Calculating Steel Density from Experimental Data in Excel: Troubleshooting Tips

In summary, the conversation discusses a physics lab where the student is having trouble finding the correct density of steel using experimental data in Excel. The student shares their data and formulas, and other members suggest checking for consistency in units and using the correct formula for volume of a sphere. Eventually, the student realizes their mistake and successfully calculates the correct density.
  • #1
TalRoc
4
0
So I received a lab today for physics. The first part of the lab I finished in about 20 minutes,had no trouble with it, but I don't understand what I'm doing wrong in the second part. I have to find the density of steel in excel, using experimental data that we found in class a few weeks ago.

The diameter, mass, and volume of the sphere are correct. This is my data:
Diameter Mass Volume
3.97 0.36 8.31
6.2 1.04 12.98
9.4 3.52 19.68
12.5 8.35 26.17
13.45 10.02 28.16
15.67 16.3 32.80

But for the density I keep getting these numbers:
Density
0.043318519
0.080131498
0.178886028
0.31910828
0.35588284
0.49691284

The balls are made of steel, so obviously the density I found is incorrect. Can someone please tell me what I'm doing wrong. I know the density is mass/volume... I know that, so I don't know what I'm doing wrong.
I'm sorry that the density and stuff are messed up, I don't know why physics forum did so
 
Last edited:
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  • #2
Hi TalRoc, http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

All physical measurements in science have units associated with them, could you please indicate the units appropriate to your figures.

I can guess how you might have measured the diameter, but how did you measure the volume?

Roughly what value of density are you expecting you should get?
 
Last edited by a moderator:
  • #3
I checked a few of the numbers from your experiment. If you have measured the diameter of the sphere, there should be some correlation with the volume. If these two numbers are using consistent units, then the formula for the volume of a sphere given the radius must have changed.
 
  • #4
NascentOxygen said:
All physical measurements in science have units associated with them, could you please indicate the units appropriate to your figures.

I can guess how you might have measured the diameter, but how did you measure the volume?

Roughly what value of density are you expecting you should get?

Okay, so diameter is in cm, volume is in cubic centimeters.
Also thanks for the quick reply!
 
  • #5
SteamKing, thanks for the help, but I still don't get why excel is coming up with those numbers.

This is a screenshot of my excel document: http://gyazo.com/9aa4422a96414b614a2aa152563d50cf

Please tell me what I'm doing wrong I'm really confused :/
 
  • #6
According to the formula in the Excel spreadsheet, the volume of a sphere is (4/3)*pi*r. You might want to check that.
 
  • #7
Got it. I was making a stupid mistake the whole time and forgot to multiply by 1000 at the end...
And I was wrong the units were mm and g. I see what I did now.

Thanks guys
 

1. What equipment do I need for a physics lab?

The specific equipment needed will depend on the experiment you are conducting. However, some common equipment in a physics lab includes rulers, measuring devices, stopwatches, balances, and various types of sensors.

2. How do I set up a physics lab?

To set up a physics lab, you will need to gather all necessary equipment, read the lab instructions carefully, and follow any safety precautions. Then, assemble the equipment according to the instructions and ensure that all measurements are accurate before beginning the experiment.

3. What safety precautions should I take in a physics lab?

It is important to always wear appropriate personal protective equipment, such as goggles and lab coats, in a physics lab. You should also follow all safety instructions provided in the lab manual and never conduct experiments without supervision.

4. How do I record and analyze data in a physics lab?

In a physics lab, data is typically recorded using a data table or graph. Make sure to label all axes and units correctly. To analyze the data, you may need to use mathematical equations or statistical methods, depending on the experiment.

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