Making Oxygen Through Transformation of Energy

An Investigation of the Photosynthesis Chemical Process Using Algae

Jul 5, 2009 David R. Wetzel

Students use inquiry-based thinking and science process skills to investigate chemical reactions that produce oxygen based on experimental findings and conclusions.

Students study that the transformation of energy occurs in many forms, including transforming energy from the sun to make oxygen though photosynthesis. This is a chemical energy transformation process which occurs as sunlight interacts with the chlorophyll in green plants to produce oxygen. Plants, such as algae, use leaves as solar collectors to collect energy from the sun.

As water from roots and carbon dioxide from the air enter a leaf, sugar and oxygen are created through the photosynthesis chemical process. As a point of reference, six molecules of carbon dioxide and six molecules of water produce one molecule of sugar, along with six molecules of oxygen. For the purpose of this science investigation the sugar is ignored, because the focus is on making oxygen.

Investigating Algae’s Ability to Make Oxygen

This experimental findings and conclusions are designed to prove that green plants, algae in this case, transform the energy of sunlight into oxygen.

Materials: (per group)

• 1 – 500 mL Beaker or similar size clear glass jar
• 1 – 250 mL Beaker or similar size glass jar
• 1 – Clear Glass Funnel (fits inside glass jar)
• 1 – Test Tube (fits over spout of glass funnel and longer than funnel spout)
• 2 – Pieces of Small Glass Tubing
• 1 – Small Scoop
• 1 – Grease marker
• Metric Ruler
• Algae
• Water
• Digital Camera

Procedures:

1. Place small glass tubing pieces across bottom of beaker.
2. Place algae in the center bottom of the beaker using small scoop.
3. Place the funnel in the beaker; spout up, so that funnel covers the algae. Ensure the glass rods are positioned in such a manner that the funnel is perpendicular to the beaker bottom.
4. Very slowly pour water into the beaker until it is within two centimeters of the funnel’s spout top. Record the amount of water added.
5. Fill the test tube with water and record the amount of water.
6. Place thumb over test tube opening and turn it upside down.
7. Place test tube over funnel spout as the thumb is quickly removed. Some water may escape the test tube; however, this is not a problem unless more than two centimeters of water escapes. (may want to practice in advance)
8. Measure and record the water level in the test tube. Mark the water level with a grease pencil.
9. Record observations and take pictures.
10. Place experiment setup in sunny area or use plant lights.
11. Continue making observations for five days. Be sure to include any water added to the beaker and level of water in the test tube, along with any other data students need to support experimental findings and conclusions.
12. Prepare a presentation of data collected, findings, and conclusions. (using science class Wiki, Goggle Docs presentation, or Power Point)

Questions for Students:

1. What conclusions may be drawn from this experiment?
2. What caused the water level to decrease in the test tube?
3. Was the water completely displaced in the test tube?
4. What evidence from the findings or data caused the conclusion that oxygen is inside the test tube? (this question assumes that some students said oxygen)
5. What happened to the algae in the beaker?
6. What would happen if the experiment was placed in a dimly lighted area?
7. What would happen if the experiment was placed inside a dark cabinet?

Further questions will develop based on student responses to the questions above. Also, questions to ask students in science projects provide additional types of questions to ask.

Algae and Oxygen Demonstration

The following demonstration is designed to prove that the algae did make oxygen during this science experiment.

1. Have students predict what happens when a smoldering candle wick is placed inside a test tube.
2. Light a very thin candle, approximately 15 centimeters long, and then blow out the flame.
3. Quickly place the smoldering end of the candle inside a test tube. (nothing happens, the candle does not relight)
4. Now have students predict what happens when a smoldering candle wick is placed inside a test tube from the experiment.
5. Have one student group remove the test tube from the experimental setup, ensuring the test tube remains upside down at all times.
6. Place the smoldering candle wick inside the test tube. (the candle relights)
7. Have students explain why the candle relit in the test tube from the experiment.

Making Connections

Students develop a better understanding of the photosynthesis chemical process, along with energy transformation based on the concrete evidence provided by this experimental findings and conclusions. Students follow an inquiry-based process, along with using basic and integrated process science skills during the experiment.

The copyright of the article Making Oxygen Through Transformation of Energy in Curricula/Lesson Plans is owned by David R. Wetzel. Permission to republish Making Oxygen Through Transformation of Energy in print or online must be granted by the author in writing.

Use Algae to Make Oxygen

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