Author: Maddie Van Beek

If you live in the Midwest, you know we’ve had a lot of rain the last couple weeks! Have you ever wondered what causes rain? That’s what we’re going to focus on today! You’ll create a demonstration of a rain cloud and learn how to make your own cloud in a jar!
 
Key terms:
Evaporation: Water is heated to the point that it begins to rise and turn into water vapor; when water changes from a liquid to a gas.
 
Condensation: Water vapor in the air is cooled, and changes from a gas back to a liquid. Examples: When you see dew on the ground in the morning, or beads of water on the outside of your water bottle.
 
Precipitation: When water condenses inside a cloud forming droplets so large that the cloud can’t hold them anymore. Examples: Rain, sleet, snow, hail.
 
First of all, what is a cloud? You may think that a cloud’s only purpose is to give us rain (or funny shapes in the sky to stare at), but they actually help regulate temperature. They reflect some of the heat from the sun back into space, so a hot day is less hot if it’s cloudy. They can also serve as a “blanket” in the evening by keeping the earth’s heat near the surface. A cool night is a little warmer if there are clouds!
 
Clouds are just one part of the water cycle. Think of all the places you see water in your life… make a good list.
 
Alright, a lot of that water you may have listed (lakes, seas, oceans, ponds) is eventually heated by the sun. When the surface of that water gets warm enough, it begins to evaporate. Once that water evaporates into the sky, it begins to cool down and condenses into clouds. If enough water vapor condenses, the droplets forming the clouds get heavier and heavier. When the drops become heavy enough, they fall as rain (or if it’s cold, they fall as snow, hail, sleet, etc.)! That rain is collected in lakes, rivers, and other bodies of water that eventually flow back to the ocean, or soaks into the ground. Then, the cycle repeats! 

​For a more in-depth description of the water cycle, read here:  

​This video does a fantastic job of explaining the water cycle, cloud formation, and the different types of clouds. Don’t worry if you don’t remember all the cloud names! Watch this video about cloud formation before moving on to our activities: 

​If you want to know more about cloud formation and the specific types of clouds, check this out: 

​Now that you’ve got your cloud knowledge on point, let’s create our own raincloud!
 
Create your own raincloud:
 
YOU WILL NEED

• A mason jar
• Shaving cream
• Blue food coloring
• A dropper
• A cup of water

 
Here’s what to do!
 
This is a simple demonstration of a raincloud.

1. Pour water into your mason jar until it is about ¾ full.
2. Squirt some shaving cream on top of your jar. This is your cloud.
3. Mix a cup of water with some blue food coloring. Add as much food coloring as you need to make your water a nice blue. This is your rain!
4. Use the dropper to drop the blue food coloring on top of the shaving cream. Observe what happens. Soon enough, your “rain” makes it through the shaving cream and precipitates into the jar. Even though this is very simple, it is a good demonstration of how a cloud works. Clouds get heavier and heavier with water until they can’t hold it anymore. Then it rains!
5. Try it again, but pay attention to how many drops it takes before it starts to “rain.”
6. Experiment with making different cloud shapes. Can you mimic the shapes of a stratus? Cumulus? Nimbus? Look back at the video for reference and see how many cloud models you can make!

 
Now we’re going to try something a little more complicated. You’re going to make a real cloud in a jar!
 
YOU WILL NEED:

• 2 liter plastic bottle
• Duct tape
• Bicycle pump
• Rubbing alcohol

 
Here’s what to do!

1. Clean out a 2 liter soda bottle.
2. Open the bottle and add a few teaspoons of rubbing alcohol.
3. Close the bottle and rotate it around to coat the inside of the bottle with the rubbing alcohol. Rubbing alcohol evaporates very quickly, so the rotation is helping it evaporate faster.
4. Put your safety glasses on! The idea is to force air into the container with the bicycle pump. Remove the cap from the bottle and cover it with duct tape to reseal the bottle. How you seal the bottle may vary depending on your type of bicycle pump.
5. Poke a small hole in the middle of your duct tape seal and place the mouth of the bicycle pump over the seal. Make sure no air can escape.  If you have a needle bicycle pump, a cork may work better than duct tape.
6. You may need help to hold the pump over the mouth of the bottle while you pump air into it.
7.  Be careful! You don’t want to pump in so much air that the bottle bursts. Try about 5-7 pumps, and then quickly remove the pump from the bottle.
8. Voila! You suddenly have a cloud inside a bottle!
9.  Try pumping air back into the bottle again… the cloud disappears!

