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Photosynthesis involves three elements: carbon, hydrogen, and oxygen. You have seen that the products of photosynthesis are oxygen and glucose. Their chemical.
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7 th^ Grade Science- Week 2
Complete the following assignments for week 2.
Week Topic/TEKS Agenda
Photosynthesis
7.5(A) recognize that radiant energy from the Sun is transformed into chemical energy through the process of photosynthesis
1. Video: Photosynthesis - Watch this video for an introduction to Photosynthesis - https://youtu.be/UPBMG5EYydo - 2. Reading Photosynthesis - Read the article. While you read, complete the Linking Literacy: Categorize Words - After you read, complete Linking Literacy: Box it. 3. Practice: CLOZE-ing in on Science - Use the word bank to complete the paragraph. 4. Math Connection: Photosynthesis - Analyze the data table and complete the graph and questions. 5. Reading in Science: Thanks, Leaves! - Read and annotate the text and answer the questions. 6. Claim-Evidence-Reasoning - Read the scenario and complete the CER. 7. Assessment: Photosynthesis
We can observe photosynthesis using a simple experiment. Photosynthesis is a chemical process. Because this process takes place at the level of molecules and atoms, we cannot observe it directly. However, we can observe the results of photosynthesis.
Joseph Priestley was one of the first scientists to observe a product of photosynthesis. He ran an experiment in which he placed a burning candle and a mouse under a glass dome. After a few minutes the flame went out. Priestley showed that the gases in this dome could not keep the mouse alive. However, if the experiment was repeated with a plant present under the dome, the mouse remained alive. What change had the plant made to the dome?
The plant replaced the oxygen that had been used up by the burning candle. Oxygen is a colorless, odorless gas that humans cannot observe directly. However, its presence is required for animals such as mice to live. Priestley demonstrated that the plant could produce oxygen. Oxygen is one of the products of photosynthesis.
Photosynthesis involves three elements: carbon, hydrogen, and oxygen. You have seen that the products of photosynthesis are oxygen and glucose. Their chemical formulas are shown below. What elements make up these molecules?
The process of photosynthesis is actually a complex series of many different chemical reactions. The equation shown above represents the overall reaction. Only the beginning and ending chemical compounds are shown in this equation. There are many more steps in between.
Only three elements are present in the products of photosynthesis: oxygen, carbon, and hydrogen. These same elements are present in the reactants of photosynthesis.
Products of Photosynthesis Name: Oxygen Glucose Chemical formula:
Reactants of Photosynthesis Name: Water Carbon dioxide
Chemical formula:
Photosynthesis involves water and carbon dioxide reacting to form oxygen and glucose. The chemical equation showing this process is: Radiant energy 6H 2 O + 6CO 2 6O 2 + C 6 H 12 O 6
Notice that it takes six molecules of water and six molecules of carbon dioxide to make one molecule of glucose.
The inputs and outputs of photosynthesis are shown in the diagram at right. Carbon dioxide in the air enters a plant through its leaves. Water in the soil enters through a plant’s roots. Oxygen exits from the leaves. Glucose stays behind to serve as the plant’s food.
These fuels would not contain glucose, but they would contain other carbon-containing compounds. Such biofuels have been produced from corn, sugar cane, soybeans, and sunflowers.
To make biofuel from cyanobacteria is not hard to do. However, the process is expensive. Right now it costs too much to develop biofuel from the strains of cyanobacteria available. Each cell produces a very small amount of the compounds that serve as the raw material for biofuel production. It is also costly to provide the large quantities of water needed to grow the microorganisms. In all, the cost of making the biofuel is greater than the price at which the fuel can be sold. Much research is being done to find ways to bring costs down so that the process is economical.
What do you know?
Read the following statements below. Fill in each blank with the correct word from the following list: Sun, photosynthesis, radiant energy, food, chemical energy, water, glucose, carbon dioxide, oxygen.
The main idea is recorded in the center circle. Use the boxes to record details and facts about the topic. Use the space below to record additional notes.
