Donna Forbis

Blobs in a Bottle

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If you have ever seen a lava lamp, you know how mesmerizing it is to watch the blobs rise and sink through the liquid. Most lava lamps contain a combination of water and wax. As a solid, wax is heavier than water and will sink to the bottom of the container. When wax melts into a liquid, it is lighter than water and will rise or float on top of the water. A lava lamp works by having a heat source at the bottom of the lamp to melt the wax. The melted wax rises through the water, but then sinks as it cools off and begins to harden again.

In this demonstration, we will re-create the effects of a lava lamp using common household items, with no electricity needed! The “blobiness” effect will wear off during the demonstration, but you can regenerate it whenever you want!

The Experiment

Supplies: A clean 1-liter clear soda bottle, tap water, vegetable oil or baby oil, fizzing tablets (such as Alka Seltzer), and food coloring.

What to do: Pour the water into the bottle until it is about 1/3 full. Use a measuring cup or funnel to slowly pour oil into the bottle until it’s almost full. You may have to wait a few minutes for the oil and water to separate. Add about 10 drops of food coloring to the bottle (red is nice, but any color will look great.) The drops will pass through the oil and then mix with the water below. Break a seltzer tablet in pieces and drop a piece into the bottle. DO NOT PUT THE CAP ON THE BOTTLE. Observe what happens. Continue to add pieces of the seltzer tablet as you see fit. What happened inside the bottle after you added the seltzer tablet pieces?

What is happening: The oil floats on top of the water because it is less dense (see the liquid density experiment for more information). The fizzing tablet contains a mixture of powdered acids and bases that begin to combine as they dissolve in the water (see the carbon dioxide experiment). As the tablet dissolves, it creates carbon dioxide gas. As the gas rises through the oil, it takes some of the water with it. When the gas bubble reaches the surface of the oil, the bubble “pops,” allowing the gas to escape, and the water sinks back down through the oil to the bottom.

Extra: Once your tablet pieces are completely dissolved and the reaction is over, you can store the oil & water mixture with the cap on to save for later. To make more blobs, simply add more tablet pieces!

Links

To see this demonstration in action, head over to BASF’s YouTube page.

Make Carbon Dioxide

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Carbon dioxide is a clear, odorless gas that occurs naturally in our environment. It is one of the most important gases on Earth because it is one of the components necessary for plant survival. Trees and plants need carbon dioxide and water to make their own food, and they give off oxygen in the process. Humans need the oxygen to breathe and many of our food sources are from plants, so with out plants, we would suffocate and starve! Just like plants take in carbon dioxide and give off oxygen, humans take in oxygen and give off carbon dioxide. This kind of mutually beneficial relationship is called symbiosis.

Chemistry is the study of different substances and how they interact. Chemical compounds fall into different categories, depending upon where they fall on the pH scale. pH stands for “potential of hydrogen,” and the pH scale measures how much hydrogen is contained within any given compound. Vinegar is an acid. Acids fall below 7 on the pH scale. They tend to have a sour taste and can cause a burning sensation in nasal passages when smelled. Acids are sticky and react with with metals. Baking soda is a base, meaning that it falls above 7 on the pH scale. Bases are generally odorless and have a bitter taste. They tend to be slippery and they react with fats and oils. Water is neutral, meaning it falls right in the middle of the pH scale at 7. When acids and bases combine, the reaction is a volatile one, but the acids and bases can balance each other out, resulting in compounds that are closer to neutral. This experiment will combine common substances to create an interaction that will produce carbon dioxide. Carbon dioxide, or CO2, is the same gas that is used to make soda fizzy, so releasing CO2 can cause bubbles!

The Experiment

Supplies: a tall glass, baking soda, vinegar, liquid dish soap, tap water, food coloring (optional).

What to do: DO THIS EXPERIMENT OUTSIDE OR IN THE SINK. Fill the glass half full of water. Add a tablespoon of baking soda and five drops of detergent. Add 2-3 drops of food coloring, if you want. Stir well to combine ingredients. Last, add a quarter cup of vinegar. What happened when the vinegar was added?

