Author: Maddie Van Beek

​Think back to a time that you’ve stood in a pool or a lake. When you look down, do your legs look like they normally do? No! Have you ever wondered why your legs look bent, or as if they are shorter? This weird effect is called refraction! 

Refraction happens when a wave travels from one medium to a second medium in which the wave travels at a different speed (the speed of light is only constant in a vacuum). For example, when light goes from traveling through the medium of air to the medium of water, the speed of the light slows down and the wavelength shortens (the frequency of the wave—that is, the number of times the wave repeats in a given time—remains the same). The amount of refracting that occurs depends on the index of refraction. We can calculate the index of refraction (n) by dividing the speed of light in a vacuum (c) by the speed of light in that specific medium (v). That is:

Index of refraction = vacuum/specific medium

n = c / v
For example, the speed of light is 299,792,458 meters per second, but is commonly denoted as c. Let’s try calculating the refractive index for a vacuum.

Index of Refraction (n) = c (the speed of light) / c (the speed of light)

Anything divided by itself equals 1. Therefore, the refractive index for a vacuum is 1.

Below, you can see that the all other mediums have a larger refractive index than in a vacuum. This is because the speed of light in any other medium will be slower than in a vacuum. Therefore, the index of refraction will usually be over 1. Negative refractive indexes are only achieved with synthetic materials that possess uncommon refractive properties.

References:

• http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/refr.html#c3
• http://en.wikipedia.org/wiki/Refraction
• http://teachinginroom6.blogspot.com/2012/04/light-refraction-fun-independent.html
• http://science.howstuffworks.com/nature/climate-weather/storms/rainbow1.htm

Image and Video Credits in order of appearance: 

Image 1: Bcrowell, 2014. Refraction-with-soda-straw-cropped. Uploaded from Wikimedia Commons on 7/31/2016. https://en.wikipedia.org/wiki/Refraction#/media/File:Refraction-with-soda-straw-cropped.jpg File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license.

Image 2: JrPol, 2015. Refraction in a glass of water. Uploaded from Wikimedia Commons on 7/31/2016. https://upload.wikimedia.org/wikipedia/commons/thumb/f/f1/R-DSC00449-WMC.jpg/800px-R-DSC00449-WMC.jpg File used in accordance with the Creative Commons Attribution-Share Alike 4.0 International license. No changes were made. 

​Home Science, 2014. Amazing water trick - Amazing science tricks using liquid. Uploaded from Youtube on 7/31/2016. https://youtu.be/G303o8pJzls

Image 3: Inaglory, 2007. An inferior mirage on the Mojave desert in spring. Uploaded from Wikimedia Commons on 7/31/2016. https://upload.wikimedia.org/wikipedia/commons/7/7c/Desertmirage.jpg File released into the Public Domain. 

Image 4: Сергей Banifacyj Морозов, 2008. Rainbow after the rain, Grodnow, Belarus. File uploaded from Wikimedia Commons on 7/31/2016.
https://upload.wikimedia.org/wikipedia/commons/thumb/f/f4/%D0%A0%D0%B0%D0%B4%D1%83%D0%B3%D0%B0_%D0%BD%D0%B0%D0%B4_%D0%93%D1%80%D0%BE%D0%B4%D0%BD%D0%BE.jpg/1280px-%D0%A0%D0%B0%D0%B4%D1%83%D0%B3%D0%B0_%D0%BD%D0%B0%D0%B4_%D0%93%D1%80%D0%BE%D0%B4%D0%BD%D0%BE.jpg File used in accordance with the Creative Commons Attribution-Share Alike 4.0 International license. No changes were made. 

Author: Maddie Van Beek

While getting tan isn’t a bad thing, you want to protect your skin from getting burned. When your skin gets red rather than tan, it’s been burned. While getting burned once or twice isn’t the end of the world, continued sun burns could cause skin damage or increase your risk of skin cancer. 


