Cracker Lambust Experiment : Cracker Combustion Experiment

Because of this, many possible sources of error in the experiment have to do with water temperature changing. One possible source of error was that the water surrounding the Daphnia magna was constantly returning to room temperature. Once the 30° C water was taken off the hot plate and put in the dish, it was always cooling down to reach room temperature, 21° C, by losing heat to the air. So that the heart rate found during the three different trials may have been at varying temperatures, some cooler than 30° C. Once the 10° C water was put in the dish, it was always warming up to reach room temperature, by gaining heat from the air. This may have caused the heart rate that was found during the three different trials to have been at varying temperatures, some warmer than 10°

The main objective of this experiment is to differentiate between a physical change and a chemical change.

1. For this experiment, what were the independent variable and the dependent variable? What were the constants?

The independent variable for the experiment was the paper towels. The dependent variable was the absorbency and strength. The constants for the experiment were the size of the paper towels that were used, the amount of water, the size of the beaker, the size of the cylinder and the amount of the weight.

I took the graduated cylinder and started filling it up with water until the bottom of the meniscus was to the the 100.0 mL mark with the assistance of a dropper pipet. I then took the 13 x 100 mm test tube and slowly poured the water from the graduated cylinder into the test tube until it was full to the top. I then poured the water in the test tube out into the sink and put the graduated cylinder on the counter so I can get an accurate measurement of the lower meniscus to record on my data table. I once again followed the same procedure again filling a second test tube with water from the graduated cylinder then setting it on a straight surface to get an accurate measure of the volume to

* By using the dropper and measuring cylinder, an amount of 5ml milk was placed in the test tube

14. The experiment was repeated with each water temperature until all tests had been conclusively completed.

The reaction time (in seconds) is the dependent variable of this experiment. This will be changed by the temperature of the chemicals, and as it is affected by the independent variable it is considered the dependent variable.

A. Water boils at 100°C at sea level. If the water in this experiment did not boil at 100°C, what

The volume of a small test tube and a thin-stemmed pipet were determined in this section of the lab. Water was poured into a small test tube until the water reached the very top edge of the test tube. The test tube was then emptied into a plastic 25 mL graduated cylinder and volume was measured and recorded into data table 3. A think-stemmed pipet was completely filled with water. Drops were carefully counted and emptied into the empty plastic 25 mL graduated cylinder until the water level reached 1 mL. The number of drops in 1 mL was recorded into data table 3. The thin-stemmed pipet had a total volume of 4 mL and that was also recorded into data table 3.

The amount of tablets did effect the temperature of the water. Our findings made our hypothesis incorrect. The temperature of the water did increase as the number of the tablets increased also. In this experiment, the finding were quite surprising, simply because I thought that the temperature of the water will decrease as the amount of the number of tablets increased. In the real world I feel like this information would be beneficial, because it shows the reaction of an acid plus a base mixed with water.

In this experiment, we investigate the change in temperature caused by adding a chemical substance into the water and dissolving it. The results recorded in the table below show that our hypothesis is correct.

In this experiment, I will be investigating if the change in water temperature (independent variable) would affect the time it takes for sugar to dissolve (dependent variable).

The purpose of this experiment is to determine whether or not the material that a flood is going through effects the rate and the size of the damage left behind. The independent variable in this experiment is the material that the water is going through, where as the dependent variable is the rate it takes for the water to flood through. Some controlled variables in the experiment are the amount of water used to simulate the flooding, the amount of material the water is going through, and the temperature of the water. If the water goes through rocks/gravel, then it will be quicker with less damage because there is more space for the water to go through without dragging anything out.

b) An empty beaker was weighted. Then, water was filled in the beaker. The temperature was recorded at uniform intervals.