Experiment 7: Making Rain

This experiment is fun, especially for elementary and preschoolers. We did it as a part of our study of the water cycle.

CAUTION: you must have adult supervision for this experiment as you are dealing with a stove top and boiling water. This experiment also demonstrates how temperature is one of the main factors in changing the state of matter.

Supplies:

•  one hard covered book
• stove top heating element
• one small sauce pan
• freezer
• water

Process:

1) place your hardcover book in the freezer and allow it to sit there at least over night.
2) boil a pot of water (demonstrating evaporation)
3) once you have a cloud of steam rising from the pot, hold the book at an angle in the steam, making rain! - Watch out for your fingers! Steam is very hot!!

  Explanation:

  First in changing the states of matter: This is the approach to take with older kids who may already be familiar with the water cycle. In order to change a substance to different states of matter (liquid, solid, gas) you must apply a change in temp. A solid is a substance that has the molecules tightly packed together with stong bonds, at room temperature. A liquid is one where the molecules are spread out, some have bonds to other molecules, some are free floating. A gas is where the atoms/molecules float independantly from the other atoms, no bonds between them, rarely do they interact with the other atoms.

Water is one of the easiest to see the change in matter. If you apply heat, the liquid will evaporate, this results in steam - aka water vapor (a gas). If you apply a dramatic drop in temperature (like in a freezer) the h2o molecules will bond tightly together creating a solid (ice). Now, most children are taught these 3 states of matter at fairly young ages. But did you know there are actually 5 states of matter? The unsung heroes of matter are Plasma and the Bose-Einstein Condensiate (BEC). Plasma as a state of matter was only introduced in 1879, and the BEC was only recognized in 1995!! In a BEC the atoms are even more richly packed than in a solid. Most solids are brittle because of the way the molecules are bound (ever shattered a piece of ice?), but BEC are extremely strong, and not easy to break. A plasma is a cross between a solid and a liquid. It has properties of both.

Scientists are still hard at work on understanding matter. In fact, most scientists now refer to 'states of matter' as a Phase. For example, with water. If you start at a very low temperature you have a BEC, slowly increase the temp and youll have a solid (ice). If you slowly increase the temperature, you'll get a plasma (slushy like material, some ice, some water). Keep the temp increasing and you'll eventually get a liquid, keep the gem going and eventually you get a gas. So it is like your water has gone through different phases based on temperature. In a nutshell, matter is understood based on 2 things: temperature and the density of the molecules.

Water cycle: Did you know the amount of water found on Earth hasn't changed for billions of years? The only things that have changed are the location and whether or not the water is drinkable! The water cycle is responsible for both. It is never ending, which is why it is considered a cycle. At any given moment there are millions of gallons of water all around the globe: from oceans and seas (which contain a lot of salt); to lakes, rivers and ponds which are fresh water (low salt, but higher in other natural chemicals; to clouds, snow, ice and rain! Water is everywhere. To keep water moving about we rely on the water cycle. You see, the sun heats the surfaces of most water (puddles, rivers, oceans etc.) the only water unaffected by this first stage is water found below the ground or ice. As the sun heats the water some molecules seperate and turn to water vapor, a gas. Since water vapor is lighter than air it raises high into the sky. Way up high in our atmosphere it is very cold, the water vapor then wants to bind back to a solid, but our atmosphere is vast, so the molecules have trouble finding eachother in order to bond. Istead the bond with dust particles. This is the reason for the awesome shapes of a snowflake. Many water molecules will bind with individual dust particles, growing into ever larger snowflakes (ice). The particles might even find eachother, creating clouds. But the sun strikes these atoms as well, melting the ice back to water, which is heavier than air so it falls back to the ground as rain. (in winter the snow/ice particles grow until they are too heavy to remain aloft and they fall as snow or ice!). Once the rain is on the ground it flows down stream, back to the oceans, rivers lakes, etc. Happy learning!!

Experiment 6 - ivory soap

Talk about cool chemistry, in this experiment you can see the affect of microwaves, it is super exciting!

Supplies:
A bar of Ivory soap
Microwave Paper or ceramic plate

Process:
1) unwrap the soap and place it in the center of the plate
2) set the plate in the microwave and set the time to 2 minutes
3) Press start and let the time tun out
4) Once the microwave stops, CAREFULLY remove the plate from the oven and allow to cool for about 2 minutes until it is cool enough to handle the soap.
5) hold the soap in your hand, how does it feel?

  Explanation:
The microwave heats the soap causing it to soften. The microwaves then excite the water and air molecules in the soap. This causes the soap to lose its shape and expand as the molecules try to move in opposite directions from eachother. Evaporation of the water causes more air pockets. Since the soap has softened, and the molecules have moved away from eachother and caused air pockets, the result is a foam like substance. Remember there are 3 forms of matter: solid, liquid and gas. In a gas the molecules are very far apart, very rarely do they interact with each other, there are no bonds holding them together. In a liquid, some of the molecules are bound, some are not. In a solid, all the molecules are tightly bound together. In this experiment we are changing the state of matter from a tightly bonded solid to a more pliable liquids material.

Experiment 5: Plastic Milk

Ok, I love chemistry! I think is is so fun, and educational, when you can see with your own two eyes some substance radically change. In this experiment you can change a glass of milk into a plastic! (no joke!)

