# Physics 8-13-13 Measuring in Physics, continued…

PHYSICS: Did you remember sig figs? All this SI and calculations stuff will come back to you before you know it. Holler if we need to practice at a help session.

When you multiply or divide, the number in the problem with the fewest sig figs determines the number of sig figs in the answer. When you add/subtract, the number in the problem with the lowest decimal value determines the place of the last sig fig in the answer. And remember, you never go by counting numbers or conversion factors.Don’t forget to show all your work!

Now, let’s see you put it all together in the lab tomorrow! 🙂

UPDATE – The textbooks website was down last time I checked, so I’ll move the homework to Thursday.

flickr photo by jambe

## 28 thoughts on “Physics 8-13-13 Measuring in Physics, continued…”

1. Hudson C P5 says:

Is the homework assigned for tonight on the syllabus still due tomorrow or is it pushed back?

• Ms. Skinner says:

Hudson- Still due tomorrow since we didn’t do anything new today.

2. Nicolas K P5 says:

On simple problems that are simply to prove our understanding of Sig Figs, do we need to show all of the work, or do we still need to write out everything?

Ex. Number 20 on page 28

• Ms. Skinner says:

Nicolas – Not on those that are just calculator problems.

3. Carly M P5 says:

For the first lab that we did, when did you say we should have it written up?

• Josi L says:

I believe all the labs are due at the same point in time.

4. John H P5 says:

I’m assuming that our written lab reports need to be modeled after the digital manuscript form on the website?

• Ms. Skinner says:

John – Yes!

5. Bekah H P5 says:

Do we need to have the density lab written up by tomorrow? If yes, i dont have my lab book so can i write it on a piece of paper and transfer my work later?

• Ms. Skinner says:

Bekah – Not in your lab book. Y’all just need to have a plan for what you are going to do.

6. Josi L P5 says:

Do we need to collectively discuss our plan BEFORE class tomorrow?

• Ms. Skinner says:

Josi – I’m thinking it would be a very good idea to have a plan/procedure before you come to class.

7. Ryan P P5 says:

Do we know yet who the volunteers are? I know Hudson is one but who’s the other one?

• Ms. Skinner says:

Ryan – Hudson and Carly!

• Candice W P5 says:

I think Katherine is going to try it.

8. Carly M P5 says:

So, lets try and come up with a general plan! I think ms. Skinner has dropped several hints (;
Anyways, any ideas?

• Michael W P5 says:

We just have to find the density before and after the person gets in and subtract.

• evandixon says:

…by measuring the volume of water in the can before and after.

• evandixon says:

We need to measure the volume of water in the can before and after the test subject enters the can, then try calculate the density of the test subject to see if the test subject will float.

9. Will N P5 says:

Upon reflection, I’m actually pretty happy that we reviewed sigfigs…I’m a little rusty on the rounding rules. yeah

10. Hudson C P5 says:

So what is the objective for tomorrow? apparently i missed that because I can’t really think of a procedure when I don’t know the objective?

• evandixon says:

Find out whether the test subjects can float by calculating human density.

11. Nicolas K P5 says:

Hey everybody,
I don’t know if I missed something, but I need the data for the Human Density Lab. I have a picture of the data that Evan collected (Link Below), but I don’t think that we ever decided on the mass of Carly and Hudson. I can do conversions later and post them below unless that is someone else’s job.

Photo: http://goo.gl/GpHy8R

Thanks!

• Evan D P5 says:

Someone told me that we had the mass of Hudson. I don’t know what it was though.

But we can’t finish the lab report without this. (I don’t know how accurate it will be now that we waited a week.)

• Nicolas K P5 says:

Hudson’s Mass: 53.5 kg
Carly’s Mass: 67.0 kg

• Evan D P5 says:

It should be noted that I technically should have estimated one more significant figure.

• Hudson C P5 says:

Also, when you are explaining possible errors in the process, note that my mass fluctuates daily. Since we measured it today, it may have been different the day of.

12. Evan D P5 says:

Do you want the density in a particular unit? I mean g/cm^3 vs kg/m^3.