid carbon dioxide. The liquid carbon dioxide is then pushed through an expansion valve and into a pressure chamber.  The change in pressure causes the temperature to drop and the liquid carbon dioxide changes quickly to a solid...dry ice!   

Wondershop Fast Fact

Dry ice is great for keeping things cool.  In fact, one pound of dry ice cools three times better than a pound of water based ice.  Often people will use a mixture of dry ice and water based ice to keep things cool while they are shipped.

Most Groundhogs Predict an Early Spring!

It’s February 2nd!  You know what that means…Groundhog Day! If you are not familiar with this particular observance, this is how the whole thing works. Early in the morning on Februay 2nd, people gather around the burrow of a Marmota monax; a large rodent also known as the whistle pig, eastern marmot, southern marmot, monk, woodchuck, or groundhog. It is believed that if the groundhog sees its shadow when it climbs out of the burrow, there will be six more weeks of cold, wintery weather. On the other hand, if it doesn’t see its shadow, the warmth of spring will arrive soon. Here’s an additional little nugget to impress your friends with today: Groundhog Day is a cross-quarter day. That means it fall halfway between the Winter Solstice and Vernal Equinox.


There are a number of cities that host their own Groundhog Day celebrations…complete with their own groundhogs. Here are some of the results from this year:

• Punxsutawney Phil (Punxsutawney, Pennsylvania): Six more weeks of winter
• Jimmy the Groundhog (Sun Prairie, Wisconsin): Early Spring 
• Wiarton Willie (Wiarton, Ontario): Early Spring 
• French Creek Freddie (French Creek, West Virginia): Early Spring
  
• General Beauregard Lee (Lilburn, Georgia): Early Spring 
• Chuckles (Manchester, Connecticut): Early Spring 
• Dunkirk Dave (Dunkirk, New York): Early Spring 
• Gus (Athens, GA): Early Spring
• Buckeye Chuck (Marion, Ohio): Early Spring 
• Octoraro Orphie (Lancaster, Pennsylvania): Early Spring
• Grady the Groundhog (Chimney Rock, North Carolina): Six more weeks of winter
  
• Staten Island Chuck (Staten Island, New York): Early Spring 
• Dover Doug (Dover, Pennsylvania): Early Spring

Is there any science behind this whole Groundhog Day thing?
I did a bit of research and this is what I found out. Historically, people have observed animal behavior for clues to changes in the weather. For example, geese flying south is a sign of the coming of fall for many people living in the United States. The reappearance of hibernating or inactive animals is a sign of winter’s end. When German settlers came to Pennsylvania in the 1700s, they selected the groundhog as their seasonal forecaster.

There may also be a meteorological explanation for groundhog day. It is thought that the observance may have roots in a weather phenomenon described in the Scottish poem below:

If Candlemas Day is bright and clear,
There’ll be two winters in the year.

The idea behind this poem can be found in cultures around the world. In the poem, Candlemas Day refers to February 2nd…Groundhog Day. Farmers in ancient Europe noticed that bright, clear winter days are often very cold. We now know that this is caused by high pressure systems. Areas of high pressure pull cold air down from the north. They also sweep away any clouds that might have provided insulation. Consequently, a bright winter day (one on which a groundhog may see a shadow) may be an indication of more cold days to come.

Of course, none of this is sound evidence that groundhog can actually predict the coming of spring. Instead, Groundhog Day can be seen as a celebration of the role of scientific observation and prediction in our world. Every day, we make observations about the world around us, attempt to make meaning of those observations, and create predictions about the way things will happen in the future. Groundhog Day is wonderful example of this. Over the course of time, we have combined our observations of animal behavior and weather to create a system for predicting spring. Does it work? Well, that is a question I will leave to you and your children to explore.

Other great sites to check out on Groundhog Day:

• Groundhog Central
• Kaboose on Groundhogs Day