How can you protect your skin? 
You can be proactive and avoid getting burned by wearing protective clothing that has a high UPF rating. You can also apply sunscreen to protect your skin, but make sure you do this BEFORE you go outside and reapply throughout the day. The Skin Cancer Foundation recommends that you reapply every two hours, just to be safe. 


What’s the difference between SPF and UPF? 
UPF is the rating for clothing that protects you from the sun while SPF is the rating system for sunscreen. SPF stands for Sun Protection Factor while UPF stands for Ultraviolet Protection Factor. The SPF rating measures the amount of time it takes for your skin to redden in the sunlight, while UPF measures the amount of the sun’s UV rays that can penetrate the clothing. If a shirt has a UPF of 35, then 1/35th of the UV rays are making it through the fabric. 


How does sunscreen block the sun? 
There are a few different types of sunscreen, but all sunscreen does at least one of two things. It either contains chemical compounds that absorb the UV light from the sun, or it contains ingredients such as zinc oxide or titanium dioxide that act as a block that reflects the UV light from your skin. 


Check out this link to learn more about the science of sunscreen: ​

Author: Maddie Van Beek

Fingerprints
Take a close look at your fingertips.  All those swirly marks in your skin are your fingerprints, and yours are incredibly unique. Did you know that just like snowflakes, no two fingerprints are alike? 

Fingerprints are just one tool used in a field called forensic science. Forensic science is the science of gathering information about past events, and using that information in a court of law. When investigators are trying to determine who committed a crime, they use forensic science! Crime scene investigators often use fingerprints to help catch the criminal. 

Play the Whodunit game to learn more about fingerprint types and solve a crime scene! ​

Now that you’ve played the Whodunit game, you should know that there are THREE types of fingerprints: Loop, Arch, and Whorl. ​

Take your own fingerprints! 

What kind of fingerprint do you have? 

YOU WILL NEED:

Paper

Pen

Ink pad

YOU WILL DO:

1. Draw 10 boxes on a white piece of paper.

2. Label each box for each finger (Left Pinky, Left Ring, Left Middle, etc.)

3. Press your right thumb on an open ink pad. Make sure you start with your thumb tilted to the left and then roll to the right so that the whole pad of your thumb is covered in ink.

4. Press your right thumb on the box labeled “Right Thumb” and roll your finger just like you did to apply the ink. 

5. Repeat this for each finger on your right hand, and then your left hand. 

6. Analyze your prints! Are you Loop, Arch, or Whorl? 

Fingerprints are just one way that our bodies are uniquely different from one another! ​

DNA Project Key

Body: 

Pink = Medium, short and stocky

Yellow = Tall and lean

Orange = Tall and muscular

Green = Small and thin


Ears:

Pink = Pointed

Yellow = Large and floppy

Orange = Medium square

Green = Medium and floppy

Nose: 

Pink = Pink/Red

Yellow = Black

Orange = Brown

Green = Spotted

Snout:

Pink = Long and thin

Yellow = Short and smushed

Orange = Droopy jowls

Green = Medium and square

Eyes:

Pink = Blue

Yellow = Brown

Orange = Grey

Green = Green

Coat Color:

Pink = Brown

Yellow = Black

Orange = Spotted

Green = White

Fur: 

Pink = Short and Curly

Yellow = Short and course

Orange = Long and shaggy

Green = Long and curly 

Tail: 

Pink = Long and lean

Yellow = Short and stubby

Orange = Medium

Green = Curly 

Legs:

Pink = Short and stubby

Yellow = Long and lean

Orange = Medium

Green = Muscular

References:
​

• http://learn.genetics.utah.edu/content/inheritance/activities/pdfs/A%20Recipe%20for%20Traits_Public.pdf
• http://www.pbs.org/wgbh/amex/dillinger/sfeature/sf_whodunit.html
• http://www.slideshare.net/MrsTabor/dna-for-7th-grade
• http://www.chem4kids.com/files/bio_dna.html
• http://tfscientist.hubpages.com/hub/explaining-dna-to-a-six-year-old

Image Credits:

Image 1: Fingerprint arch. Uploaded from Wikimedia Commons on 7/17/2016. https://upload.wikimedia.org/wikipedia/commons/c/c5/Fingerprint_Arch.jpg Image was created by the United States Department of Commerce and is in the Public Domain. 

