How come there's no blood on my hand?

Nathan makes sure he has his
safety glasses - wouldn't want to get blood in our eyes!

Griffin was the brave one to go first in her class!

Amy can't bear to watch

Stephanie, Clark, Madison and
Jordan's family's present Pilgrims today!

Caleb turned ONE!

Hello, today was looked at our lovely germ samples. I hope the children realized that what appears to be "nothing" actually harbors lots of germs. Attached is a photo of our collection of petri dishes and a close-up of some of them.

We also did an experiment with goldenrod paper for acids and bases. I let each child take a piece home because it's very difficult to find now that almost all paper sold now is acid-free. I told them to keep it for further experimentation at home. Here are some experiments they can do with this "acidic" paper that behaves very unusually when exposed to bases.

1. Place the paper on a table.
   
2. Place a drop of water on one of the corners of the paper. Does anything happen?
3. Fill a jar with a small amount of ammonia water. Dip a cotton ball in the ammonia water and wipe it across the top portion of the Goldenrod Paper. Save the bottom half of the paper for step 5. Does anything happen?
4. As you continue to wipe designs on the Goldenrod Paper, notice that the paper does not stay red forever. What is causing the paper to change back to yellow?
5. Use a wax candle to write a secret message (such as “Hi!” or “WOW”) across the bottom half of the paper.
6. Wipe the cotton ball with ammonia water across the secret message to see what develops.

During class we did this:

1. Place the paper on a clean, dry surface.
2. Away from the paper, spray your hand with the ammonia-water solution (if you don't have ammonia, try to find a cleaner with ammonia in it like Windex)
   
3. Gently slap your hand down on the paper... oh no! It's a bleeding handprint!
4. Your audience won't believe their eyes when you hold up the paper, dripping with your "bloody" handprint.
5. Wash your hands right away.
   

How does it work?

The ammonia on the cotton ball is a base and causes the dye in the special Goldenrod Paper to change color. You probably noticed that the red color fades over time and the paper eventually changes back to its original yellow color. Why? The carbon dioxide gas that is in the air we breathe is slightly on the acidic side of the pH scale. The carbon dioxide reacts with the ammonia on the paper to produce ammonium carbonate, which changes the pH of the paper to neutral (roughly a pH of 7) and the dye changes back to yellow. If you use a stronger base like washing soda, the red message will not disappear with just the carbon dioxide in the air. You will need to use a stronger acid like lemon juice or vinegar to change it from red to yellow. You can also use Goldenrod Paper as inexpensive pH paper to classify safe household products as being either acidic or basic.

Try all sorts of different household solutions to determine whether it is acidic (will not change), neutral (will not change) or alkaline (basic, will change).

The last experiment you can do is to dissolve baking soda in water and write a message. This time, the message will not disappear by itself. Ask the children what you could do to make it yellow again and I hope they will tell you that they need to put something acidic on it like vinegar or lemon juice.

You can change the yellow goldenrod paper into red goldenrod paper by soaking the yellow paper in a weak solution of a base, such as baking soda, and allowing it to dry. Then, you can try the hand slap experiment by putting an acidic solution on your hand instead of a basic solution and see what happens!

Here's how you could try making your own color changing paper:

Make color-changing paper similar to goldenrod paper using household tumeric powder. Although tumeric is insoluble in water, we discovered it was soluble in either ammonia or ethyl alcohol. White paper dipped in a solution of ammonia with dissolved tumeric will be dyed red which turns to yellow as the paper dries; dipped in a solution of tumeric and alcohol, the paper will remain yellow as it dries. When dry, test and observe how similar and how different the paper is from the color-changing goldenrod. Note: although this paper seems to react similar to color-changing goldenrod, the color fades much faster.

Here is some basic info on acids/bases:

For thousands of years, people have known that vinegar, lemon juice and other similar foods had a sour taste. However, it has only been in the last few hundred years that mankind has understood what makes these things taste sour. These foods taste sour, because they are acids.

