Welcome to science second semester. My name is Mrs. Datta and I will be the long term substitute for Ms. Uemera until she returns. I have been a middle school science teacher for 30 years, of which 25 years were in 8th grade at AES. I am happy to be back in the classroom and a part of your learning journey.

The Units we will be studying are the following:

Matter and Energy in Organisms and Ecosystem

Earth’s Systems

The standards for this unit are:

Recognizes how matter becomes part of living things.

Understands the process of photosynthesis and energy flow through living systems.

Follows matter (carbon and oxygen ) through the earth cycles

Relates solar energy to movement of matter

As always, our units will be rooted in inquiry based learning. A broad focus would be to have you learn how to:

ask questions and define problem

analyze and interpret data

develop and use models

construct explanations and design solutions

obtain, evaluate and articulate findings from investigations and other sources

communicate scientific ideas in multiple formats

Please keep your lab notebook up to date along with the activities on google classroom. These will be used formatively.

Introduction to Earth Cycles- Carbon and Water

Cycles of a living planet
The Earth is a dynamic planet. Geological and biological processes cause energy and the elements necessary for life-carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus- to circulate through global “reservoirs.” These reservoirs are the biosphere (the living portion of our planet), the atmosphere, the ocean, and the solid Earth. It is only because of this cycling that life can thrive. The cycling of elements determines the environment, for example by regulating the composition, and thus the temperature, of the atmosphere.

Elements that sustain life stay in the Earth’s reservoirs for different lengths of time. Carbon in the form of coal or carbonate rocks may remain in the solid Earth for millions of years, but as carbon dioxide it stays in the atmosphere for only a few years. The amount of material transferred between reservoirs can be enormous. The uppermost meter of the entire ocean evaporates to the atmosphere every year, to be returned as rain or snow. This transfer is one of the most important factors controlling climate.Carbon is a major component of all life, and in the form of the greenhouse gas carbon dioxide, it helps to maintain a habitable range in temperatures. Carbon moves through all the Earth’s reservoirs. Most of it is contained in sedimentary rocks: coal, chalk, lime-stone, and shale. But carbon in sedimentary rocks, with an average residence time of 400 million years, participates little in global carbon circulation over shorter times. The average residence times of carbon in the atmosphere (5 years), the biosphere (13 years), and the oceans (350 years) are much shorter.

Read the article below and go through the 2 links on carbon dioxide. Answer the following questions in your notebook about what you read.

What are the big ideas?

What are 3 significant details?

What did you not know before?

What is the importance or relevance of the big ideas and the significant details?

How did what you read connect with what you learned about photosynthesis and the significance of this process for earth cycles?

Introduction to the carbon cycle

2015 Begins with CO2 above 400 PPM Mark


Water is part of the Earth, its atmosphere, and all of its living organisms. As the chief force responsible for weathering and erosion, it shapes the surface of our planet. Water travels from ocean to atmosphere by evaporation, and from atmosphere to ocean by precipitation. The circulation of water from one reservoir to another consumes or releases energy, moderating the Earth’s temperature.

March 16-22 Summative Photosynthesis

Photosynthesis argument and evidence

  • Display and use the basic simplified claim showing the role of water and carbon dioxide and the production of glucose, oxygen, and new water in photosynthetic organisms.
  • Include information about the site of photosynthesis in photosynthetic organisms.
  • Link firsthand (our activities and experiences) and secondhand (historical experiments and evidence)
  • Include visual representation of claims of photosynthesis (captioned/labeled)
  • Discuss that the simplified claim does not reveal the complex series of reactions involved in photosynthesis. While all the details of these cycles of reactions need not be shown, better projects will mention some of the historical experiments and evidence that have led to understanding of the cycles.
  • Each claim linked with firsthand or documented evidence
  • Must address claims of energy input and output
  • Must address claims of flow of matter
  • Written section explaining how PS Standards from 3 strands are met
  • SEP
  • Analyzing and Interpreting Data
  • Engaging in Argument from Evidence
  • CCC
  • Structure and Function
  • Stability and Change
  • DCI
  • M and E in organisms and ecosystems
  • Earth Systems


  • Illustration(s) (not poster size)
  • Poster
  • Slide show
  • sketches and photos / models / something original (you can justify the originality)
  • other—with approval


  • visual (original) representation of claim (accurate–well-done)
  • 3 first hand pieces of evidence–clearly and correctly linked
  • 3 historical pieces of evidence–clearly and correctly linked
  • not all supporting the same part of the claim
  • missing evidence is indicated (what else is needed to establish the claim)
  • discussion of how the claim is simplified
  • Due March 22,23 You will be presenting your project to the class.

