Middle School Science Lessons

Objectives: How can we use a triple beam balance to find the mass of these bottles of stuff?

Materials

• Single Serving Size (1L or less) bottles filled with various items
  • students brought in materials of their choice over the course of a week
• Triple Beam Balance (TBB)
• Mass Set
• Student Handout (Triple Beam Balance Bottles pdf)

Procedures – Part 1

1. Provide each lab group with an assortment of bottles
2. Students will arrange the bottles from lightest to heaviest by making observations
3. They will record the order of the bottles and their contents with #1 as the lightest and #10 the heaviest on their handout
   • my groups used 9 bottles, but there is room on the handout for 10
4. Using the set of masses, they will estimate the mass of each bottle by holding a bottle in one hand and a mass in the other hand, recording their estimations on the handout

Procedures – Part 2

1. Students will transfer their estimation to the back page
2. Using the TBB they will record the actual masses of the bottles
3. Then they will rank the bottles from lightest (#1) to heaviest (#10) and compare their estimation to the actual masses. How close were the estimations to the actual masses? Did they place the bottles in the correct order?

Results for the bottles in our class:

Bottle #	Mass (g)	Bottle #	Mass (g)	Bottle #	Mass (g)
1	126.9	14	281	27	192.3
2	72.9	15	336.5	28	330.9
3	29.6	16	223	29	465
4	438	17	70	30	195
5	202.1	18	36.43	31	59.1
6	166	19	185	32	168.8
7	63.1	20	88	33	33
8	301.5	21	140.1	34	100
9	224	22	49.1	35	402.5
10	610+	23	73.3	36	187.1
11	67.1	24	54.9	37	318.4
12	251.8	25	27.5	38
13	410.1	26	406	39

You can also use these bottles as part of your density unit, see my blog entry for more information.