Supplies:

• 1 glass of full cream milk (I also suggest doing this with a variety of creams and milks if you can afford it - whipping cream, whole milk, etc, to see how it affects the results)
•  vinegar
• eye dropper
• wooden/plastic spoon
• microwave (or a bowl of freshly boiled water)

Process:

1. fill a glass about 3/4 of the way with the whole cream milk
2. microwave the glass for about 1 minute until milk is warm
3. Fill the eye dropper with vinegar
4. stir milk with spoon as you slowly add the vinegar
5. Hold your hand over a sink (MAKE SURE THE MILK ISN'T TOO HOT!) pour the 'milk' over your hand, catching the plastic!

Explanation:
The cream in the milk contains a chemical called casein. When you add the vinegar, the casein separates from the rest of the milk. The molecules on casein are loosely bonded together in a chain, making form on plastic! Casein is a bonding protein found in many foods that contain Phosphoric Acid. It really is also included in may products like plastic, paint, etc. Therefore, it can be found in two forms: edible and technical. Casein is similar to salt in that it doesn't change form when added to a substance. I this experiment we can see that, as we are just separating those molecules from the rest of the molecules in the milk. Casein is a protein and acts as a binding agent. So it is an important part of making cheese and yogurt. On a side note: there have been studies that show a link in adverse effects of casein in those with autism. Many with autism have food sensitivities, similar to allergies. So families will avoid dairy, thinking they are avoiding the allergy, not realizing it is the casein (found in various other foods) that might be the culprit.

Experiment 3: Acids & Bases

For today's experiment we will be doing some kitchen chemistry. It's super easy and fun for kids of all ages! Experiment - Determining pH

What You Need-

• Some Red Cabbage
• Lemon Juice,
• Baking Soda,
• Cola,
• Water,
• Vinegar
• Oil,
• milk of magnesia (if you have it on hand)
• PH chart (like the one found http://www.elmhurst.edu/~chm/vchembook/184ph.html )
• Medium sized bowl
• Grater
• Strainer
• Clear cups
• Some plastic containers

Process:

1. grate some cabbage into the medium sized bowl
2. Cover cabbage with cold water and allow it to sit for 45 minutes.
3. Strain the water mixture into a plastic container
4. Pour an equal amount of juice into the cups
5. Add 1 tsp to all but one of the cups. Mix. This should turn the mixture blue, as baking soda is a base.
6. Add lemon juice to one of the blue cups, a little at a time. How much do you need to add before bringing the color back to normal?
7. repeat #6 for each of your other liquids. One in each cup. If the liquid remains blue, then your substance is a base. But you should notice different liquids require different amounts to change the color back to normal.

  Reasoning:
We use red cabbage because the chemical makeup of the juice allows it to dramatically change color when mixed with other substances. This makes it easy to see the alkaline (pH) differences. Now, a little about pH - when you mix an acid and base, they cancel eachother out, neutralizing them. There are many neutral substances though, water and milk, for example. So, what is pH? Really all acidity is is a measurement of Hydrogen ions in a substance. They more hydrogen molecules in a substance the higher the acidity. Any substance added to water that causes an increase in the concentration of hudrogen molecules is considered an Acid. And substance added to water that decreases the concentration is considered a Base. The lase category of substances, as those that help resist changes in pH, these substances are called Buffers. As they help protect the water from changing pH level. Bonus: Now that you know which substances are acids. Think of which one would best remove the grime on an old penny. The substance with the highest acidity level. This is the one that you needed to add less of to turn the cabbage water back to its original color. Drop a penny in an old cup, add a bit of your acid ad watch it work!

Experiment 1: Drinking Water from Salt Water

I don't know about where you are, but it's been hotter than Billy Blue Blazes here. (though, now I'm curious about who Billy Blue is and who set him on fire....lol). One of the ways we try to bear the heat is through doing experiments. They can be fun, cheap, easy and educational! Drinking water is becoming more and more scarce the world over as fresh water supplies are evaporated due to global warming and droughts. You can use the following resources to do some research on the current water shortage situation: http://drinkingwaterz.com/2369-shortage-of-drinking-water.html http://whyfiles.org/131fresh_water/2.html

One of the things that has intrigued scientists from the time we emerged from the caves, was how to take the plentiful salt water of the seas and oceans and make them palatable for drinking. Ok, onto the experiment, this is a small scale version of one of the methods scientists are evaluating.

  Supplies:

• 1-2 TBS table salt
• bowl
• 3 cups water (tap water is fine)
•  small bowl or coffee cup
• stone
• thick plastic wrap

Procedure:

1. pour watere into the larger bowl
2. mix salt into the water until it is dissolved
3.  place the small bowl or cup into the water CAREFULLY, you do not want to let any of the water to flow ov the sides of the cup.
4. Place the stone in the center of the plastic wrap, so at the wrap angles down into the cup a bit.
5. carefully place the bowl in the sun
6. wait several hours. You should see water droplets on the inside of the plastic wrap dripping into the cup.
7. after a few hours allow student to taste the water in the cup - it won't be salty!

What happened:
The water from The bowl evaporated, condensing on the underside of the plastic wrap (which is why heavy duty plastic wrap is so important, lesser quality plastic wrap will allow the water vapor to escape and leave the cup empty.) salt doesn't evaporate, so essentially the evaporation process separates the water molecules from the salt ones.