What is happening: Water has hydrogen and oxygen as its elemental building blocks. Baking soda and vinegar both have carbon, hydrogen, and oxygen, but the proportion of “ingredients” in each of these chemical compounds is different. Baking soda also has a fourth ingredient – sodium. When all the atoms from all the compounds are allowed to combine, they react violently. The bonds holding the atoms of each compound break, allowing the atoms to reorganize into new compounds. The hydrogen from the vinegar interacts with the sodium and the carbon from the baking soda and forms two new substances – sodium acetate (a salt) and carbonic acid (a liquid). Carbonic acid is highly unstable, so even as the carbonic acid is being formed, it is also breaking apart. Immediately the atomic bonds in the carbonic acid break down, resulting in liquid water and carbon dioxide gas. The gas is lighter than the water, so it moves upward through the liquid in the form of bubbles!

Links

For a more detailed discussion of this experiment, visit the Wonderopolis website.

Evaporate Some Water, Part 2

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In the first Evaporate Some Water experiment, we explored the water cycle and how water can be converted into water vapor using only the energy from the sun. But what happens to water that is not in a stream, lake, or ocean?

The Experiement

Supplies: Two clear glasses of the same size, a marker pen, a piece of cardboard that will cover one of the glasses, tape, food coloring (optional).

What to do: Put a vertical strip of tape on the side of each glass. Measure out enough water to fill each glass about 3/4. Fill each glass with the exact same quantity of water. Add food coloring, if available. On the piece of tape, mark the water level on each glass. Tape the cardboard cover onto one of the glasses so that it does not fall off. Place both glasses in direct sunlight and leave them for a full day of sunlight. Then observe the level in each glass. Which glass had more water evaporated out of it?

What is happening: The piece of cardboard blocked the water vapor from reaching the atmosphere, so the water stayed inside the glass. Blocking the top of the glass created a miniature closed ecosystem, where the water evaporated into the space in the top of the glass, then condensed and returned to the pool of water below. The Earth is a closed ecosystem on a grand scale, with our atmosphere trapping the water and keeping it here, just like the cardboard kept the water in the glass.

Links

To find out more about closed ecosystems and instructions on how to make one of your own, visit NASA’s Climate Kids website!

Evaporate Some Water

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Matter exists in one of four different categories or states – solid, liquid, gas, or plasma. Some molecules can exist in multiple states, while others will only ever be in one. When we think of water, we usually think of the liquid that comes out of our faucet, falls from the sky as rain, or fills creeks, rivers, ponds, lakes, and oceans. The water in these examples is in liquid form, but if you heat up water, it changes. It stops being a liquid and becomes a gas called water vapor. Another common name for this vapor is steam. Similarly, when liquid water gets really cold, it changes state again. This time it becomes a solid – ice.

The water that exists on the surface of the Earth is the same water that has been here for millions of years. On the surface of the planet, water can be found in liquid form (water), or as a solid (snow and ice). Water can also be found in the atmosphere as water vapor. Water moves from the atmosphere to the planet as precipitation. Water moving from the planet to the atmosphere is called evaporation. When there is more energy from the sun present, like on a hot, sunny day, water evaporates more quickly. Humidity refers to the amount of water vapor in the air. High humidity is when a large amount of water vapor is present. Low humidity is when little water vapor is present.

The Experiment

Supplies: A hot sunny day, chalk, a paper cup of water, a flat portion of concrete, a watch or clock.

What to do: Pour some water on the concrete or asphalt to make a puddle about 18 inches in diameter – preferably in full sunlight. Use the chalk to make a circle around the edge of the puddle. Every 15 minutes or so come back to examine the puddle and draw a new circle around it.
What happened to the puddle each time you checked on it? How long did it take for the puddle to disappear entirely?

What is happening: Energy from the sun, in the form of heat, changes the water from liquid to water vapor, causing it to evaporate into the atmosphere.

Links

To learn more about evaporation and the water cycle, head over to the National Geographic Kids website.

Work With Ice Power

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Everything in the universe is made of matter, but not all matter is the same. Matter can be sorted into one of four different categories – solid, liquid, gas, or plasma. Some molecules will only ever be found in one of the four states, while other molecules can shift from one state to another, depending upon the conditions surrounding that molecule.

