History[ edit ] The phenomenon was first investigated and described by Luke Howard in the s, although he was not the one to name the phenomenon.
There is a slight risk of infection from pond water, so take sensible hygiene precautions, cover cuts and wash hands thoroughly after the work is complete. However it is probably a good idea to replace it every so often with a fresh supply from an aquarist centre or a pond.
On the day of the experiment, cut 10 cm lengths of Elodea, put a paper-clip on one end to weigh them down and place in a boiling tube of water in a boiling tube rack, near a high intensity lamp, such as a halogen lamp or a fluorescent striplight.
Check the Elodea to see if it is bubbling. Sometimes cutting 2—3 mm off the end of the Elodea will induce bubbling from the cut end or change the size of the bubbles being produced.
It does, though tend to break apart very easily, and fish may eat it very quickly. Ethical issues Look out for small aquatic invertebrates attached to the pond weed used, and remove them to a pond or aquarium. Procedure a Set up the apparatus as shown in a darkened room. Repeat twice and calculate a mean bubble count — number of bubbles per minute.
This is the mean rate of bubble production. Refer to teaching notes. Repeat the count and calculate the mean rate of bubble production as before.
Teaching notes An assumption being made in this experiment is that the gas bubbles being counted are only oxygen, and that production of oxygen is proportional to the rate of photosynthesis.
Another assumption is that all the bubbles are the same size. A variable that is hard to control is the effect of temperature as the lights used may heat the water. LED lamps produce less heat. You can develop more accurate measures by collecting the gas produced and measuring the volume of gas produced each minute or over longer time periods.
One method of doing this is to cut the graduated portion from the tube of a plastic teat pipette, fill the tube with water, plug the smaller hole with plasticine or blu-tack and invert the tube over the bubbling stem.
The students can be allocated to investigate a particular factor that affects the rate of photosynthesis, or they can choose from this list, or they can develop their own ideas.
Light intensity or distance of the Elodea from the lamp. Temperature of the water Carbon dioxide concentration. The available mass of carbon dioxide increases with each addition. Coloured filters can be used, but these will affect light intensity by different amounts depending on the colour.
Students should collect and set up all the other apparatus before collecting the boiling tube of pond weed. Check the weed to see if it is bubbling. Sometimes cutting 2—3 mm off the end of the weed will induce bubbling from the cut end, or change the size of the bubbles being produced.
The students could develop this practical as an assessed investigation if they develop hypotheses and plan the experimental detail from the core protocol. Health and safety checked, September Downloads.A variable that is hard to control is the effect of temperature as the lights used may heat the water.
LED lamps produce less heat. You can develop more accurate measures by collecting the gas produced and measuring the volume of gas produced each minute (or over longer time periods). The average temperature registered in the incubator for the experimental group was °C, and the average air humidity was percent.
After 30 days, none of the tubes with the cylinders showed microbial growth. science investigates cause-and-effect relationships by seeking the mechanisms that underlie them. The next concept—scale, proportion, and quantity—concerns the sizes of things and the mathematical relationships among disparate elements.
The Effect of Temperature on the Rate of Reaction Essay - The Effect of Temperature on the Rate of Reaction Plan: We must produce a piece of coursework investigating the rates of reaction, and the effect different changes have on them.
Measure the effects of changes in temperature, pH, and enzyme concentration on reaction rates of an enzyme catalyzed reaction in a controlled experiment. Explain how environmental factors affect the rate of enzyme-catalyzed reactions.
An urban heat island (UHI) is an urban area or metropolitan area that is significantly warmer than its surrounding rural areas due to human activities. The temperature difference usually is larger at night than during the day, and is most apparent when winds are weak.
UHI is most noticeable during the summer and grupobittia.com main cause of the urban heat island effect is from the modification of.