Science Buddies: "Ask an Expert"

I have to do a science project on "hot ice" for school. Well i saw that instant hot ice video and i thought well this is a pretty good idea for a grade eighth science fair project! My teacher thought it was good too but then he asked me "whats the question?" And i said hot to make hot ice but he said no to it so i need help here! What should my question and my hypothesis be? Thank You

Here are some links:
* http://www.youtube.com/watch?v=aC-KOYQsIvU
* http://chemistry.about.com/od/homeexper ... cetate.htm

My project is due 1-6-14 so please help. Thanks

Looks like fun!

I think there are several questions you could investigate with sodium acetate. One suggestion that comes to my mind is what concentration of sodium acetate produces the most heat? Sodium acetate is a common part of hand warmers and having the right concentration of sodium acetate will help warm your hands the most. You would need to control for the starting temperature of your ingredients (water, sodium acetate), how long you heat them on the stove, and the total volume of the mixture tested.

Additionally, I found this project in the Science Buddies Project Ideas section that deals with sodium acetate: https://www.sciencebuddies.org/science- ... p085.shtml

I am this project for science fair: https://www.sciencebuddies.org/science- ... p085.shtml . I have the purpose which is "how the starting temperature affects crystal growth and heat generation in a supersaturated sodium acetate solution", i just need help with the hypothesis and with the variables like independent variable, dependent variable, control group and experimental group. Please help Thank You.... !!!!

Hi,

Welcome to the forums.
Have you had a chance to check out ScienceBuddies' Project Guide page?
https://www.sciencebuddies.org/science- ... ndex.shtml

You will find information regarding independent variable(s) and dependent variable(s). Also, from that page, you will learn how to write a hypothesis.
I suggest that you read the page and try to figure them out by yourself first before looking at the "possible answers" below.






For your case, the independent variable could be the starting temperature.
The dependent variable would be something that would change in response to different values of the independent variable. Your purpose statement suggests that some measurable variables related to crystal growth or heat generation will be suitable to be the dependent variable(s). So, the size or weight of the crystal could be your dependent variable. Other measurable variable for heat generation could also be your dependent variable.

From the web-page I suggested, you will also learn what "controlled variable" is.
However, I don't think control group or experimental group applies in your project, though.
For example, if I want to test the efficacy of certain drug, I would have one group of people (the experimental group) take the drug and another group of people (the control group) take some placebo as a comparison.

JChang

I read the science fair guideline and made a hypothesis which is "If I boil and microwave the substance in its liquid state correctly then the substance would change into a solid state". Can you see if my hypothesis is correct if not can you improve it or suggest me one??? Thank You in advance...... !!!!!

Hi,

It's great that you read the hypothesis guideline. I think you are heading in the right direction.
Basically you want to say something like this: "If I do something about the independent variable, the dependent variable will response in certain way."
You also want the hypothesis to be as specific as possible.
The word "substance" in your hypothesis sounds vague. What is it exactly?

Keep your independent variable and dependent variable in mind when you write your hypothesis.

Are you going to follow the procedures in this project? https://www.sciencebuddies.org/science- ... #procedure
If so, the starting temperature could be your independent variable, and crystal size and the temperature at the end of the experiment could be your dependent variables.

Here are some examples:
"If I activate the hand warmer at a higher starting temperature, the crystal size of the sodium acetate will be larger after activation."
"If I activate the hand warmer at a higher starting temperature, the hand warmer's temperature after activation will be higher."

Hope this help!

JChang

Hi!I am doing this project called Hot Ice and I need help with the experiment. The experiment is in these websites: http://chemistry.about.com/od/homeexper ... cetate.htm OR http://www.wikihow.com/Make-Hot-Ice.....(the home experiment for that one).I tried the experiments but it didn't work. I also followed YouTube videos on How to make hot ice with baking soda and vinegar but nothing worked.The problem is that when I saw film of crystal while boil the solution of adding baking soda and vinegar, I mixed 1/3 cup of vinegar to dissolve the little crystal but some of the little crystal stays. In addition, after boiling my solution turns white but it should yellow or brownies like in the YouTube videos and the website.After that I cooled it in the refrigerator,when I took it out it turned solid instead of being liquid like the YouTube videos. Can explain what is going on and tell me what to do? I WOULD APPRECIATE ANY HELP i CAN GET....Thank you!!!