Image 2: Fingerprint loop. Uploaded from Wikimedia Commons on 7/17/2016. https://upload.wikimedia.org/wikipedia/commons/0/06/Fingerprint_Loop.jpg Image was created by the United States Department of Commerce and is in the Public Domain. 

Image 3: Fingerprint whorl. Uploaded from Wikimedia Commons on 7/17/2016. https://upload.wikimedia.org/wikipedia/commons/4/49/Fingerprint_Whorl.jpg Image was created by the United States Department of Commerce and is in the Public Domain. 

Image 4: Shaffee, 2015. Autosomal recessive - mini. Uploaded from Wikimedia Commons on 7/17/2016. https://upload.wikimedia.org/wikipedia/commons/thumb/4/46/Autosomal_recessive_-_mini.svg/800px-Autosomal_recessive_-_mini.svg.png File used in accordance with the Creative Commons Attribution-Share Alike 4.0 International license.

Image 5: Lynch, 2011. Snow flakes. Uploaded from Wikimedia Commons on 7/17/2016. https://upload.wikimedia.org/wikipedia/commons/thumb/2/23/Snow_Flakes.jpg/800px-Snow_Flakes.jpg File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license.

Image 6: 1936. Joy Oil gas station blueprints. Uploaded from Wikimedia Commons on 7/17/2016. https://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Joy_Oil_gas_station_blueprints.jpg/1024px-Joy_Oil_gas_station_blueprints.jpg File is in the Public Domain. 

Image 7: Zaldua, Equisoain, Zabalza, Gonzalez & Marzo, 2016. Cell animal. Uploaded from Wikimedia Commons on 7/17/2016. https://upload.wikimedia.org/wikipedia/commons/9/9e/Cell_animal.jpg File used in accordance with the Creative Commons Attribution-Share Alike 4.0 International license.

Image 8: Madprime, 2016. DNA chemical structure. Uploaded from Wikimedia Commons on 7/17/2016. https://upload.wikimedia.org/wikipedia/commons/thumb/e/e4/DNA_chemical_structure.svg/800px-DNA_chemical_structure.svg.png File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license.

Image 9: Zephyris, 2009. DNA orbit animated static thumb. Uploaded from Wikimedia Commons on 7/17/2016. https://upload.wikimedia.org/wikipedia/commons/d/db/DNA_orbit_animated_static_thumb.png  File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license.

Image 10: Skovgaard, 2007. Boxer puppy fawn portrai. Uploaded from Wikimedia Commons on 7/17/2016. https://upload.wikimedia.org/wikipedia/commons/thumb/5/53/Boxer_puppy_fawn_portrai.jpg/1024px-Boxer_puppy_fawn_portrai.jpg File used in accordance with the Creative Commons Attribution 2.0 Generic license. 

Author: Maddie VanBeek

Think of all the different sizes, shapes, and colors you have seen represented just by looking at the moon. Just like trees change with the seasons, our moon kind of has its own little seasons! The moon takes about one month to rotate around Earth. Does it look the same every night? No! It undergoes a transformation! As the moon rotates, light is reflected more or less, depending on where the moon is positioned in relation to Earth and the sun.


When the moon is illuminated by the sun fully and the Earth is not blocking it, we see a full moon. This is when the moon looks like a perfect bright circle. When the moon is hiding behind the Earth and is hidden from the sun, we see a new moon. The moon is dark and difficult to see. In between the new moon and full moon, we see crescent moons, quarter moons, and gibbous moons. Waxing means the moon is getting larger and moving towards a full moon, and waning means the moon is getting smaller and moving towards a new moon.

Both of these Moon Phase raps will stick in your head and help you remember the moon phases!
 
Thanks, Flocabulary!

If you liked “Moon Phases,” check out Mr. Lee’s Moon Phases Rap for some more “out of this world” science raps!

