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Photosynthesis: Floating Leaf Discs

3/14/2015

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Author: Maddie Van Beek

We all know that trees and plants make our world prettier and provide us with fruits and vegetables. But did you know that we actually NEED plants to live? Through the process of photosynthesis, plants take in the carbon dioxide that we give off and convert it to the oxygen that we desperately need to survive! How does this whole process work? 




This diagram explains the basic components of photosynthesis: 

Picture
http://www.cneccc.edu.hk/subjects/bio/album/Chapter8/images/PHOTOSYNTHESIS0.jpg
Plants not only need carbon dioxide, but also use water and sunlight to complete the photosynthesis process. 




Check out our blog on xylem to understand how water gets from the ground to the leaves of a plant:

Learn more about the details of photosynthesis!
Photosynthesis reaction equation:

Picture
http://www.lifeadrift.info/media/2316/photosynthesis_equation.jpg
This catchy song will help you remember the basics of photosynthesis!
Follow-up questions: 

  • What happens during photosynthesis? 
  • How is chlorophyll involved in photosynthesis? 
  • What do xylem do? 



Try defining this important vocabulary in your own words: 

  • Chloroplasts
  • Chlorophyll
  • Photosynthesis
  • Xylem



You now know everything you need to complete our basic photosynthesis experiment, but if you want to learn EVEN MORE, watch the video below!




This video explains the complexities of photosynthesis! You’ll know more than you ever wanted to know about how photosynthesis works. 

Activity



YOU WILL NEED:

  • Spinach leaves
  • Hole punch
  • Tweezers
  • 10cc syringe (no needle)
  • Water
  • Baking Soda
  • Soap


Here’s what to do!



If you like visual instruction, watch this video to see how to complete the experiment: 

  1. First, you need to create your bicarbonate solution. Do this by combining 1/8 teaspoon of baking soda with 1 and 1/4 cups of water. Stir the baking soda in until it is completely dissolved. 
  2. Next, use the hole punch to punch holes in your spinach leaves until you have about 20 spinach leaf discs. 
  3. Remove the plunger from the syringe, and place the spinach discs into the syringe. 
  4. Use the tweezers to push the discs down as far as they can go. Be careful not to crush or damage them. 
  5. Once you have all the leaf discs in the syringe, replace the plunger. 
  6. Put the tip of the syringe in the bicarbonate solution and pull back the plunger to suck up 10ccs of the solution. The baking soda solution is a source of bicarbonate ions, which is one source of carbon dioxide for photosynthesis.  
  7. Cover the end of the syringe with your finger, and then pull the plunger upwards as far as it can go to pull the air out of the leaf discs. Alternate pulling the plunger out and pushing it down (remember to keep the end covered with your finger the whole time to create a vacuum). Pushing the plunger down is forcing the bicarbonate into the leaf discs and pulling it up will remove any air from spaces in the leaves.
  8. Continue to do this until you see the leaf discs start to sink. Once all your leaf discs have sunk, squirt out the baking soda solution into a sink, making sure not to allow the leaf disks to plug the syringe.
  9. If you have trouble getting your leaf discs to sink, you can add a small drop of soap to the bicarbonate solution and try again. The soap makes the leaf less hydrophobic and will help it more easily absorb the solution.  
  10. Next, add more baking soda solution. You should suck up about 10 ccs, as you did in step 6.  Swirl your syringe around to make sure the leaf discs aren’t stuck to the sides or to each other. 
  11. Place your syringe upright in a well-lit area. Either artificial or natural light will work. 
  12. Wait to see how long it takes for the leaf discs to float. Record the time when the first disc rose to the surface. Wait until at least 5 leaf discs have risen back to the surface. Record the time it took for 5 leaf discs to float. If you are patient enough, record the time that it takes for all your leaf discs to float. What’s the point of this? You just watched photosynthesis occur!  The oxygen created inside the leaves by photosynthesis is making the leaves float again.  
  13. Practice making graphs! Create a line graph to show how long it took for the discs to float. I would put time along the x-axis and number of leaf discs along the y-axis. You could do this by hand, or you could use Excel to create it electronically. If you need help using Excel, refer to our blog on heart health for instructions. 







Follow-up questions:

  1. Would this experiment have worked with normal tap water? Why or why not?
  2. What was happening when the leaf discs sunk?
  3. Why did the leaf discs float at the end? 
  4. Create a diagram to show the steps of your experiment and how it relates to photosynthesis. 



If you had fun learning about photosynthesis, you might also like our blog on plant transpiration.



References:

  • <iframe width="560" height="315" src="https://www.youtube.com/embed/XV9FOWleErA" frameborder="0" allowfullscreen></iframe>
  • https://blog.udemy.com/photosynthesis-experiment/
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Learn about the different biomes!

