Science Buddies: "Ask an Expert"

Hey
I Have an Extended Experimental Investigation.
I have to create a Researchable hypothesis to invistigate the physical and/or chemical porperties of either metallic or crystalline material.
Design a experiment to test my hypothesis
Do the experiment
Observe, collect, record, interpret and evalute data form my investigation
Present my findings as a scientific report.

Ok so i choose to investigate "why do alloys have different physical and chemical properies to its parenting metals?"

I am still in the process in writing a decent hypothesis

The experiment i used was Melting 10g Tin then mold it in to pellet for. I did the same for 10g Lead. The same for 5g lead 5g tin. I did a scratch test on the metals after they had been melted. I droped them form a 3.6m ledge onto a hard surface. Then i put the 3 metals on a hot plate till on of them started to metal. The one that melted first was Tin+Lead(Solder).

So know i am asking why did i get these results. Who come Solder melts at a different temperature to its parent metals Tin and Lead.

I am also having trouble creating a hypothesis i have read these 2 links
https://www.sciencebuddies.org/mentorin ... bles.shtml
https://www.sciencebuddies.org/mentorin ... YQodeicBLA

but i still dont understand what to write.

Please reply quick have to hand in a rough draft tommorow.
Thanks

newme wrote:Hey
I Have an Extended Experimental Investigation.
I have to create a Researchable hypothesis to invistigate the physical and/or chemical porperties of either metallic or crystalline material.
Design a experiment to test my hypothesis
Do the experiment
Observe, collect, record, interpret and evalute data form my investigation
Present my findings as a scientific report.

Ok so i choose to investigate "why do alloys have different physical and chemical properies to its parenting metals?"

I am still in the process in writing a decent hypothesis

The experiment i used was Melting 10g Tin then mold it in to pellet for. I did the same for 10g Lead. The same for 5g lead 5g tin. I did a scratch test on the metals after they had been melted. I droped them form a 3.6m ledge onto a hard surface. Then i put the 3 metals on a hot plate till on of them started to metal. The one that melted first was Tin+Lead(Solder).

So know i am asking why did i get these results. Who come Solder melts at a different temperature to its parent metals Tin and Lead.

I am also having trouble creating a hypothesis i have read these 2 links
https://www.sciencebuddies.org/mentorin ... bles.shtml
https://www.sciencebuddies.org/mentorin ... YQodeicBLA

but i still dont understand what to write.

Please reply quick have to hand in a rough draft tommorow.
Thanks

Well, you should usually create your hypothesis before you do your experiment. A hypothesis state what you think will happen in your experiment- "the hypothesis must be worded so that it can be tested in your experiment. Do this by expressing the hypothesis using your independent variable (the variable you change during your experiment) and your dependent variable (the variable you observe-changes in the dependent variable depend on changes in the independent variable). In fact, many hypotheses are stated exactly like this: "If a particular independent variable is changed, then there is also a change in a certain dependent variable.""

So, why did you test what you tested, and what did you think will happen?

Note- in a lot of science fairs (and science) creating your hypothesis _after_ you did the experiment is considered to be a very bad thing. It means you didn't plan your research well, may not have had the appropriate experimental methods and controls (since you did not know what you were testing).

Why you got the results you did isn't the same as your hypothesis. Your hypothesis could be right or wrong. Explaining your results is based on your research (both experimental and reading/library work). I suggest you review the project guide again, since you seem a little unclear on these points.

Don't expect quick response on these forums. They are checked at least once a day by an expert, but we are in different time zones and different schedules.

Oh, one last thing. Alloys generally don't melt at a single temperature (unless they are a very special ratio- called a eutectic mixture. 50/50 is not a eutectic mixture for lead and tin. It also has a pretty high melting point compared to the ratio commonly used for solder). "Starting to melt" isn't usually considered a good metric for materials characterization. Either the range of melting is reported (such as 190-203 degrees Celsius) or the specific melting point (like 197 degrees celsius) is reported.

Louise

sorry about the double post i clicked new post and didnt realize till i read the forums

Thank you for the quick response.
You have given me a much better understanding of what to do.
See because i have moved from a country that dosnt have assigments in their schooling system to Australia which is a country that uses a lot of assignment. So since this is my first chemistry assigment i am very confused on how to start and were i should start. so know i have a better understanding on how to start. So i shall write a hypothesis then find a experiment that will fit with it. Do the experiement and see if it goes with my hypothesis.
Thank you again

newme wrote:sorry about the double post i clicked new post and didnt realize till i read the forums

Thank you for the quick response.
You have given me a much better understanding of what to do.
See because i have moved from a country that dosnt have assigments in their schooling system to Australia which is a country that uses a lot of assignment. So since this is my first chemistry assigment i am very confused on how to start and were i should start. so know i have a better understanding on how to start. So i shall write a hypothesis then find a experiment that will fit with it. Do the experiement and see if it goes with my hypothesis.
Thank you again

Yes, this is correct. For example, a hypothesis is "The melting range (or the midpoint of the range] of a mixture of solder will be lower as the percentage of tin increases". [ Then, you could test 0, 10, ...,90, 100 tin/lead mixtures, measure the melting point or melting range and see if your hypothesis is correct.]

Louise