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


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’ 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



  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 ūüėČ
    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?
Results show that densities close to 1.0 g/cm3 suspended.

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

Cup Stacking Collaboration Challenge

Cup Stacking Challenge


  • Students will collaborate, problem solve, and persevere¬†to accomplish each challenge

Materials – per group of 3-4 students

  • Task Cards – cut apart, laminate, and secure with a metal ring or brass brad
  • 6 cups
  • 1 rubber band
  • 4-6 pieces of string of equal length

This is one of the team building exercises I plan to use with my 6th graders during the first week of school. Many variations of this lesson can be found online. For this version, I created 6 different challenges for the students to tackle – each one increasing in difficulty. Not every group will get to complete all 6 challenges, and that is OK. The objective is to learn to work together as a team and not give up.

Updated: Pictures September 2015

Working as a team to complete a task
Working as a team to complete a task
Trying to pick up a cup that fell over.
Trying to pick up a cup that fell over.
Almost done with Challenge #4!
Almost done with Challenge #4!

Discussion & Reflection

  1. Which challenge was the easiest for you group to complete? The most difficult? Why?
  2. Did your techniques change as you advanced to each challenge? Explain why or why not.
  3. Describe a technique that worked best within your group.
  4. Compare using two hands vs. one hand when holding the string to guide the cups. List advantages and disadvantages for each.
  5. Compare using verbal and nonverbal communication, what were some of the challenges your group faced?
  6. If you were to complete this activity again, what would your group do differently? What would you do the same?
  7. Why are collaboration and communication skills important characteristics for scientists to have?
  8. Did you feel like giving up at any point? How did you and your group deal with frustration?

Blood Types Flashcards & Games

I used this hands-on activity as a review/reinforcement with my 7th graders and it really helped them understand the different blood types, about blood donation, and basic Punnett Squares. Plus they had fun playing the games and making up their own games.


  • One set of laminated flashcards¬†(pdf) per person, or two sets shared in a group of 4 students
  • pencil and lined paper to make Punnett Squares

All of the instructions and different games to play are explained in the handout. Some examples are: Who can donate? Punnett Square Practice, Identification, Memory, and Matching.

Other ways to use the cards:

  • Flashcards – ¬†Students can print their own at home and use them to study
  • You can set up a station/rotation to play the¬†games as they are, or as ‘make your own’ game stations. Or a combination of both.¬†Place¬†one game at each station and have the students rotate every 7-10 minutes (see below for logistics)
  • Rotation Directions¬†– students will rotate from table to table and learn to play the game at each station
    • Need a group¬†of 4 students at each station.
    • When it is time to rotate, only 2 go to the next station, and 2 stay.
    • The 2 that stay are the experts on that game.
    • The 2 experts¬†teach the 2 novices how to play when they rotate¬†to the table.
    • When it is time to rotate, the 2 experts who¬†stayed go to the next group, and the novices¬†are now the experts and teach the 2 new novices that came to the station.
  • Quiz-Quiz Trade
    • give each student a RBC card¬†and have them identify it, then trade
    • give each student a blood-type card and ask for the genotype (ie AA or AO)
    • Or mix both decks and play both games
  • Find your Partner
    • give half or your¬†class Blood Type Cards and the other half of the class RBC cards and have them find the matching¬†set

Interactive Links for further practice

  • Blood Typing Game – can you make the right choice? (link)
  • Are you my blood type? can you find the donor? (link)
  • Emergency Room – figure out the blood type and correct transfusion (link)
  • NatGeo – interactive heart (link)
  • BrainPOP:¬†¬†Blood¬†&¬†Blood Pressure

If you use this lesson in your classroom, I am always happy to hear how it went!

For related lesson plans, please visit my Life Science page.

Quiz, Quiz, Trade – Apollo Missions

Recently, I tried the “Quiz, Quiz, Trade” (QQT) method of review to help my students study for their Apollo Missions assessment. How does it work? See the video below:



Before starting the activity, I modeled how to ask, answer, and trade using¬†student volunteers. We also discussed ‘quizzing etiquette’. What do you do if your partner is stuck? How can you give clues to help jog their memories? What are some things that you should or should NOT say if someone can’t answer the question, even with hints? After you go over the answer with your partner, are there any tips to help your partner remember the answer? I stressed the importance of helping each other learn. It is not just about getting the answers right or wrong and no one ‘wins’ if they answered the most questions¬†correctly.

Each student was given one question to start the activity. Because I had more questions than students in my class, after a student makes 3 trades, I had the students hand in/trade their cards with me to introduce new questions into the mix as needed. Some students will answer more questions than others, and that is ok. The students quizzed/traded with each other for about 20 minutes. While they were quizzing each other, they kept track of which questions they answered correctly, and which ones they needed to work on using this handout: Quiz, Quiz, Trade Numbers  (pdf)

Sample Question Card
Sample Question Card

For the second half of the review activity, I divided the class into two teams. I would randomly pick one question to ask each team. Before I asked the question, I announced the number of the question I was going to ask them. The students on each team then looked at their sheets to see who had that answered that numbered question correctly and chose one person to come up to answer the question. If no one had the numbered¬†question answered correctly (or did not have¬†a chance to answer it during QQT), they would volunteer a ‘tribute’ to try to answer the question. If the first¬†team answers correctly after I read the question to the class, they earned a point. If answered incorrectly, the other team had a chance to steal and earn the point.¬†We really enjoyed playing QQT and I plan on using it again in a variety of ways.

This is also a great way to practice vocabulary words. Using index cards, students can write the vocab word on one side and the definition on the other. You can also use it for identification skills – show a picture¬†on one side, and the identification on the other. For example, one side can have a picture of a beaker, and the other side will have the word¬†‘beaker’ to practice identifying lab equipment. Other ideas include: plant identification, constellation identification, cloud identification, metric conversions or abbreviations, etc…