One of the things that can make a molecule shift from one state to another is temperature. When we think of water, we usually think of the liquid that comes out of our faucet, falls from the sky as rain, or fills creeks, rivers, ponds, lakes, and oceans. The water in these examples is in liquid form, but if you heat up water, it changes. It stops being a liquid and becomes a gas called water vapor. Another common name for this vapor is steam. Similarly, when liquid water gets really cold, it changes state again. This time it becomes a solid – ice.

Different states of matter are organized differently at the atomic level, as demonstrated in the picture. The more energy that molecules are exposed to the more “excited” they become, and they start to move around more. Exposing water to increasing or decreasing amounts of energy, in the form of heat, causes the water to change its state. Molecules may need a different amount of space, depending upon what state they are in.

The Experiment

Supplies: A freezer-safe container with a lid, water

What to do: Fill the container with as much water as you can while still being able to carry it without spilling! Set the container in the freezer where it won’t be disturbed for several hours. Now, add more water, until the container is filled all the way to the brim. Set the lid loosely on the top. DO NOT TIGHTEN THE LID. After several hours, come back to check on your container. What happened to the water? What happened to the lid?

What is happening: As with the water/rubbing alcohol experiment, when water is in its liquid form, the molecules can squish together more easily. In its solid form (ice) the water molecules take up more space, so the water will expand in volume as it freezes. For a variation of this experiment, pour 1/2 cup of water into a liquid measuring cup. Make sure the water is to the line. Freeze your measuring cup and water for several hours. Where on the measuring cup is the surface of your ice?

Links

For more information on states of matter, check out the Chem4Kids website.

Find the Invisible Space

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Matter is what scientists call all the stuff around us. Matter may come in all different colors, shapes, and sizes, but all matter can be “broken down” into smaller parts – all the way to the atomic level. At its core, matter is just a bunch of different atoms that have gotten together in an organized fashion. Atoms are the core building blocks of everything around us.

Atoms are super tiny, so small that they can only be seen with a special kind of microscope. Atoms have a center, called a nucleus, which contains parts called protons and neutrons, and they have things called electrons that float around the outside of the nucleus, sort of like how the moon “floats” around the Earth. Every atom has some “invisible space” that exists between the nucleus and the electrons.

Think of a bin filled with loose LEGO. Each individual piece represents an atom. When you put two or more atoms together, you create a molecule. Different molecules have different shapes and sizes. When you put multiple molecules together, you get a compound. Compounds can be combined to make anything, just like LEGO bricks, but regardless of what you build, the invisible space still exists at the atomic level.

Even though we can’t see the invisible space, we can still prove that it exists using everyday objects.

The Experiment

Supplies: A 1 cup measuring cup, a measuring cup that is at least 2 cups, water, and rubbing alcohol.

What to do: Measure EXACTLY 1 cup of water very carefully and pour it into the large measuring cup. Measure EXACTLY 1 cup of rubbing alcohol and pour the rubbing alcohol into the large measuring cup. Check the amount of liquid in your large measuring cup. Is it 2 cups of liquid?

What is happening: Water molecules consist of a single oxygen atom combined with two hydrogen atoms. Rubbing alcohol molecules have three carbon atoms, seven hydrogen atoms, and a single oxygen atom. The shape of the rubbing alcohol molecules allows them to “slide” in-between the water molecules and fill the invisible spaces. This is one case where 1 + 1 does NOT equal 2!

Links

To learn more about atoms, check out Rader’s Chem4Kids website.

Sky Watching

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The world around us contains so much more than just the plants, animals, and geography that makes up our planet. Earth is just one piece of the universal puzzle. There are other planets, solar systems, galaxies, and more spread so far across the universe that it would take millions of years, traveling at the speed of light, just to get there. The black hole picture we have from the Messier 87 galaxy may be new to us, but in reality, this image is what the M87 black hole looked like over 55 million years ago!

Distances in the universe are so large they are measured in “light-years.” A single photon of light can travel 186,000 miles in a single second. A light-year is the number of miles that a single photon of light can travel in one year, nearly 6 trillion miles! To figure out just how far away that black hole is, you would have to multiply the 6 trillion miles (for a single year) by the 55 million years it would take to travel there. That’s a lot of zeros!