 
Explanation: In the bottle, there’s air, water vapor (always in the air) and rubbing alcohol (molecules that act as places where the water molecules can land and begin to condense. Normally dust particles in the air perform this function instead of rubbing alcohol).  When you pump the air in, you’re increasing pressure and ALSO increasing temperature.  When you release the pressure, there’s a sudden cooling effect. What do we know about cooling? It causes condensation! Remember, condensation is what forms clouds. That’s also why when we re-add the pressure, the cloud disappears. You’re increasing pressure and heat once again, which causes that cloud to evaporate.
 
Another way to create a cloud:
This experiment uses boiling water and matches, so be careful and ask an adult for help.
 
Video reference: 

​YOU WILL NEED:

• Mason jar
• Boiling water
• Matches
• Ice cubes

 
Here’s what to do!

1. Fill the Mason jar about half full with boiling water.
2. Place the lid back on the jar.
3. Put a few ice cubes on the lid and observe. You’ll see that the water vapor begins to condense on the inside of the jar. Not a cloud! Remember our last experiment… the water vapor needs something to cling to in order to form a cloud.
4. Remove the lid again. Light a match, wait about five seconds, and then blow it out. Lower the match into the jar to let some smoke travel in (you don’t need a lot).
5. Replace the lid and put the ice cubes back on top.
6. A cloud forms! The addition of the smoke allowed the water vapor to condense, cling to the particles of smoke in the air, and form a cloud.

 
BONUS: If you want to learn how to predict weather based on cloud formation, check out this video! See if you can out-predict the weather person! 

Image and video credits:
 
Tedfloyd. 1996. Natural Water Cycle.  Uploaded from Wikimedia Commons on 6/19/2016. 
https://commons.wikimedia.org/wiki/File:Natural_water_cycle_1.jpg 
File used in accordance with the Creative Commons CC0 1.0 Universal Public Domain Dedication license. 
 
Beautiful Science. 2015. The science of clouds. https://www.youtube.com/watch?v=dnL5LPil77M
 
Nyren, E. 2016. How to make a cloud in a jar.
https://www.youtube.com/watch?time_continue=130&v=ODCjZQUxCGw
 
ZoneA. 2017. How to predict the weather by looking at the clouds. https://www.youtube.com/watch?v=I00vcHLJXCc
 
References:
 
Good handout about cloud types:
Funk, T. Cloud classifications and characteristics.
The Science Corner. https://www.weather.gov/media/lmk/soo/cloudchart.pdf
 
Jessika Toothman "How Clouds Work" 5 May 2008.
HowStuffWorks.com. <https://science.howstuffworks.com/nature/climate-weather/atmospheric/cloud.htm> 26 June 2018
 
Robert Lamb "How Weather Works" 19 August 2008.
HowStuffWorks.com.
<https://science.howstuffworks.com/nature/climate-weather/atmospheric/weather.htm> 25 June 2018
 
mathtutordvd. 2012. Cloud in a bottle.
​ScienceandMath.com. https://www.youtube.com/watch?v=wagrbfKV5bE

Author: Maddie Van Beek

Summer is in full swing, so we hope you’ve been able to get outside! Today, we are going to have fun with three different sandy experiments.
 
First of all, what is sand? Where do you see sand?
 
You might think of a sandbox, the beach, or the desert. Sand is really just small pieces of rock that have been broken down over time. The sand you see at the beach may contain little shell pieces as well. Over time, the repeated wear from wind, water, and other elements break rocks and pebbles into smaller and smaller pieces. 

Erupting Sand Volcanoes
Last week, we talked about acid-base reactions when we created fizzing chalk paint.

Review here: Science of chalk

We’re going to use this same principle to create sand volcano eruptions.
 
YOU WILL NEED:

• A sandy area (beach, sandbox, or store-bought sand)
• Empty plastic bottle
• Water
• Baking soda
• Vinegar

 
Here’s what to do!

1. Fill your plastic bottle about 1/3 full with water. Add about ½ cup of baking soda (your base) and shake it up until it’s well blended.
2. Build a volcano shape around your water bottle. Make sure you don’t get sand inside the bottle.  You may need to wet the sand in order to shape it into your ideal volcano. The opening of your volcano will be the mouth of the bottle.
3. Dump some vinegar into the mouth of your volcano and watch it erupt!
4. Experiment: Try using different amounts of baking soda or vinegar.  Does more or less make a difference? 