Box It
Photosynthesis Post-Reading Activity
Photosynthesis
Photosynthesis Matter and Energy
INSTRUCTIONS : Use the words in the box below to fill in the blanks based on what you have learned about photosynthesis. Words may be used more than once or not used at all.
atmosphere light change energy storing plants Earth’s substances evidence oxygen process water glucose
CLOZE 1
The Sun radiates energy toward _____________ surface, and some of this radiant energy is in
the form of _______________. Photosynthesis is the _______________ of converting
______________ energy into chemical energy and _______________ it through the bonds of
sugar. This chemical process occurs in _________________. During photosynthesis,
______________ from the Sun, carbon dioxide from the _______________, and
________________ absorbed from the soil are transformed into chemical _______________.
This chemical energy is stored in the form of a sugar also known as _______________. During
this process, ____________ is produced and released into the atmosphere. The importance of
photosynthesis lies in the fact that the _____________ stored in plants is what sustains life on
Earth.
Word Bank
Photosynthesis (A) Matter and Energy
Photosynthesis is a chemical reaction that occurs in plants by using radiant energy from sunlight. In this chemical reaction, carbon dioxide from the atmosphere and water from the soil are combined to produce sugar (glucose) that contains stored chemical energy.
A science class conducted an experiment to test the effects of artificial light on a plant’s rate of growth. All plants used for the experiment originally measured 5 cm in height. Throughout the three week experiment, each plant received the same amount of water and time under its assigned wattage of light each day.
Hypothesis: Plants exposed to brighter light will experience a higher rate of growth through photosynthesis than those exposed to dim light.
Effects of Light Intensity on Plant Growth
Plant A ( watts)
Plant B ( watts)
Plant C ( watts)
Plant D ( watts)
Week 1 5.5 cm^ 6.4 cm^ 6.8 cm^ 7.5 cm
Week 2 6.0 cm^ 6.8 cm^ 7.2 cm^ 8.0 cm
Week 3 6.2 cm^ 7.2 cm^ 7.5 cm^ 8.8 cm
Photosynthesis (A) Matter and Energy
Plant A: _________ Plant B: ________ Plant C: ________ Plant D: ________
Key ❑ Plant A ❑ Plant B ❑ Plant C ❑ Plant D
Week 1 Week 2 Week 3
2 Which is the best summary of the selection?
A Leaves are something to be thankful for because they produce carbohydrates.
B Leaves conduct photosynthesis, which converts energy from the Sun into chemical energy that is useful and important to humans.
C Photosynthesis is a vital part of the food chain.
D Radiant energy is the most important part of photosynthesis. It is energy from the Sun, which leaves are thankful for.
1 In paragraph 1 of this passage, which clues help you figure out the meaning of the word vital?
A “Changes this energy”
B “Captured from the Sun”
C “Chemical change called photosynthesis”
D “Need them to survive”
Photosynthesis (A) Matter and Energy
3 The above flow chart traces the energy transformations for the process described in paragraph 3. Which of the choices below in the order of (1), (2), (3) will correctly fill the blanks in the chart?
A Heat, Chemical, Light
B Heat, Light, Chemical
C Light, Chemical, Heat
D Chemical, Heat, Light
4 How is ethanol made?
A By fermenting sugars and starches
B By composting grass cuttings and dinner table scraps
C By boiling water and corn oil
D By releasing carbon dioxide into the atmosphere
Photosynthesis (A) Matter and Energy
Scenario
Below is the equation of photosynthesis. Photosynthesis is a process that takes place in plants. Notice that C0 2 and water are converted into sugar and oxygen.
External Data
When you go home tonight, your mother asks you to explain to her what happens during the process of photosynthesis. Your mother is a science teacher, so make sure you use scientific terms to give her a scientific explanation of how energy is stored as sugar in plants through photosynthesis.
Claim:
Evidence:
Reasoning:
Rebuttal:
Photosynthesis Matter and Energy
Photosynthesis Matter and Energy
Photosynthesis CER Rubric for Writing a Scientific Explanation
Points Awarded 2 1 0
Claim Claim is complete and accurate.
Claim is incomplete or inaccurate.
Student does not make a claim or does not answer the question.
Evidence Evidence cites data and patterns within the data and uses labels accurately.
Evidence cites data from the data source but not within the context of the prompt.
There is no evidence, or changes are cited but do not use data from the data source.
Reasoning Student cites the scientifically accurate reason using correct vocabulary, connects the reason to the claim, and shows accurate understanding of the concept.
Student cites a reason, but it is inaccurate or does not support the claim. Reasoning does not use scientific terminology or uses it inaccurately.
There is no reasoning, or student relies on a restatement of the claim.
Rebuttal Rebuttal provides reasons for different data or outliers in the data, offers relevant real-world cases, or suggests other uses for the findings.
Rebuttal is not connected to the data, or it is not accurate.
Student does not offer a rebuttal.