3/8/2015

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Author: Maddie Van Beek

Did you know that we all live in a biome? A biome is a naturally occurring habitat with with a community of plants and animals. An example of a biome would be a forest. Think about the plants or animals that all forests have. What makes a forest a forest? You’ll find out today! Each biome consists of ecosystems whose members have specially adapted to the climate and environment of the biome in which they live. For example, cacti are able to go long periods of time without rain, which allows them to survive in the desert.  



Biomes differ in many different characteristics, such as their land forms, amount of precipitation, and sunlight, to name a few! Your job today is to determine the unique characteristics of each biome. 



There are five main types of biomes, including 

1. Aquatic

Picture
http://media.opencurriculum.org/articles_manual/ck12_biology/aquatic-biomes/7.png
2. Desert
Picture
http://www.london.d21.k12.il.us/teams/6discovery/DBalbum/images/desert1_jpg.jpg
3. Forest
Picture
http://cf067b.medialib.glogster.com/media/a7/a7165c78951c4b243304f1de98c2541cf0dabd5a3dc599f93583244883950b47/10-rainforest.jpg
4. Grassland 
Picture
http://education.seattlepi.com/DM-Resize/photos.demandstudios.com/getty/article/178/196/78391368.jpg?w=600&h=600&keep_ratio=1&webp=1
5. Tundra
Picture
http://bioexpedition.com/wp-content/uploads/2012/04/Tundra-picture.jpg
These main biomes can then be divided into different subtypes. For example, the aquatic biome is split into freshwater and marine. All of the biomes are categorized as either an aquatic biome or a terrestrial biome. 



Check out this link to learn more about the five major types of biomes: 

Five Major Biomes
Use the following resource to find out all the different subtypes of the five main biomes: 

Biome Subtypes
Here’s an example of how the world is split up into different biomes:

Picture
http://media.maps101.com/SUB/earth_science/B_World_biome.gif
What biome covers most of the world? Least?



Create a visual to show the different subtypes of the main biomes. Yours might look something like this:

Picture
http://www.oconee.k12.ga.us/~pwilder/biology/Ch.3-4%20Ecology/Organizer%20Ch.3-4/MajorBiomes2.jpg
After you have researched the different biomes and their subtypes, record important information. A great way to organize all your information would be to make a chart, like this one:

Picture
http://media-cache-ak0.pinimg.com/236x/f4/1f/5b/f41f5b5d829378c1746f3c1141630e73.jpg
Questions to consider: 

  1. Where is this biome found? 
  2. What kinds of plants grow there?
  3. What are the precipitation and temperature like?
  4. What kinds of animals live in this biome?
  5. What adaptations do the plants/animals/people have to have to live here?



Play this “build your own biome” game to test your knowledge about biomes!

Organize the biomes from driest to wettest. You could use the graphic organizer below. 

Picture
http://freeology.com/wp-content/files/blanktimelineblack-thumb.png
Follow-up questions: 

  • Why might the amount of precipitation matter? 
  • How would different levels of precipitation affect the characteristics of the biome? 
  • What might change in a biome if the temperature changed drastically?
  • Now that you know a little bit about biomes, what kind of biome do YOU live in? 



ACTIVITY: BIOME IN A BAG



YOU WILL NEED

  • Potting soil
  • Gallon Ziploc bags
  • Seeds (bean seeds usually work well)
  • Pebbles
  • 2 liter soda bottle with the top cut off
  • Water



HERE’S WHAT TO DO!

  1. Have an adult help you cut the top off of a soda bottle. 
  2. Pour some pebbles into the soda bottle until they are about 1/2 inch deep. 
  3. Pour about one inch of potting soil on top of the pebbles.
  4. Plant the seeds. Use your finger to create a small trench in the soil, then sprinkle a pinch of seeds into the trench. 
  5. Carefully smooth the soil over the seeds.
  6. Pour water into the soil until you see it reach the bottom of the pebbles. 
  7. Being careful not to spill, place the entire soda bottle (your biome) into a gallon plastic bag and seal the bag. 
  8. Place your biome in the sun where it will get plenty of nutrients. 
  9. Now, wait! Because your bag is sealed, you have created an environment for your plant to grow. The water that you poured into the soda bottle will evaporate, condense, and precipitate without escaping the bag. Can you believe the water cycle can take place in such a small area?!
  10. Now that you’ve made one biome, follow steps 1-9 to make a few others, but use varying amounts of pebbles, soil, or water. You could also choose to give certain biomes more or less sunlight. Try to create environments that imitate the biomes you learned about and make predictions about which biomes will grow plants more successfully. 



References: 

  • http://pbskids.org/zoom/activities/sci/biomeinabaggie.html
  • http://www.switcheroozoo.com/games/habitatgame.htm
  • http://www.blueplanetbiomes.org/world_biomes.htm
  • http://en.wikipedia.org/wiki/Biome
  • http://www.ucmp.berkeley.edu/glossary/gloss5/biome/
  • http://kids.nceas.ucsb.edu/biomes/
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How much sugar is in your favorite can of soda? 

