What is the control in a photosynthesis experiment?

What is the control in a photosynthesis experiment?

Variables. Independent variable – the light intensity (how close the light is). Dependant variable – the number of oxygen bubbles given off (the rate of photosynthesis). Controlled variables – the size of the pondweed, the volume of water used and its temperature.

What happens when you use a straw to blow into a beaker that has water and BTB?

Blowing into the straw causes carbon dioxide to dissolve in the water, forming a solution of carbonic acid. The bromothymol blue indicator should turn from blue to green to yellow as the solution becomes more acidifc.

What are some additional variables we could test in this photosynthesis experiment?

1) the variables of light intensity, temperature, carbon dioxide, light quality all influence the rate of photosynthesis. 4) food production for animals and humans on earth is dependent on plants. By increasing the use of carbon dioxide by plants, it may help slow global climate change.

When you blew air in the test tube through straw what caused the solution with bromothymol blue to change color?

What caused the bromothymol blue solution to change color? The bromothymol blue solution changed color because there was a chemical reaction with the carbon dioxide. 3.

What happens if you blow BTB?

The BTB will turn yellow after you’ve blown into it, this change occurs because the carbon dioxide in your breath is acidic and BTB is an indicator. It may appear more yellow/green then blue. Create a “stock” to use with the class by adding a weak base (NaOH) to get the color to a blue.

What is the purpose of blowing air in the pH indicator?

Figure 12: Blowing air into the liquid introduces carbon dioxide, which slowly changes the pH value. Step 4: Compare the final colour with the pH table of the indicator and determine the pH value. Figure 13: After blowing for several minutes, the colour stops changing.