Now that you know the phases of the moon, let’s further discuss eclipses.
Lunar eclipses occur when the sun, Earth, and moon are aligned in that order. Thus, lunar eclipses only occur during a full moon. The Earth blocks the moon from the sun’s light, and the Earth’s shadow, or umbra, is cast upon the moon. This shadow gives the moon a reddish glow. 

There are different types of lunar eclipses, including penumbral, partial, and total lunar eclipses.
In a partial eclipse, only a portion of the moon is shadowed by the Earth’s umbra, or shadow.

In a penumbral eclipse, only the outer part of the Earth’s shadow covers the moon, so the result is very subtle compared to the total or partial lunar eclipses. Below is an example of a penumbral eclipse (at the left)n as compared to the full moon one hour before eclipse (at right). At best, the moon just looks slightly shaded during a penumbral eclipse.

Finally, there is the total lunar eclipse. This gives the moon a reddish tinge and has been nicknamed a “blood moon.”   The image below was taken on April 15, 2014 in Minneapolis, Minnesota. 

Solar eclipses occur when the sun, moon and Earth are aligned, in that order. Solar eclipses can only occur during a New Moon. The moon blocks a portion of the sun’s light, so the Earth sees something like this: 

On October 23rd, 2014 there was a partial solar eclipse. This means that the sun and moon were slightly out of line, so the moon only obscured part of the sun’s light. Solar eclipses are much rarer than lunar eclipses. 

A total solar eclipse occurs when the sun and moon are exactly in line, and only a faint ring of light is visible around the moon’s shadow. The picture below is of a solar eclipse that occurred on July 22, 2009. This was the longest solar eclipse of the 21st century -- it lasted 6 minutes and 39 seconds! 

An annular solar eclipse is similar to a total eclipse in that it occurs when the sun and moon are exactly aligned, but the size of the moon appears smaller than it does in a total eclipse, so a brighter ring of light is visible around the moon. 

Why don’t lunar and solar eclipses occur with every Full and New Moon?
If the Earth and the moon orbited in the same plane, there WOULD be a lunar eclipse with every Full Moon and a solar eclipse with every New Moon. Because the Earth’s and moon’s orbits are off by about five degrees and the nodes move thirty degrees clockwise each month, the moon only aligns with the nodes (thus creating eclipses) about four to seven times every year.
 
Activity 1
Experience the phases of the moon!
 
You will need:

• A styrofoam ball
• A popsicle stick
• Clamp light

 
You will do:
1.Puncture the styrofoam ball with the popsicle stick.
2.The styrofoam ball represents the moon, you represent the Earth, and the clamp light represents the sun.
3.Clamp the light onto a wall or area taller than you, and turn the clamp light on.
4.Turn the room lights off.
5.Grasp the stick so that the styrofoam ball is held upright. Hold it out at arm’s length.
6.Start facing the clamp light. What do you see? The side of the ball facing you should be completely dark. Is this a new moon or a full moon?
7.Rotate counterclockwise. What happens to your “moon?”
8.Continue rotating and observe how the light/shadows change on your “moon.”
9.When you are facing directly away from the flashlight, what do you see? The side of the moon facing you should be completely illuminated. Is this a new moon or a full moon?
10. Rotate around one more time and identify points that you see a waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, waning crescent, and new moon.
 
Activity 2
Simulating Eclipses
 
You will need:

• Tennis ball (represents the Earth)
• Toilet paper roll
• Marble (represents the moon)
• Flashlight (represents the sun)
• String
• Tape
• Scissors

 
You will do:
1.Set the toilet paper roll on the table so that it is standing upright.
2.Set the tennis ball on top of the toilet paper roll (picture a scoop of ice cream on a cone).
3.Cut a piece of string (6 inches or so) and tape one end to the marble.
4.Set the flashlight on the table, facing the tennis ball.
5.Turn the flashlight on.
6.Position the marble so that it is directly in front of the tennis ball and in alignment with the flashlight. The order should be marble, tennis ball, flashlight. What kind of eclipse is this? Lunar or solar? Does the light reach the marble?
7.Position the marble so that it is directly in between the tennis ball and the flashlight. The order should be tennis ball, marble, flashlight. What do you see? What kind of eclipse is this? Lunar or solar? What would you see from Earth?
 