It's rather hard to guess what might be going wrong from this description. It looks as though you're supposed to pour off the liquid from the crystal-filmed-over pan (i.e. don't include most of the crystals from the pot, pour it into another container). If, after pouring off the solution, you still have a few crystals, you should only have to add a very small amount of vinegar to dissolve them. I would guess that you're probably pouring too fast, or not gently enough, or otherwise are bringing too many crystals along with your solution.

That really helped but i'm actually doing a project a little different from this. The purpose is same but the material and the procedure are in these website: http://chemistry.about.com/od/homeexper ... cetate.htm or http://www.wikihow.com/Make-Hot-Ice ...(home experiment for that one). since the purpose is how the starting temperature affects crystal growth and heat generation in a supersaturated sodium acetate solution I'll test the temperature with a thermometer in between the experiment. So I kinda changed your suggested hypothesis, can you tell me if it's correct : If I activate the solution of sodium acetate at a higher starting temperature, the crystal sculpture of the sodium acetate will be stronger after activation.

It's great to hear that my suggestions somewhat helped. And you've got the basic idea about how the hypothesis should look like!
Basically you will be measuring the effect of independent variable (activation temperature) on the dependent variable (something related to the crystal). The effect should be easily measurable. So you need to think about how you would measure "strength" since "strength" is your dependent variable according to your current wording.

"... the crystal sculpture of the sodium acetate will be stronger after activation."

If you do not have an easy way to measure strength consistently, you might want to change the wording of the hypothesis to some quantities that can be measured more easily (e.g. size?).
Also, may I suggest a more precise wording with the first part of your hypothesis since your wording of "activate the solution" is not very clear to (I am just being picky here).

If I activate the crystalization process of the supercooled sodium acetate solution at a higher starting temperature

JChang

According to what you said, I decided to kinda change my hypothesis.I put your hypothesis and my hypothesis together and wrote this: "If I activate the crystallization process of the supercooled sodium acetate solution at a higher starting temperature, then the crystal sculpture of the sodium acetate will be the crystal size of the sodium acetate will be larger after activation". The problem is that I don't understand your last part of hypothesis (the crystal size of the sodium acetate will be larger after activation). What do you mean by that? Can you explain it to me, it's just that I'm am worried what if my teacher asks me what does the hypothesis mean while presentation, i would be lost .... . I know I am predicting stuff because i am nervous and you never know she might ask me. So please help, THANK YOU.

Thank you....that really help. I have decided to do this project. The problem is with the procedure. In between the experiment, you are suppose to check the temperature with a thermometer and i did. I don't know why but when i test it, at first my thermometer states 188 fahrenheit, next it beeps and then it shows 7 fahrenheit whether i am testing it before or after cooling. I think something is wrong with my thermometer. So can you tell me what's wrong and can you suggest me any type of thermometer that is for checking the temperature of ice. Maybe i have to wait a little longer for appropriate temperature to come on the thermometer that goes with ice. Also another problem is that this is preventing me from doing the graph. So I need your help.

Hi, cutiepie8545.

We noticed you have duplicate threads going on the same topic. It helps both our mentors and other students to limit the discussion to one thread so everyone sees what has already been discussed. We have merged the two threads together.

Our mentors have provided excellent advice so far. Thanks for using Science Buddies, and good luck in with your project!

Hi cutiepie8545,

Do you still have problems with your hypothesis?
I don't understand the last part of your hypothesis either:

... then the crystal sculpture of the sodium acetate will be the crystal size of the sodium acetate will be larger after activation

If you are going to build a crystal sculpture with the supercooled solution, you need to find easily measurable quantity as your dependent variable.
If you just want to observe the crystalization process, the crystal size of the sodium acetate could be your dependent variable and the following sciencebuddies project offers some suggestion on how to measure the crystal size:
https://www.sciencebuddies.org/science- ... #procedure
This project also suggest some thermometer to use (see the Materials tab).

