How to Make Photosynthesis Demonstrations

Photosynthesis is the process where plants combine carbon dioxide and water vapor to create sugar, water and oxygen. This biological reaction cannot take place without the presence of sunlight. To prove that oxygen is actually created during photosynthesis, Elodea (an aquatic plant), will be exposed to sunlight. Any gas that is given off will be channeled by an overturned funnel into an empty test tube that is marked with milliliters. After photosynthesis has been allowed to occur, the amount of gas in the top of the test tube will be measured and recorded.

• 1

  Add several teaspoons of sodium bicarbonate to a mason jar full of warm water.

• 2

  Pour some of the sodium bicarbnate into the test tube until it is full.

• 3

  Add several pieces of Elodea, which is an aquatic plant, to the test tube.

• 4

  Put your thumb over the top of the test tube and turn the tube upside down.

• 5

  Insert the test tube into the mason jar, being careful not to spill any contents.

• 6

  Place the lamp next to the test tube and turn it on. Allow the lamp to shine on the test tube for 24 hours.

• 7

  Observe the level of the gas in the top of the test tube after 24 hours.

• 8

  Observe the level again after 48 hours. The gas should increase at a steady rate.

• 9

  Pull the test tube out of the mason jar and let the contents fall out of the test tube into the water. Keep the test tube in the inverted position.

• 10

  Light a kitchen match, blow it out and then insert it into the test tube. The match ought to start to burning again, if oxygen is present. The presence of oxygen is a sign of photosynthesis.