Image and video credits, in order of appearance
 
Andonee, 2015.  Diagram of Moon Phases.  Uploaded from the Wikimedia Commons on 7/10/2016.  https://commons.wikimedia.org/wiki/File:Moon_Phase_Diagram_for_Simple_English_Wikipedia.GIF File used in accordance with the Creative Commons Attribution-Share Alike 4.0 International license.
  
Flocabulary, 2014. Moon Phases.  Uploaded from YouTube on 7/10/2016. https://www.youtube.com/watch?v=xBc8QHSsFgE
  
Mr. Lee Science Rap, 2011.  Phases of the Moon Rap. Uploaded from YouTube on 7/10/2016. https://www.youtube.com/watch?v=79M2lSVZiY4&index=1&list=UU2DwkfiWSqRXxZ685AiFdGQ
  
Sagredo, 2008.  Geometry of a Lunar Eclipse.  Uploaded from the Wikimedia Commons on 7/10/2016. https://commons.wikimedia.org/wiki/File:Geometry_of_a_Lunar_Eclipse.svg  File released into the Public Domain.
  
Trouvelot, 1874.  Partial Eclipse of the Moon.  Uploaded from the Wikimedia Commons on 7/10/2016.  https://commons.wikimedia.org/wiki/File:Trouvelot_-_Partial_eclipse_of_the_moon_-_1874.jpg  Image is over 100 years old, and is in the Public Domain. 
  
Tomruen, 2014.  Lunar eclipse April 15 2014 Minneapolis Tomruen2.  Uploaded from the Wikimedia Commons on 7/10/2016. https://commons.wikimedia.org/wiki/File:Lunar_eclipse_April_15_2014_Minneapolis_Tomruen2.jpg.  File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license.

Sagredo, 2008,  Geometry of a Total Solar Eclipse.  Uploaded from the Wikimedia Commons on 7/10/2016.  https://commons.wikimedia.org/wiki/File:Geometry_of_a_Total_Solar_Eclipse.svg.  File released into the Public Domain. 
 
Clark, David.  View of Solar Eclipse and Building in Silhouette.  Uploaded from PublicDomainPictures.net on 7/10/16.  http://www.publicdomainpictures.net/view-image.php?image=148467&picture=solar-eclipse.  File released into the Public Domain. 
  
Nirjhar, Lutfar R., 2009.  Solar eclipse 22 July 2009 taken by Lutfar Rahman Nirjhar from Bangladesh.  Uploaded from the Wikimedia Commons on 7/10/2016.  https://commons.wikimedia.org/wiki/File:Solar_eclipse_22_July_2009_taken_by_Lutfar_Rahman_Nirjhar_from_Bangladesh.jpg  File used in accordance with the Creative Commons  Attribution 3.0 Unported license.
 
 Baird, Kevin; 2012.  Annular eclipse “ring of fire”.  Uploaded from the Wikimedia Commons on 7/10/2016.  https://commons.wikimedia.org/wiki/File:Annular_eclipse_%22ring_of_fire%22.jpg  File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license.
 

Author: Maddie Van Beek

​Everybody sweats. Whether you are hot, nervous, or working hard, you may notice your skin forming droplets of water, or perspiration. What happens to that perspiration after you sit for a few minutes? It vanishes! But do the water molecules really just disappear into nothingness? No, of course not! Although we may not see the water droplets any more, the water molecules have simply evaporated. Evaporation is just one of the steps in the water cycle.

When water evaporates, it changes from a liquid into a vapor. Therefore, evaporation is the process of water moving from the earth and into the air. One form of evaporation is called transpiration. While evaporation is the movement of water from the earth’s surface into the air, transpiration is the movement of water from plants into the air. Transpiration is kind of like a plant’s way of sweating.
Not only does transpiration cause plants to release water into the air, but it actually allows plants to absorb water from the ground through their stems. The water is transferred from the ground into the plant’s stem up through little tubes called xylem.  In the image below, the xylem tubules are shown in red.