If you just want to measure the temperate before crystalization, I suppose the general purpose thermometer like this one below should work:
http://www.amazon.com/H-B-Instrument-Im ... m_indust_5

This youtube video offers quite some useful tips and scenarios.
https://www.youtube.com/watch?annotatio ... xk3OZWq9Ls

JChang

Sorry. That was my mistake, what i meant was that : then the crystal size of sodium actate will be larger after activtion..

Hi JChang,
Can you explain your last part of hypothesis? Also, I need help for the website: https://www.sciencebuddies.org/science- ... #procedure . I am following the purpose from this website and following the the purpose in this website : http://chemistry.about.com/od/homeexper ... cetate.htm . Since i am using the purpose from the science-buddies website i mixed the procedure up.....
1) Add 6 tablespoons of baking soda to a pot.
2) Add 2 liters of white vinegar to the baking soda until it stops fizzing.
3) Boil the solution until around 90% of the water has evaporated.
4) Move the completed solution into a smaller (preferably glass) container and add 1 or 2 tablespoons of vinegar.
5) Stir solution.
6) Cool it in the refrigerator.
7) Add a bit of crystallized sodium acetate to your aqueous solution and watch your hot ice form. Start the timer to see how long it takes for the entire hand warmer to crystallize. Record the temperature of the hand warmer every minute for 15 minutes. Observe the crystals that are formed.
OR you can construct towers of hot ice.
I know how to do graph. The problem is that i don't understand the data process, it says "Graph the Starting Temperature on the x-axis vs. the Time to Complete Crystallization on the y-axis" but the time it took is one number how am i going to put just one number meaning one data point in the graph. Thank you!!!!

Which last part of hypothesis are you referring to?

If you follow the procedures carefully, you will have starting temperatures at 0, 20, and 40 degrees Celsius.

The following procedure corresponds to the starting temperature of 0 degree Celsius.

Observing the Effect of a Cold Starting Temperature on Crystallization Growth
Add ice and water to one of the coolers, enough that it will cover a hand warmer.
...

The section "Observing the Effect of a Hot Starting Temperature on Crystallization Growth" corresponds to the starting temperature of 40 degrees Celsius.

For each starting temperature, you will have a corresponding "time to complete crystallization."
Therefore, you will have three data points to plot.

JChang

The last part that states " the crystal size of the sodium acetate will be larger after activation." What do u mean? Also when i said i need help with the data process, i meant was that i need help with the time it took to Complete Crystallization. The time it took is one number, so how am i going to put just one number meaning one data point in the graph. Is is correct to do it like that? So please help, Thank you!!!!

The hypothesis's wording depends on what specific experiment you are doing. Typically, the first part of the hypothesis states what you are going to do with your independent variable (for example, change the starting temperature), and the 2nd part of the hypothesis states how the dependent variable will respond to the changes in independent variable.

So IF you decide to use the crystal size as your dependent variable, then it makes sense to have wording like this: "the crystal size of the sodium acetate will be larger after activation." You could measure the length of the crystal to represent the crystal size as described in https://www.sciencebuddies.org/science- ... #procedure.

IF you decide to use "the time it took to Complete Crystallization" as your dependent variable, then you need to word your hypothesis correspondingly; for example "the time for the hot ice to complete crystallization will be shorter."

Regarding plotting the data points, as I mentioned in previous reply, IF you follow the procedures in the above link (or a modified version of it), you will conduct your experiment with the starting temperature at 20 degrees, then at 0 degree, and then at 40 degrees (as described in the link). For each starting temperature, you will have a data point for "time to complete crystallization". For three starting temperatures, you will have three data points, then you can plot the three data points: just plot the "time to complete crystallization" on the y-axis and "starting temperature" on the x-axis.

JChang