Rainbow Test Tubes Activity

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Problem: How many colors can be created by starting with red, yellow, and blue solutions?

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Updated Jan. 10, 2017 with results:

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Results 2016-17

Materials per group of 3-4 students:

  • Student Handout RainbowTestTubesPublic (pdf)
  • Spreadsheet to collect data (excel – public)
  • 9-10 test tubes with test tube rack
  • Erlenmeyer flasks filled with red, yellow, and blue solutions of food coloring and water
    • 5 drops of food coloring per 200 mL (25 per 1L)
  • 3 x 25 mL Graduated Cylinders
  • 3 x 10 mL Graduated Cylinders
  • pipette
  • beaker filled with clean water
  • large beaker for used water
  • this activity took 2x 50 minute class periods

rainbowlabsetupflasks

This lab is an updated version of the classic Rainbow Lab (link) that has been around since the 80’s (Measuring Liquid Volume with a Graduated Cylinder 1988). I used this for many years with my 5th graders, and previously with my 6th graders in the early 2000’s. Now that I am teaching 6th grade again, I wanted to make it more open ended and challenging. The purpose of the original version of the lab was twofold: First – could they follow directions carefully to make a rainbow? Second – how precisely can they measure liquid volume?

rainbowlabsetup

For the new version of this lab, I created new objectives and assessed the students based on their problem solving, collaboration, and measuring skills.

Objectives:

  • Students will be able to precisely measure liquids with a graduated cylinder
  • Students will be able to create their own lab procedures using the given parameters to guide them
  • Students will create new mixtures and solutions
  • Students will be able to record accurate data
  • Students will collaborate and problem solve to achieve a common goal
  • Students will test, evaluate, and select the best proportions to create the colors orange, green, and purple
    • each group made 3-4 different combinations for each color and had to, as a group, determine which combinations of primary colors created the best secondary colors
  • Students will follow proper lab procedures to avoid color contamination
  • Students will record and analyze data from the whole grade and compare their findings to the averages from each group, what patterns or trends did they notice in the data?
  • Students will create their own ‘designer’ color and share it with the class
    • this was fun way to wrap up the activity, we had a ‘fashion’ show with each group coming up to the front of the room to showcase their newly created and named colors
    • if time allowed, at the end we made a rainbow with each student holding their test tube and standing next to a person who had a color similar to their own, from Red to Purple
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Visual assessment – all test tubes are even and you can quickly see that each color has a volume of 25mL.
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Candle Observation Lab

candle_observation_lab

Materials – per 2 students

  • Student Handout (Candle Observations)
  • votive candle
  • small beaker
  • large beaker
  • ruler
  • matches & beaker with water for spent matches
    • I light the candles for the students in this age group (6th)

candle_observation_2

Procedures

  1. Discuss how candles work and the fire triangle (link)
  2. Discuss combustion and the chemical reactions that takes place when a candle burns
  3. Explain the lab procedures and remind students of safety protocols
  4. Students will record qualitative and quantitative observations of an unlit candle (5 minutes), burning candle (10 minutes), and a covered burning candle until it goes out and the wax hardens (5 minutes)
    • all students will place the larger beaker over the candle at the same time and watch as the candle goes out
  5. Share observations and discuss
rtemagicc_condensingcandle-burning
Image via The Naked Scientist

I like to use this lab as part of my physical and chemical changes unit, it is such a classic and the kids make some great observations and ask lots of good questions.

Links:

Physical and Chemical Changes Sorting Activity

Physical_vs_Chemical_Changes_Sorting_Activity

Materials

  • Physical and Chemical Changes Sorting Worksheet & Cards (pdf)
    • Laminate and cut cards apart, place in zip-top bags
      • 1 set per 2-3 students
    • Answers for Physical Change are: cracking eggs, slicing bread, ice  melting, glass breaking, boiling water, fresh lemonade, mowing lawn (cutting the grass)
  • Optional – privacy screen made of one manila folder cut in half and stapled together

View my Properties of Matter resources for related lessons (page)

This is a fun partner activity that I use as part of my Chemistry unit to get students thinking about the differences between physical and chemical changes. Each pair of students is given a set of cards with images and descriptions of either a physical change or a chemical change. (see photo above)

Each pair goes through the cards and discusses/decides where the each card will be placed. Once they have categorized the cards, students call me over verify their work – I will either say “Yes, they are all in the correct category!” or “Not quite yet, try again.” I give a small clue each time I come over. For example, I will say something along the lines of “You have 2 in the incorrect column” or “You have too many in the Physical Change category, which ones should be moved to the Chemical Change category?” or “Two cards need to be flip/flopped to the other category, all the other cards have been placed correctly” or “All of the cards that are placed in the Chemical Change group belong there, but not all of them are there quite yet, what else can you move to that category?” – I won’t tell them the specifics of what needs to be changed. This forces the students to re-evaluate their choices and make changes as needed until all of their cards in the correct category.

Every few minutes, I will give the whole class a clue. This allows them to check their progress and verify one answer at a time. One card that many students have difficulty with is the boiling water card – and that is usually the first clue I will give out once I have had a chance to check every group’s progress. Each pair of students continues working together until all the cards are placed in the correct category. Once I’ve verified their placements, they add the answers to their notes and answer the questions for the activity and we discuss our results.

Students sorting physical & chemical change cards

 

Physical & Chemical Properties vs Physical & Chemical Changes Foldable

pdf
8 1/2 x 14 Foldable

Materials

  • Physical & Chemical Properties vs Physical & Chemical Changes Foldable Notes – (link)
  • Reinforcement page (pdf)
  • Glue
  • Scissors

How to use the foldable:

  1. This activity can be done with or without a partner
  2. Cut the tabs on the dotted guide lines, but do not fold yet, instead keep the paper flat
  3. Page 3 of the document contains the notes, Page 4 is the answer key
  4. The notes are not grouped together correctly – cut out each piece of information along the dotted lines
  5. Place the notes into the correct boxes under the corresponding tabs
  6. Do not glue anything yet, just a dry fit at this point
  7. Discuss the answers
  8. Glue the correct pieces in order, move the incorrect pieces
  9. When done,  fold the tabs so they meet in the middle
  10. Glue into notebook