​
Quicksand
One type of sand you hopefully have not had to deal with is quicksand. This is formed when sand or silt becomes mixed with lots of water. When a person or animal steps into quicksand, it can be very difficult to get out. 

​The quicksand we’re creating doesn’t actually contain any sand, but it mimics the way quicksand acts. Sometimes it seems like a solid, but it also can act like a liquid. This is called a non-Newtonian fluid. You might’ve created this before if you’ve ever tried making Oobleck!
 
Create your own “quicksand”
 
YOU WILL NEED:

• A pan or container
• Cornstarch
• Water

 
Here’s what to do!

1. You can create as much quicksand as you want! Dump equal amounts cornstarch and water into the pan, and then mix it together.
2. If the quicksand seems too dry, add a little water. If it’s way too runny, add a little cornstarch.
3. Put your hand in the “quicksand” and try to pull it out quickly. What happens? You’re stuck! Try it again, but slower. What do you notice? When you move slowly, it’s easier to remove yourself from the quicksand. This mimics what quicksand is like. The best way to get out of quicksand is to avoid panic and move slowly.

 
Sandy Slime
Who doesn’t love a little slime? Use this classic slime recipe and mix in sand for a beach-themed mess!
 
Before we get messy, let’s review the science behind this particular type of slime. 

What is slime? 
The slime we are going to create today is a substance called a polymer. A polymer is a large molecule formed from lots of smaller molecules. These smaller molecules, called monomers, form a long chain. 

Poly = many
Mono = one
Mer = parts

A polymer has many parts, a monomer has one part. Lots of monomers together form a polymer!
​
Think of the monomers as beads, and the polymer as a necklace made by stringing the beads together. 

Where do we see polymers in our daily lives? 
Polymers appear in many products that you see all the time, such as plastic or rubber. Another common polymer is the DNA in your body! DNA is a chain present in all the cells of your body, and it’s what makes you uniquely different from everyone else! 

In our slime recipe, one of the main ingredients is glue, which is actually a liquid polymer. The molecules of glue are in separate little strands before you add anything to it. Once you add the special ingredient (laundry starch) to the glue, it acts as a binding agent that links all the little strands together to create a more solid polymer, or in other words... SLIME. 

What’s happening when you add liquid starch to glue? Glue is already a polymer, but it isn’t a very strong one. Cross-linking occurs when you add a binding agent to a weak polymer to make it stronger (see the image below). The once weak individual polymer strands are made sturdier because they are cross-linked by the binding agent! ​

Now that you understand more about polymers, let’s make some slime! 
 
YOU WILL NEED:
(You can purchase our basic slime kit here: Polymer Science Kit)

• White liquid school glue
• Liquid laundry starch
• Water
• Sand
• Bowls
• Measuring cups

Here’s what to do! 
​
1. Measure ½ cup of the clear craft glue and dump it into the mixing bowl.

2. Pour ½ cup of water into the mixing bowl and use the spoon to stir the water into the glue until it looks smooth and well-blended. Write down your observations so far. How does adding water to the glue change it?

3. Mix in your sand! Add a few tablespoons or so and stir it up.

4. Add ½  cup of liquid starch to the mixing bowl and stir it in. How does the consistency of the glue change once you add the starch? Record your observations.

5. Once you stir the starch in, pick up your slime and play with it! What does it feel like? Look like? Is this what you expected to happen? 
 
Happy experimenting! 

Image Credits
Sepp, S. 2011. Close-up of sand from the Gobi Desert, Mongolia. Used in accordance with the Creative Commons Attribution Share-Alike 3.0 Unported License. Uploaded from wikimedia commons on 6/11/2018. No changes were made.  

Dunn, A. 2005. Quicksand and a warning about it at a gravel quarry in England. Used in accordance with the Creative Commons Attribution Share-Alike 2.0 License. Uploaded from wikimedia commons on 6/11/2018. No changes were made. 

Cross-linking. Created by Dr. Erin Nyren. 
​
Slime photo taken by Maddie Van Beek. 

Resources:
https://www.education.com/activity/article/Quick_Sand/
https://littlebinsforlittlehands.com/best-sandbox-volcano-eruption/
https://littlebinsforlittlehands.com/homemade-sand-slime-recipe/
https://wiki.kidzsearch.com/wiki/Quicksand
https://www.livescience.com/34748-what-is-sand-beach-sand.html