Please work on this on your own time during the weekend to make sure the project is completed on time.


https://www.youtube.com/watch?v=TWO9YzAvIDg New Water

https://www.youtube.com/watch?v=cVDpdmlpZKw  Video on the history of plants

https://www.youtube.com/watch?v=QkPJzK9SnTg Testing for starch in leaves for photosynthesis

https://www.youtube.com/watch?v=x17XhQJ3PxI chlorophyll is necessary for photosynthesis

https://www.youtube.com/watch?v=kKMNig0Cz04 BBC Blooming History of plants



https://www.khanacademy.org/science/biology/photosynthesis-in-plants/the-light-dependent-reactions-of-photosynthesis/a/light-and-photosynthetic-pigments affect of pigments on photosynthesis

http://hyperphysics.phy-astr.gsu.edu/hbase/Biology/enercyc.html#c1 energy cycle in plants


March 6,7-Leaf shape,Transpiration and Photosynthesis

Measuring Transpiration of the 4 leaves

Today we will go and gather the results from the leaf experiments set up during last class.

First, carefully remove the plastic bag that was covering the leaf. Do not spill any water. Very carefully measure the water in ml of all the 4 leaves (top, bottom, top and bottom covered with vaseline and original leaf(without vaseline) (Read the cylinder carefully. You might want to empty the bag into a beaker and then pour the water from the beaker into the cylinder. If your bag did not collect any water, the most likely reason is that the bag was not sufficiently closed. Transpiration involves evaporation at the leaf surface. You might imagine it is a complicated process for water to move into the roots and up the plant into the leaves. Some of the water is used for photosynthesis. The water in the plant also gives it turgor and dissolves various molecules that are transported in the plant. There is no pump for this circulation (like a heart in animals) but rather a complex interaction of physical processes “managed” by the plant. To get a “taste” of the coordination of processes, browse this article:

Lay the leaf that was in the bag flat on some 1 cm x 1 cm graph paper. Trace the outline. Estimate the surface area. (Both partners estimate and then compare. You should be close to each other.) Can do this for all the 4 leaves.

We will collate the data and make a scatter plot with volume of transpired water on the vertical (y-) axis and surface area of leaf on the horizontal (x-) axis. Be sure to title graph, label axis with variable and unit, choose convenient, consistent scales that includes all the data and covers 1/2 the graph paper. We will see if there is a relationship between the area and transpired water by the leaf.


After doing the surface area of each leaf, on the “how plants breathe sheet” write your observations of the leaves that had vaseline on them. Also note the amount of transpiration in the bag of those leaves that had vaseline on them. Describe what you see and explain what happened and why do you think the leaf is the way it is.

Parent Teacher conference Prep

Make a plan for what and how you are going to show your work during the upcoming parent conference. Work you are proud of, examples of real learning, things that have stimulated your thinking, challenges–concepts, science practices/skills, work habits, focus, perseverance, what you want to work on to meet/overcome challenges, your thoughts on being ready for high school science, your longer-term educational ambitions.

If you have any really nice pictures or drawings that you have taken or made this year in science, share them, and let’s get them nicely printed and mounted. Perhaps we can have a showing.


