Name: Diane Guo

Partners: Ana Cristina, Lawrence

Date of experiment: 2010-9-27

Factor that affect the cooling rate of water

Aim: We want to find out the factors that the affect the cooling rate of water.

Hypothesis: If we put more water, it will cool down slower.

Variables:

Input variable: Amount of waterOutput variable: Temperature of timeControl variables:

Control variable 1: Starting temperatureControl variable 2: Same container Control variable 3: 100ml measuring cylinderControl variable 4: The same thermometer

Materials:

500ml beaker Thermometer Gauze mat Tripod Bunsen Burner Water Stop watch Heatproof mat Retort stand Clamp Boss head Lighter Measuring cylinder

Diagram:

Method:

1. Set up equipment as shown in Diagram 12. Fill beaker with 200ml of water3. Light the Bunsen burner4. Wait for water to boil5. Measure the temperature each minute for 5 minutes 6. Add 100mL of water for a total of 300mL7. Heat the water to 100℃8. Measure the temperature each minute for 5 minutes9. Add 100mL of water for a total of 400mL10. Boil the water11. Measure the temperature each minute for 5 minutes12. Turn off the Bunsen burner.

Results:

Conclusion:

Our hypothesis was correct, because for the first minute, the cooling rate was 4℃/min; for second minute, the cooling rate was 3.2℃/ min; and for third minute, the cooling rate was 2.6℃/min. It was because there will be more heat if there are more water. Also in the same time, more heat will be cool down, so it will be slower than less water. Yes I do trust my data, because I can see from that table, each time the temperature cools slower than the one before it, and it is because we add 100mL more each time. So I’m sure that our data is correct. And every time we looked at the degrees on the thermometer very carefully.

Evaluation:

I think the errors in our experiment was that sometimes me and my group members forgot to wear safety goggles when lighting the Bunsen burner, also during the experiment. We are supposed to wear them during the whole experiment. And sometimes we didn't pay a lot of tensions on the experiment, and we might miss the temperature of

that time, then our data will be wrong. Next time I need to concentrate on our experiment, not talking with other people. And wear the safety equipments all the time. I don’t know why we didn’t wear lab coat this time, but last year we wore lab coat for every experiment. I think this experiment could be better by making the experiment in to a competition, see which group can cools the water first. That might be more fun to do.