Activity 1 - Experimental Design and Conclusions

Reflect on the expansion of water and salt water experiments you and your classmates performed. What are some of the interesting results and struggles with this experiment.

I did my experiment using an ice cube tray. I then filled one side with only water and the other side with different amounts of salt mixed in with the water. The ice cube tray slots were each about 1 inch. The slots that only had water in them expanded out of the slots and up over the edges about 2 cm. The water that had the salt mixed in with it hardly came over the edges at all in a way that was difficult to measure. The pure water expanded much more than the water mixed with salt. This is because salt causes freezing to take longer because it continues to melt the ice. The salt water lowers the freezing point therefore taking longer to freeze over than just pure water. I found it very interesting that the research that I came up with said that pure water expands about 9% when it is frozen. It was very interesting to see the expansion before my eyes. I checked on the water and salt water mixture every 25 minuets until it was frozen. This was I could observe the exact changes that were occurring right before my eyes. The salt water mixture not only took longer to freeze, but it also was not expanding much at all. The salt water was so slushy that it made things hard to measure. This is when things get difficult. The struggle with this experiment is that it is hard to measure expansion. However this was a very interesting experiment to conduct.

Relate your thoughts on this experiment to the scientific question "Is the earth warming?"

Global Warming is a controversial topic and has been for many years. This relates to our experiment because it is something that is difficult to measure and then draw up a solid conclusion. From my research I have found that the earth has been continuing to warm and then cool down for over 20 years. The observations that are being done about the earth's temperature have been taken over years. The issue with measuring the temperatures over time of planet Earth is that there is not control to compare anything to. It is very difficult to check the CO2 of the earth because there is nothing to compare it to.