Science Fair Media Presentation
By Cesar Alves
A. acids release hydrogen ion into water solution, bases release hydroxide ions into water solutions, water can make acids and bases neutral, 0-6.5 is acidic while 7.5-14 is basic. Water is neutral at 7 pH. Bases taste bitter and acids taste sour.
B. To see if the time it takes to freeze water can be manipulated by adding different substances.
C. If you put acids or bases with water then it will change the freezing rate of the water because it changes the Ph of the water
D. Parts of the experiment
1. dependent variable- the time it took for the water to freeze.
2. Independent variable- the different acids and bases.
3. control group- Basic water with nothing inserted.
4. experimental groups- Lemon juice, hydrochloric acid, milk, vinegar, ammonia, body soap, detergent.
5. Factors held constant- The amount of water in the experimental groups, 5ml; the amount of the certain substance, 5ml.
· 9 test beakers
· Safety goggles
· Safety gloves
· Lab coat
· Lemon juice
· Hydrochloric acid
· Body soap
· Baking soda
1. Put 10 Ml of water into a beaker and then put it in the cooler, 0 degree, and see how long it takes to reach a solid state.
2. Put 5 ml of lemon juice and 5 ml of water, and repeat the solid state test.
3. Do the same for vinegar
4. Do the same for hydrochloric acid
5. Do the same for milk
6. Do the same for detergent
7. Do the same for body soap
8. Do the same for ammonia
9. Do the same for baking soda
10. With all the recorded data, see if there is a difference to the just water sample.
Observations and data
A. Observation- Hydrochloric acid doesn’t freeze at 0 degree Fahrenheit, and will stay a liquid. Baking soda and lemon juice were the two shortest. Lemon juice was the fastest and didn’t take long to freeze. Water by itself took a long while to freeze than expected. Most of the substances froze around 30-40 min.
Claim, Evidence, Reasoning
I. The claim was that If you put acids or bases with water then it will change the freezing rate of the water because it changes the Ph of the water. And the evidence that supports is clearly shown when compared to the control group of just water; the substances did exactly what the hypothesis states, it changed the freezing rate. Most made it shorter than others expect hydrochloric acid which didn’t freeze at all. The reasoning is that since the other materials have different freezing points, it changes the freezing point of water if added; things like hydrochloric acid is one of the things that don’t freeze at 0 degree Fahrenheit will make it so the water doesn’t freeze.
The hypothesis and claim that If you put acids or bases with water then it will change the freezing rate of the water because it changes the Ph of the water was supported and purpose achieved. It changed the freezing rate and the ph.
Sources of error and inaccuracies
Some parts that could’ve given mistakes, like adding the wrong amount of the substance. Or if I didn’t check it often, it could’ve frozen earlier than what was written. The timers could have stopped working or broken given me the wrong time.
This is important because if someone wants something to freeze quickly or not freeze at all, that person could add some substances to long or shorten the freezing time. It is important because if you can change the freezing rate if water, it can help make something not freeze, examples including laboratory function and testing, and stuff like hydrochloric acid and gasoline which doesn’t freeze can be used to keep certain things liquid.
Some improvements would be adding different bases and acids to see if the different ph’s affect the water. And other improvement could include making the temperature lower to see if there is a difference in the substances affect on the water. And one more is making the beaker bigger to see if more of the substance changes the outcome.
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Bell, Ronald Percy. \"Acid-base Reaction (chemistry).\" Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web. 14 Oct. 2014.