3/1/2015

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Author: Maddie Van Beek

Sugar is equal to ENERGY, right?! Not quite. Although a lot of people out there think that an excess of sugar gives you a “sugar high,” or makes you extremely hyper, did you know too much sugar actually makes you feel tired? 

Picture
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRSIcnBgv_5wTlrVdiJwR2bVhD77ih74ymMNKl7cmyobVtf6Yyo
When you consume an abundance of carbohydrates, your body produces insulin, which triggers your tissues to use up the glucose, which then causes your blood sugar levels to CRASH. This is no fun!


What are the symptoms of a sugar crash?

Sugar Crash
Check out this video for an explanation of why sugar does NOT cause hyperactivity!

Here’s a diagram that explains what your body goes through when you eat too much sugar: 

Picture
http://www.womenshealthnetwork.com/images/articles/SugarRollerCoaster.jpg
What IS sugar, anyway? The sugar that you see in your cupboard is refined from sugar cane or sugar beets. Sugar is the household name for these kinds of short-chain, soluble carbohydrates composed of carbon, hydrogen, and oxygen. There are actually a few different types of sugars: monosaccharides (glucose, dextrose, fructose, and galactose) and disaccharides (sucrose). 



Sugar molecule: 

Picture
http://2.bp.blogspot.com/-PQdLqg8mywE/UFKPIiXERMI/AAAAAAAAFc8/BXftMkRsVWs/s400/sugarmolecule2.gif
Where else might we find sugar? Not just in sugarcanes and sugar beets! Sugar appears naturally in fruits and other plants. Sucrose is what we commonly use as table sugar, while glucose and fructose are found in fruits and plants.



Yes, we do need some amount of sugar to keep our bodies running. The problem with sugar is that people these days eat TOO MUCH of it. While it is definitely okay to eat foods with natural sugars such as fruit or indulge in your favorite ice cream or candy once in a while, watching your sugar intake could help you lead a healthier, more enjoyable lifestyle! 



Why? An excess of sugar could increase your risk of obesity, diabetes, and tooth decay. Cutting back on your sugar intake may help you avoid these risks. Some people even feel addicted to sugar. The more you eat sugar, the more you crave it.

Picture
http://www.intheequation.com/wp-content/uploads/2013/06/sugar-addiction-perpetual-cycle.png
The key to cutting back on sugar is understanding the amount of sugar you are taking in and how much sugar certain products contain.



How much sugar is in your favorite soda? Drinking less soda is a great way to lower your sugar intake. Everyone knows that soda has a lot of sugar in it--but just how much sugar are we talking? Let’s find out!



YOU WILL NEED:

  • Can of soda
  • Pot
  • Stove
  • Adult
  • Teaspoon



HERE’S WHAT TO DO!

  1. Pour a 12-oz can of your favorite soda into a pot.
  2. Put the pot on a stove burner. 
  3. Turn the stove burner up to medium heat. 
  4. Let the soda boil. Once the water has evaporated, you will be left with a gooey substance. That gooey syrup is the sugar!
  5. How much sugar is there? Measure it out with a teaspoon. 
  6. You should have discovered that there were about 7-8 teaspoons of syrup left after the liquid in the soda evaporated. Jeez, that’s a lot of sugar!
  7. Try dissolving 2 teaspoons of sugar into a 12-oz glass of water. Can you taste the sugar? Now, try dissolving 7 teaspoons of sugar into a 12-oz glass of water. You’ll be amazed at how sweet it tastes! Can you believe one can of soda has that much sugar?!
  8. Try this same experiment (steps 1-5) with other drinks! Boil down fruit juice or other sodas with different amounts of sugar. Which drink had the most sugar? 
  9. Make a chart to track which drinks have the most sugar. 



In case you need help, here’s a video example of how you might complete this experiment! (He uses a scale to measure the sugar, which we didn’t use today. If you have a scale at home, you could certainly use it!)

For other ways to learn about your health, check out our blog on heart health (http://discoveryexpress.weebly.com/homeblog/why-is-heart-health-so-important) or our Thanksgiving blog on serving sizes (http://discoveryexpress.weebly.com/homeblog/happy-thanksgiving). 




References: 

  • http://en.wikipedia.org/wiki/Sugar
  • http://sugarcrash.org/sugar-crash-symptoms/
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Our new books are now available!

3/1/2015

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We now offer books of lessons for elementary and middle school, aligned to both the Common Core and Next Generation Science Standards!  Included in each are simple explanations of important science concepts, as well as easy to follow step by step instructions for a fun hands on activity to demonstrate the concepts learned.  Available as both a digital download or paperback book, get them here today!
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