Density – Identification Challenge

image

Materials:

  • Flinn Scientfic Block set (link) & Resources/Handout (pdf)
  • Ruler
  • Calculator
  • Triple Beam Balance
  • Worksheet to collect data (pdf)

For this activity, I used the set of density blocks from Flinn Scientific. Each group of students had 6 blocks made of the same material. Their challenge was to identify the material using their measurement skills to calculate the mass, volume, and density of each block. This activity also reinforced the concept that the density of an object is constant.

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Triple Beam Balance – Bottles of Stuff!

bottle_mass_5

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)

bottle_mass_4

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

bottle_mass_2

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

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.

Density Bottles Demo

Density Bottles
Density Bottles: Sand, Air, Rice, Water, & Cotton Balls in 500 mL bottles

How to use density bottles:

Demo & Discussion – For this part of the lesson, students will not handle the bottles, they will answer discussion questions based on their observations only.

  1. Share observations about the bottles.
  2. What do the bottles have in common?
  3. What is different about the bottles?
  4. What do you think the original contents of the bottle were?
  5. What phases of matter are shown?
  6. Are any of these bottles empty? Explain.
  7. Do all of these bottles have air in them?
  8. Which bottle has more air in it: Cotton Balls or Water? Explain.
  9. Which bottle is filled the most? Least?
  10. Which bottle has has the most ‘stuff’ in it? Least?
  11. Which bottle is the heaviest? Lightest?
  12. How would you order these bottles from lightest to heaviest?
  13. Estimate the mass of each bottle in grams.
  14. Which bottle is the densest?
  15. How would you arrange these bottles from least to most dense?
  16. Which of these bottles can have more of the same ‘stuff’ added to the inside of the bottle? Explain.
  17. Which bottle(s) would float in a tank of water? (I do this at the very end of the lesson with everyone at the sink)

Hands On Exploration

  1. Each group will have one set of bottles or take turns using the demo bottles and sharing their findings.
  2. Using a triple beam balance, the volume of the bottles, and a tank of water, answer as many of the questions above as you can. (for our calculations, we use the volume of the bottle’s original content (500 mL of sport drink) to give us an approximate density, not the actual density – for comparison purposes only)
  3. How did your findings compare to your observations and predictions?
  4. Dunk tank – time to find out which one will float!

Further Exploration

Give each group of students a new set of bottles (ones that they have brought in from home) and have them make observations, predictions, and density calculations.

Additional Bottle Ideas:

  • Rocks/pebbles
  • laundry detergent – liquid or powder
  • paper clips
  • paper shreds
  • crayons
  • marbles
  • flour
  • bread crumbs
  • coffee beans
  • beans
  • different shapes of pasta
  • pom-poms
  • pop corn kernels or popped
  • Lego pieces
  • salt
  • dish-soap
  • beads
  • yarn/string
  • etc…

Have each student bring in a bottle from home filled with the contents of their choice so that you have enough bottle to compare. Match similar bottle shapes/sizes together for each group or match similar contents in different sized bottles for comparison.

You can also use these bottles as part of a Triple Beam Balance Activity (blog entry).

Dunkin’ for Density Challenge

Dunkin' for Density - finding the mass after the dunk tank.
Dunkin’ for Density – finding the mass after the dunk tank.

Updated for 2016: See blog entry

Introduction:

This is a wonderful problem solving and hands-on activity to use as part of your density unit. The students enjoy the challenge and have a solid understanding of density after completing this activity. Even though students quickly figure out how to make the canister float and sink, making the canister suspend is pretty challenging and requires a lot of trial and error and problem solving.

To qualify as suspending, the film canister needs to float just under the surface of the water, with a small portion of the top just breaking through. How I also verify that it is suspending is by pushing the film canister to the bottom of the tank, if it comes up very slowly to the surface, it counts – if it comes up quickly or stays towards the bottom, it doesn’t count. Students then need to figure out that if it comes up too quickly, they need to add to the mass, if it comes up too slowly, they need to remove some of the mass. It will take several tries to get it just right.

dunkin_1

Materials:

  • Dunkin’ for Density handout (1 page pdf) or (2 page pdf) and (link) to the original lesson from ScienceSpot.net
  • Triple Beam Balances
  • Container filled with water
  • Towels – the more the better!
  • Film canisters
    • one canister per 2 people works well, they can reuse the canisters if you don’t have enough to give each set of lab partners 3 canisters
    • if they reuse the canisters, be sure that they find the mass before they empty the contents
  • An assortment of small objects such as pennies, paper clips, stoppers, small pebbles, etc…
  • Calculators

dunkin_2

Procedures:

  1. Introduce the Dunkin’ for Density Challenge – their goal is to make the film canister float, suspend, and sink by placing contents inside of the film canister.
    1. Many students will say that the canister will float with nothing in it, but they must place a few objects in it for it to count 😉
    2. On a side note, a mini history lesson on film and cameras is fun to discuss since most students have never used a camera that used film
  2. Explain the procedures, review how to use the TBB, note that the film canister must seal completely and be air tight so that water doesn’t enter, and also demonstrate how to use the dunk tank properly and to dry off the canister before finding the mass.
  3. Do not give the students the value for the volume of the film canisters until they have collected their data. If the students know the volume of the film canister, they may figure out the mass needed to make the film canister’s density close to 1.0 g/cm3.
    1. The value is approximately 39 mL or 39 g/cm3 – verify with a large graduated cylinder that the film canister can fit inside of – or use an overflow can to find the volume (link).
    2. I will give the volume to each set of lab partners individually and ask that they don’t share that information with the class.
  4. Once students have calculated the density, collect class data on a spreadsheet projected on the board/screen.
  5. Discuss results – why did the film canister float, suspend, or sink in the tank of water? What relationships did you notice?
dunkin_results
Results show that densities close to 1.0 g/cm3 suspended.

For more lessons related to the Properties of Matter, click here (link)

Reading a Triple Beam Balance

Image: Ohaus Scale Reading Exercise
Image: Ohaus Scale Reading Exercise

Reading a Triple Beam Balance Worksheet (pdf) and Ohaus website (link)

This is a great interactive tutorial from Ohaus (link). Using the tutorial prior to using the triple beam balance in class significantly improved the student’s understanding of how to find, read, and record the mass of an object to the nearest 1/10th of a gram.

For the tutorial, each student works at their own pace and is given immediate feedback for each answer they submit. The problems are randomly generated and each student has a slightly different experience, as opposed to having each student answer the same set of problems. Students will also review place values for 100s, 10s, 1s, and 1/10ths. (Values for the 100ths place may appear in the answers, but students will only be assessed up to the 10ths place)

Here is nice video that gives a general overview on how to use the TBB:

Next Generation Science Standards, Science and Engineering Practices (SEP)

  • (SEP2) Practice 2 – Developing and Using Models
  • (SEP4) Practice 4 – Analyzing and Interpreting Data
  • (SEP5) Practice 5 – Using Mathematics and Computational Thinking