Title: Mass Lab

Problem: Will our balances or scales measure the mass of an object the same every time?

Hypothesis:

Materials:

• 1 large rock
• 1 small rock
• balance or scales
• pencil or pen, paper, and graph paper

Procedure:

2. Find the mass of the small rock. Make sure that you are as accurate as possible. If you are not sure about how to find the mass or zero your balance, ask the teacher. Record this mass in the data table.
3. Now, zero the balance again or move all of the masses to 0, remove the small rock and now find the mass of the large rock. Record this mass in the data table.
4. Repeat steps 1-3 four more times, recording your data as you go. Be sure to alternate the small rock and then the large.
5. Find the mass of the small rock 5 times in a row, zeroing your scale between each measurement. Record these measurements in the data table.
6. Now, find the mass of the large rock 5 times in a row, zeroing your scale between each measurement. Record these measurements in the data table.

Data:

 Object Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Difference small rock, alternating _______ g _______ g _______ g _______ g _______ g _______ g large rock, alternating _______ g _______ g _______ g _______ g _______ g _______ g small rock, sequential _______ g _______ g _______ g _______ g _______ g _______ g large rock, sequential _______ g _______ g _______ g _______ g _______ g _______ g

Analysis:

1. Did you get the same mass each time when you alternated the rocks?
2. What was the biggest difference you found between the masses of the small rock when you alternated it? To find this value, subtract highest reading from lowest and record it in the data table.
3. What did you notice about the mass of the small rock when you didn't alternate it?
4. What was the biggest difference for the large rock when you alternated it?
5. What did you notice about the mass of the large rock when you didn't alternate it?
6. Is the balance more precise for large or small objects? That is, were the measurements more consistent for the small rocks or the larger rocks?
7. When is your balance going to be the most precise?
8. Make a bar graph of the differences between each rock type and measurement type to illustrate when the scale is the most accurate and when it is not.
9. What does precision mean?

Conclusion: (Was your hypothesis right? What did you like about this lab? What are two things that you learned from this lab? Which method was the easiest to use? Which was the hardest?)

Teacher page for the Mass Lab