Activity #1

ACTIVITY #1

Questions to answer accompanying experiment:

1. Does hot water or cold water freeze faster?
Hypothesis: I predict that the cold water will take less time to freeze because it is closer to a freezing temperature than the hot water. Hot water will use more energy to first become colder and then be capable of freezing.
2. Does hot water or cold water boil faster?
Hypothesis: I predict that the hot water is able to boil faster than the cold water because the original temperature will be closer to that needed for water to boil. The cold water will have to heat up before it will be capable of reaching boiling.

3. Does salt water freeze faster or slower than regular water?
Hypothesis: My prediction is that the salt added to the water will allow it to retain some heat, making the process of freezing take longer than that of water without salt added.


#1- Which freezes fastest? Hot or cold water?

This image shows the containers used to perform the Hot versus Cold freezing water experiment














Controlled Variables for Hot versus Cold freezing experiment:

• Amount of water per container (1 cup)
• Length of time exposed to freezer temperature (30 minute intervals x 2)
• Placement in the freezer (placed side by side to allow both containers to have equal exposure to freezing cold blast of air)

Theory:

Cold water freezes faster than hot water because the original temperature allows less energy to be used.

Conclusion:
After repeating this experiment three times, I have concluded that the cold water IS able to freeze more quickly than the hot water. Thus, justifying my original hypothesis that the original temperature must be closer to freezing. 

And the winner is...

COLD water!

THUS, hot water loses for lack of energy efficiency reaching the freezing temperature

Hot water #1	Cold water #1	Hot water #2	Cold water #2	Hot water #3	Cold water #3
~60 minutes	~35 minutes	~55 minutes	~30 minutes	~60 minutes	~35 minutes
	Frozen faster		Frozen faster		Frozen faster

#2 Which boils fastest? Hot or Cold water?

This image shows the exact setup for each of the 3 trials in the Hot versus Cold boiling water experiment















This is an image of the Hot water beginning a rolling boil

This is an image of the Cold water prior to reaching a boiling temperature ( Photo taken immediately after the prior image)

Controlled Variables for the Hot versus Cold water boiling experiment:

• Amount of water used in this experiment (2 cups per pan)
• Size of pan and stove burners (equal volume per pan and circumference per burner)
• Heating temperature per burner (labeled as "8" on the stove top)

Theory:

Cold water will require more energy to boiling because it must first heat up before becoming capable of reaching the boiling point.

Conclusion: 

I repeated the hot versus cold boiling water experiment three times, and was able to conclude that my initial hypothesis was accurate. Hot water is closer to the temperature needed to boil water, whereas cold water must first become hot before reaching the boiling point.

Hot water #1	Cold water #1	Hot water #2	Cold water #2	Hot water #3	Cold water #3
4 minutes 33 seconds	8 minutes 10 seconds	3 minutes 25 seconds	7 minutes 24 seconds	4 minutes 29 seconds	9 minutes 2 seconds
Boiled faster		Boiled faster		Boiled faster

#3 Which freezes faster Salted or Unsalted water?

This is an image of the identical containers used to conduct the Salted versus Unsalted water freezing experiment

This is an image of the placement of both containers in the freezer

Controlled variables for the Salted versus Unsalted freezing water experiment:

• Amount of water per container (1 cup)
• Length of time exposed to freezer temperature (30 minute intervals x 3)
• Placement of the containers in the freezer (placed side by side in the freezer for equal exposure to freezing cold blast of air)
• Temperature of water for both containers (room temperature/ neither hot or cold)
• Amount of salt added to the container (1 Tablespoon)

Theory: 
The unsalted water will be capable of freezing faster due to the lack of salt. My understanding is that the salt added to the water will prohibit it from cooling as quickly as the unsalted comparison.

Conclusion:
The unsalted water IS able to freeze more quickly than the salted water.



This is an image of the salted water after the third 30-minute interval. The surface is slightly frozen, but the water beneath is still cool liquid.

This image shows the unsalted water after the third 30-minute interval. The  entire amount of water has frozen to a solid state.

Salted water #1	Unsalted water #1	Salted water #2	Unsalted water #2	Salted water #3	Unsalted water #3
~85 minutes	~60 minutes	~90 minutes	~65 minutes	~80 minutes	~55 minutes
	Frozen faster		Frozen faster		Frozen faster

Images of the atoms that make up water molecules

 

The following link explains the arrangement of the three states of matter for water:

Scientific method:

 Based on previous observations, I predicted that colder water would reach the freezing point more quickly. I hypothesized that the cold water for my first experiment would freeze faster than the hot water, despite the controlled variables in the test. I tested my hypothesis three times for the hot versus cold freezing experiment, and was able to determine that my prediction was correct. For the second experiment, I believed that hot water would have the potential to boil faster because it is closer to the boiling temperature. After testing my theory three times, I was able to determine that my prediction was accurate. Due to the higher temperature the hot water is able to reach its boiling point, while the cold water is still heating up. For the third experiment, I used my knowledge of the ocean to based my theory about salted versus unsalted water. My reasoning was that if salt is added, then the water will retain some heat-therefore taking longer to freeze from room temperature. I conducted the experiment three times to ensure that my data was correct. I discovered that the salt did slow the freezing process significantly, and that in fact the unsalted water froze quickly in comparison.

Repeat-ability:
Each of these three experiments concluded accordingly to my initial predictions. I believe that by increasing the amount of trials for each experiment I was able to make a comprehensive decision about the accuracy of my prior knowledge. Repeating each experiment three times helped to solidify the validity of the claims that I had made in each hypothesis.

The experiments conducted in Activity #1 help to build the scientific concepts related to solids, liquids, and gases. The freezing and boiling points for water are impacted by the original temperature used. Additionally, adding salt to water does slow the freezing process significantly. The addition of other molecular compounds into the water can effect the duration of time necessary to freeze the water.

The three experiments I conducted are necessary for real world application because they each include common items. The next time that I am making ice cubes, or wish to boil water quickly, I will be able to apply the knowledge I gained from preparing these three experiments. Also, using salt to slow the freezing process could be helpful for storing some foods and preventing "freezer burn." In my opinion, the experiments that I conducted have real-life value for everyone who spends time in the kitchen preparing items like ice cubes or boiling water.

 The experiments that I conducted for Activity #1 will become even more useful for me as an Early Childhood educator because I now have a better understanding of the three states of matter for water. Since I tested each experiment three times, I feel that I am ready to implement this experiment in the classroom. I will be more informed in relaying the significant scientific details that accompany such experimentation. I believe that children would find this experiment exciting, very informative, and yet simple to conduct.