Feb 27-March 3 Photosynthesis Activities, Experiments and Gathering Evidence

1. You will be growing your own seedlings and performing an experiment with the presence/absence of specific plant
requirements to observe their effects on growth. Once the plant is grown to a certain size ,we will be ready to experiment and see the affect of certain factors on plant growth. You will be choosing the factor that you want to investigate later in this week. Follow the instructions below. You will be working in groups of 3’s. Choose your partners.
Planting kidney beans in Soil
a. Fill 3 plastic cup most of the way with potting soil and plant 5-6 beans. Cover the seeds gently with soil.
b. Moisten the soil. Put about 50ml of water in each of the cups.
c. Label your cups. Put plastic wrap over the cups and place them in the tray labeled for your class.(The plastic wrap will help the soil stay moist. Remove the plastic when seedlings appear.)
d.    You will check on the beans in your cups each day you have class. Make a data table in your notebook to record your observations on days you have class.You will need this when we start experimenting on the seeds two weeks from now. Read about some factors  (link below) which affect plant growth and think about which one you would like to investigate once the seedlings are grown. You may choose from light, temperature, or water. We will not be doing different soils. Jot that factor down in your notebook.

Factors which affect plant growth

2. Check vaseline leafs and transpiration. Record observations on the sheet given in class on friday. Keep the sheet until Friday. Will turn it in after few more observations.

3. Read the attached information on photosynthesis and do the worksheet in your notebook.

4. Watch attached video on Plants in Action when completed all of the above. Use headphones when viewing. Summarize in a paragraph what you learned from this video that enhanced your understanding of photosynthesis and the importance of plant in the earth cycle. Write this in your notebook.

5. If time permits look  and play the interactive below(NOVA series) on how the oxygen and carbon-dioxide cycles are dependent on each other.

6. Enhance your knowledge by reading the link below as to why leaves are not black? Follows the video I will be showing in class.

Nova series-photosynthesis

photosynthesis worksheet

Plants in action- Photosynthesis https://classroom.google.com/c/MTkwMDA0NjczM1pa

http://hyperphysics.phy-astr.gsu.edu/hbase/Biology/ligabs.html#c2 Why do only plants photosynthesize and why are leaves not black?

Feb 17, 22 Photosynthesis-Evidence and Claims



Your understanding of the claim–so far?

Your understanding of the evidence supporting the claim–so far?

What’s left to figure out?

There are many steps in photosynthesis. The simplified “claim” is over-simplified. (The dilemma of detail in teaching and learning science–how are you affected?)

Scientists have delineated two sets of reactions in photosynthesis. In one water is decomposed and the oxygen is released. Light is needed for this reaction. Hope you wonder how that happens? How then does that reaction interact with a second where carbon dioxide is fixed into larger and larger molecules? The simplified claim uses glucose to represent a balanced outcome. In the actual process, the glucose units are “stored” in much larger molecules of starch. There are other molecules which uses bonds with phosphorus to store energy. In a way, photosynthesis involves carbon dioxide and water (and other reactions) to make the two kinds of food: building material and fuel. The fuel is chemical energy that has been transformed from the energy of sunlight.

Where does the oxygen released by plants during photosynthesis come from? Follow the logic and evidence of another famous set of experiments conducted at U Berkeley with radioactive isotopes:




Look at the stomata taken from the underside of the leaf of a bryophyllum plant, tradescantia plant and the Lily below done by the grade 8 students in science class.

How Plants Could Impact Global Warming

Feb 10,13 Claims, Evidence and Arguments Photosynthesis

Examine the online textbook E.O. Wilson’s Life on Earth. Download  and examine those sections that you think are relevant to photosynthesis and understanding the flow of matter and energy involving life on earth. (Add what you think are the important words to your word list. Read short passages. Do not read so much that you feel overwhelmed. Summarize in writing what you get from a passage. Write down the questions that you have.)




How do you think scientists have come to the conclusions they have about photosynthesis? How do they know?

What do you think constitutes the evidence for the following simplified versions of photosynthesis? (What is the difference between the two versions?)





The overall equation for Photosynthesis is

6 CO2+ 12 H2O + light–>C6H12O6 + 6 O2 + 6 H2O

The equation in words says that six molecules of carbon Dioxide plus twelve molecules of water in the presence of light will make one molecule of glucose, six molecules of oxygen gas, and six molecules of water.