The term acid, comes from the Latin word acere, which actually means sour.

In the seventeenth century, an Irish chemist named Robert Boyle first labeled substances as either acids or bases. Boyle said that:

acids taste sour, are corrosive to metals, and change litmus paper red. Strong acids can badly burn you.

bases feel slippery, and change litmus blue. Solutions containing bases are also called alkaline. Strong bases can also badly burn you.

While Boyle was able to classify acids and bases into two separate groups, he was never able to explain why these substances behave the way they do.

It was not until 200 years later that scientists began to understand why acids and bases behave the way they do. In the late 1800s, a Swedish scientist named Svante Arrhenius proposed that acids dissolve in water releasing hydrogen ions while bases dissolve in water releasing hydroxide ions. This theory helped scientists understand why many different acids were similar to one another, and why many different bases were similar to one another.

Hydrogen ions contain one hydrogen atom, while hydroxide ions contain an oxygen atom, and a hydrogen atom. When acids and bases are mixed, these ions combine forming water.

The single hydrogen atom combines with the oxygen and hydrogen atom making two hydrogen atoms, and one oxygen atom, or H2O. This process is called neutralization (both salt and water are formed). When this happens both the acids and the bases become weaker, because they have been neutralized.

In 1909, the Danish biochemist Sören Sörensen invented the pH scale for measuring acidity. The pH scale ranges from 0 to 14. Substances with a pH greater than 7 and up to 14 are bases. Substances in the middle, at pH = 7, are neutral substances, for example, pure water.

One important note! Although strong acids and strong bases can be weakened when mixed together (neutralization), the same does not apply to two of the same type!! For example, ammonia and bleach (two strong bases) mixed together can be toxic. Tell your children never to mix liquids without knowing what they are doing!

We will continue with more acid/base fun next week.

New Friends

WEEK 12: Surface Tension.
This ended our series on flotation/buoyance/density/volume. The children tried to make a needle float, which you can't do by just placing it on top of the water. However, if you place it on a small piece of paper towel, the paper towel and needle will float, but then the towel will soak up water and sink, leaving just the needle. The needle defies all we've been learning about densities, buoyancy and volume, because there's another property: surface tension. Surface tension describes the attraction between the surface water molecules which causes the surface of a liquid to act like a thin skin stretched across it.

We saw that water can actually rise above the rim of a cup if we put small objects one at a time into a full cup.

Applications: don't touch the tent! Surface tension will bridge the holes in the fabric of a tent when it rains, but if you touch it, you will break the surface tension, enabling the rain to drip into the tent.

Clinical test for jaundice uses surface tension of urine. Normal urine has a surface tension of about 66 dynes/cm but if bile is present (a test for jaundice), it drops to about 55. In the Hay test, powdered sulfur is sprinkled on the urine surface. It will float on normal urine, but sink if the S.T. is lowered by the bile.

We also used food coloring on top of water to "see" surface tension being broken by an object touching the water surface.

Then we added the concept of a surfectant. Here's what we did:

1. Pour enough milk in a dinner plate to completely cover the bottom. Allow the milk to settle.

2. Add one drop of each of the four colors of food coloring - red, yellow, blue, and green - to the milk. Keep the drops close together in the center of the plate of milk.

3. Find a clean cotton swab for the next part of the experiment. Predict what will happen when you touch the tip of the cotton swab to the center of the milk. It's important not to stir the mix. Just touch it with the tip of the cotton swab. Go ahead and try it.

4. Now place a drop of liquid dish soap on the other end of the cotton swab. Place the soapy end of the cotton swab back in the middle of the milk and hold it there for 10 to 15 seconds. You'll see an amazing color show.

5. Add another drop of soap to the tip of the cotton swab and try it again. Experiment with placing the cotton swab at different places in the milk. Notice that the colors in the milk continue to move even when the cotton swab is removed. What makes the food coloring in the milk move?

How does it work?