Picture a bunch of minuscule straws sucking water out of the ground. This process delivers water and nutrients to the plant. The water travels up the xylem and leaves the plant through tiny holes called stomata. One of the stomata from a tomato plant leaf is shown below (they look like little mouths!).

Stomata may open or close to let gases in or out. For example, stomata open to take in carbon dioxide and let out oxygen. Unfortunately for the plant but luckily for us, stomata also releases water vapor. The number of stomata a plant has varies widely and depends on its environment. Trees in the rainforest have larger stomata that are open more often compared to the stomata of cacti in the desert. Trees in the rainforest need more water because they lose almost all of what they absorb, while cacti in the desert need less water, since they retain water for much longer. 

​Activity #1
How does the number of stomata influence a plant’s water loss? Let’s find out!
 
What you will need:
-Two cups
-A piece of 4x8 inch poster board
-Scissors
-Pencil
-A hole puncher
-Marker
-Tape
-Water
What you need to do:
1.Fold the piece of poster board in half.
2.Place one of the cups upside-down on top of the poster board.
3.Use your pencil to trace around the mouth of the cup.
4.Keep the poster board folded, and carefully cut out the circle you traced (You will have two identical circles).
5.Use the paper puncher to punch two holes in one of the circles.
6.Punch about twenty holes in the second poster board circle.
7.Fill both cups with equal amounts of water.
8.Use the marker to mark the water level on both cups.
9.Tape the circle with two holes across the mouth of one of the cups.
10. Tape the circle with twenty holes across the mouth of the other cup.
11. MAKE SURE the tape does not cover any of the holes, and check that the tape has secured the poster board to the edges of the cups.
12.Set the cups in the sun where they will not be disturbed.
13.Check your cups in three days.
 
Which cup has less water? Why?
 
Activity adapted from Transpiration: The Water Cycle in Plants posted on Education.com by Janice VanCleave.
 
Activity #2
Let’s find out how xylem work!
 
Have you ever seen those pretty rainbow-colored flowers? Where on Earth do these flowers come from?! Here’s the secret: They are dyed! The xylem in the stems help transfer the food coloring up the stems to the leaves of the flower. Try it out! 

​What you will need:
-A cup
-A piece of celery (or a white flower, if you have one!)
-A knife
-Blue or red food coloring
-Water
 
What you need to do:
 
1.Cut the bottom end off of a stalk of celery. Leave the leaves attached to the top.
2.Fill a cup with water.
3.Put about four drops of blue or red food coloring in the water. Make sure the color is rich and not too diluted.
4.Carefully place the celery, bottom end down, into the cup.
5.Leave the celery in the food coloring overnight.
6.If you started earlier in the day, check back every hour or so to record observations.
 
What happened to your celery?
 
How long did it take for the food coloring to start traveling up the stem? To the top of the stem? The leaves?
 
After the experiment is over, look at the bottom of the stalk. Can you identify the xylem?
 
 
 
 
Image and video credits, in order of appearance:
 
 
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. 
 
 
Kelvinsong 2013. Botana curus X xylem and phloem 400×. Uploaded from Wikimedia Commons on 7/3/16.  https://commons.wikimedia.org/wiki/File:Botana_curus_X_xylem_and_phloem_400%C3%97.png. File used in accordance with the Creative Commons Attribution 3.0 Unported license.

 
Photohound, 2007.  Colorized electron microscope image of a stoma on the leaf of a tomato plant.  https://commons.wikimedia.org/wiki/File:Tomato_leaf_stomate_1-color.jpg.  Image released into the Public Domain.
 
Runnels, Lisa.  Daisy Flower.  Uploaded from publicdomainpictures.net on 7/3/16.  http://www.publicdomainpictures.net/view-image.php?image=33863&picture=daisy-2.  Image released into the Public Domain.