Where do you think the released oxygen comes from–the carbon dioxide or water? See if this animation helps you figure out the answer. Notice that the equation in this animation includes 6 more water molecules. Why do you think this is the case? Try the experiments, take the quiz.


See how this teacher has tried to explain photosynthesis to his students:


  • What is the point?
  • How well does it work? What questions do you have?
  • What confusions might arise? How? Why?
  • What misconceptions might develop? How? Why?

Historical timeline of photosynthesis histphoto

  • How many scientists and how many years did it take to arrive at the claim of photosynthesis?
  • 6CO+ 12H2O ——> C6H12O+ 6O+ 6H2O
  • Many intermediate reactions and reaction cycles–one set decomposes water and one set builds simple carbon compounds–energy driving these reactions comes from sunlight

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Feb 3, 8 Properties of Light

Were you ever scared of the dark? It’s not surprising if you were, or if you still are today, because humans are creatures of the light, deeply programmed through millions of years of history to avoid the dark dangers of the night. Light is vitally important to us, but we don’t always take the trouble to understand it. Why does it make some things appear to be different colors from others? Does it travel as particles or as waves? Why does it move so quickly? Let’s take a closer look at some of these questions—let’s shed some light on light!

What are your ideas about energy?

  • Individually, write 3 true and important statements (subject and predicate) about energy.
  • Individually, write 3 examples illustrating your true and important statements.
  • Compile list in your group of statements and examples.
  • Include questions.
  • Important scientific ideas

Light as a significant form of energy

Properties and behavior of light–several demonstrations

It is very important today to observe carefully, to listen closely to the discussion, to record your thoughts, ideas, and questions, to take picture of the various phenomena, and to continue your inquiry into the nature of energy and light.

Read the article below to get more information about what is light and the properties of light:



Energy and Work in Living Systems

Waves (see board diagrams and demonstrations with “slinky.”)


30,31 January Yeast Fermentation

Earlier in the year we talked about how food is both fuel and building material. In our study of matter, we looked at the conservation of mass. This meant taking the atoms at the beginning of a reaction and seeing how they are transformed into products at the end of the reaction. Every living thing takes in matter and gives out matter in a different form. In the process energy is also transformed. See the scientific claim about how a molecule whose bonds store energy is used by yeast and is then transformed into products which are expelled from the cell. Pay close attention to the reaction equations.

  • Sucrose is converted to 2 molecules of glucose/fructose.
  • C12H22O11 + H2O + invertase → 2 C6H12O6
  • Glucose/fructose is converted to 2 molecules of ethanol and 2 molecules of carbon dioxide.
  • C6H12O6 → 2 C2H5OH + 2 CO2

Make up a solution of 80 grams of sugar (sucrose) in 200 ml water at 40 degrees Celcius.

In both the flask and the bottle, put 200 ml. of this solution.  Add 1/2 pkg yeast. Stir and attach a balloon to the bottle and a stopper and tube to the flask. Fill the tube 1/2 way with limewater and cover the limewater with a very thin layer of oil (to make a barrier with the atmosphere).

Note: Limewater is an indicator of carbon dioxide. (Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2O(l)) (aq means aqueous or dissolved, g means gas, s means solid, l means liquid)

Observe. Watch the time and see what changes take place. Look at the rate of bubbles. Look at the volume of the balloon. How do you think yeast reproduce? How do you think the rate of reproduction relates to the rate of fermentation or rate of the overall reaction changing sugar to ethanol and carbon dioxide?

When ready, we will take off the balloon and put a drop of solution on  a slide. Cover the drop with a coverslip. Examine under low power first. Then examine under medium power. Try to stain a drop of the solution. Sketch some sample yeast cells. Every living thing is made of cells. The transformations of matter and energy take place the cells of living things. Think of the magnitude of living cells on the earth and how the cumulative activity affects the chemistry of the earth.

See the following link to *Lives of a cell* by Lewis Thomas. This is a significant example of science writing for the general (educated) public. Pick out one of the chapters to read. Be prepared to share your reading through an annotation: description, summary, assessment, reaction.