Since milk is mostly water, it has surface tension like water. The drops of food coloring floating on the surface tend to stay put. Liquid soap wrecks the surface tension by breaking the cohesive bonds between water molecules and allowing the colors to zing throughout the milk. We call things that mess up the surface tension of water SURFECTANTS.

There's another reason the colors explode the way they do. Milk is mostly water but it also contains vitamins, minerals, proteins, and tiny droplets of fat suspended in solution. Fats and proteins are sensitive to changes in the surrounding solution (the milk).

When you add soap, the weak chemical bonds that hold the proteins in solution are alteredn The molecules of protein and fat bend, roll, twist, and contort in all directions. The food coloring molecules are bumped and shoved everywhere, providing an easy way to observe all the invisible activity.

At the same time, soap molecules combine to form a micelle, or cluster of soap molecules. These micelles distribute the fat in the milk. This rapidly mixing fat and soap causes swirling and churning where a micelle meets a fat droplet. When the micelles and fat droplets have dispersed throughout the milk the motion stops.

If you want to so more at home:

Hypothesize what would happen if you repeated the experiment using water in place of milk. Will you get the same eruption of color? Why or why not? What kind of milk produces the best swirling of color: skim, 1%, 2%, or whole milk? Why?

Application: why detergent pollution is bad – soap breaks bond between oil and water – that’s why we use soap to clean dishes, but birds depend on this. If water fowl come into contact with soap, they lose their waterproofing, water soaks them, they get heavier and sink.

Why we should wash our hands with soap: our hands have oils that can't be broken down by just water - we need a surfectant - soap - to break down the oils that may be trapping dirt and germs, which leads us to...

Miss Jen taught about light in art today.

Joseph chats with Nathan and Abby.

Lisandrea's photography captures the beauty of our study of light.

Miss Robin taught us about bacteria today.
She explained how we preserve foods with salt, dehydration and sometimes alcohol.

We talked about bacteria and viruses today. I told the children that I'd send you a link to show them how small they are: http://learn.genetics.utah.edu/content/begin/cells/scale/ Just move the scrubber to zoom in and make sure you zoom back out too. Very cool.

We talked about needing beneficial bacteria in us to break down food, and eating things like yogurt to add more beneficial bacteria. We discussed the food chain with bacteria being part of the decomposers and that without bacteria we would all die in one big trash heap. However, we like things decomposing after we're done with it, not before, so we discussed the science of food preservation. Here is a good article on the different methods of food preservation:

http://recipes.howstuffworks.com/menus/food-preservation.htm
You can read this article with your children while looking in your food pantry for all the different methods of preservation. Make it a challenge to find all of it...although it might be hard to find freeze dried.

For a demonstration of chemical preservatives, we also looked at the bread we used in the densities experiment for Week 7 which was October 20. I bought the cheapest white bread at Target since we weren't eating it and it still hasn't molded! It has been sitting in my kitchen for over two months. Scary. Stay tuned for the end of the year when we check back in to see if it ever will mold.

Your children also received a petri dish with bacteria that they collected from themselves or the church. Please take out the paper in the baggie and read it carefully and record your colony counts daily. Please be careful not to open the petri dish. PLEASE BRING IT BACK NEXT WEEK!! We want to compare all the fun, gross things we collected. Hmmm, is Boaz's nose more germy than a toilet seat?

Miss Robin brought a MRE in for us to try.
Brian, Bo, Elizabeth and Elinor all prayed for Major Shaw and his troops.

Miss Tiffany shows her class how a loom
works and discusses how much more efficient a power loom is.

Explorers!

Christopher had his lines down perfectly!
Great job Christopher!

This pictures pretty much sums up my life.
I may not look all that great but I'm surrounded by sweet children and I pray.

Miss Jen discussed lighting techniques in art today.
Douglas and Justinian the Great show off their masterpieces.

Logan's mom shot the pictures this week.
Lisandrea's photographic artistry is as beautiful as Logan's oil pastel.

Brian's apple had beautiful shading.

PINK!

Logan is back. We are so glad!