Luckily for us, there are other objects in the universe that are much closer, so close that we can see them without too much effort. Some things we can see with our own eyes. Others require a little help to be seen. Sometimes we look at just the object itself, like the moon, or other planets. Sometimes we look at a cluster of objects, like different stars, and identify them by the patterns they make. These patterns are called constellations. Constellations are often named for common objects, animals, or ancient mythological figures like Orion.

Because everything in the universe is constantly in motion, what we can see changes depending upon our location, what time of day it is, or even what time in the year it is. There are lots of resources to help you find what you are looking for. Some links are posted below. When you are ready, go outside, take a good look around, and see what there is to see!

The Experiment

Supplies: Your eyes.
Optional: A pair of binoculars or a telescope

What to do: Locate, but do not look directly, at an object in the sky that is eight light minutes from the Earth. Then locate an object in the sky that is 1.3 light seconds from the Earth.


What two things did you find?

Links

Visit the Dome Planetarium at the Peoria Riverfront Museum for programs and information about outer space.
To find out what objects will be visible in the night sky tonight visit TimeAndDate.com’s Night Sky Guide.
Sky & Telescope magazine has an interactive sky chart that can help identify constellations.
Explore Astronomy on the American Museum of Natural History’s website.

Shapely Leaves

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Trees are an important part of our ecosystem. Humans breathe in oxygen and breathe out carbon dioxide. Trees take in carbon dioxide and expel oxygen as part of the photosynthesis process. Without trees, we would have no air to breathe.

The photosynthesis process happens in the trees leaves. Beyond just being a “food factory,” leaves are important in other ways. They provide shade for animals and other plants and helps combat global warming, they help slow down air currents, making it less windy, and they provide a sheltered home for birds, insects, and other creatures that are necessary for a healthy ecosystem.

Trees are identified by many different characteristics, like the kind of bark on their trunks or the size and shape of their leaves.

The Experiment

Supplies: Tree leaves to be collected.

What to do: Collect tree leaves of the following types (Refer to the web or a tree identification book to find what kinds of trees have these leaves.)

Name Each Species of Tree:
Smooth Edges Simple Leaf ______________________________
Simple Leaf with Lobes or Teeth ______________________________
Palmately Compound Leaf ______________________________
Pinnately Compound Leaf ______________________________
Acicular Shaped Leaf ______________________________

Links

To find out more about the trees around you, use the Arbor Day Foundation’s tree identification field guide, What Tree is That?

Go “Birding”

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Birds are an important part of our ecosystem. Some eat insects and worms, which helps keep those creatures from taking over our yards. Others eat fruits and distribute the seeds of those fruits in their droppings, effectively “planting” new bushes and trees when they do.

Head outside and observe some birds that make their homes in Illinois.

The Experiment

Supplies: None, just your eyes.


What to do: Observe each of the following:

A member of the Thrush family (The most common one is gray with a reddish-orange breast, relishes earthworms, and goes by the scientific name of Turdus migratorius.)
What species of bird did you see? _________________________

A member of the Jay family (The most common one is blue and white with black markings, is known for its noisy calls that mimic other birds, and goes by the scientific name of Cyanocitta cristata.)
What species of bird did you see? _________________________

A member of the Finch family (The most common one is black and yellow with white markings, loves thistles and milkweed, and goes by the scientific name of Spinus tristis.)
What species of bird did you see? _________________________

Links

To find out more about bird species you see when you are out in your yard or out on a hike, visit All About Birds from The Cornell Lab at Cornell University.

Official Illinois Nature Species

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Each state has its own state nature symbols – plants and animals that are native to that state. Some of these symbolic plants and animals are easy to find. Finding others might require a trip to a special location, like a botanical garden or a zoo. Do you know what plants and animals are symbolic to Illinois?

The Experiment


Supplies: None. Just your eyes, and perhaps a web search.


What to do: Identify (and observe, if possible) the following:


Amphibian _________________________
Animal _________________________
Bird _________________________
Fish _________________________
Flower _________________________
Grass _________________________
Insect _________________________
Mineral _________________________
Reptile _________________________
Tree _________________________

Did you know Illinois had so many state symbols? Were you able to see all of these in person? If not, which ones are you still missing?

Links

For more information about the state symbols of Illinois, check out the State Symbols web page on the Illinois.gov website.