Density Rainbow: Difference between revisions

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{| class="wikitable" style="color:black; background-color:#ddd; margin-left: auto; float:right"
{| class="wikitable" style="color:black; background-color:#ddd; margin-left: auto; float:right"
| [[Physics]], [[Chemistry]]:
| [[Physics]], [[Chemistry]]:
| Density
| Density, Buoyancy
|-
|-
| Grade Range:
| Grade Range:
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|}
|}


This space is intended to describe the demonstration that is here. Please use this space to describe in short the demonstration, making sure to mention here if it will require any additional safety equipment or how easily it can be adjusted for varied grade levels.
'''''This Demonstration is Still Under Construction'''''
Use this page as a base layout for editing the wiki. Feel free to copy the layout onto other pages, and to put the content as needed into the page.
 
Elementary students love this demonstration, and are often very interested in watching the liquids sort. This demonstration has two methods to present it; one with a variety of solutions, and the other using only sugar solutions.


== Materials ==
== Materials ==
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===Method B===
===Method B===
# Measure out 100mL of water into each of the small beakers. Add three drops of food coloring
# Measure out 100mL of water into each of the small beakers. Add three drops of food coloring to four of the beakers, with each getting only one of the colors.
# Add sugar to each of the colored beakers. Give two teaspoons to red, five to yellow, eight to green, and eleven to blue. Mix each one thoroughly, rinsing or wiping the spoon between beakers so that a beaker doesn't get too much or too little sugar.
# In the big beaker, first add the blue solution. Then, to add the rest of the solutions in color order, ending with clear, by pouring them slowly over the back of the spoon to prevent splashing and mixing. If done correctly, the solutions will stack on each other, creating a rainbow!




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== Additional Information ==
== Additional Information ==


* Any extra tidbits that do not fit into other sections
* This pairs well with the [[Cartesian Diver]] demonstration.
* This demonstration is a part of the (insert [[Stage Show]] here)
== Age ==
 
Elementary School
 
== Format ==
 
Hands-on
 
== Materials ==
 
    Sugar
    Three small cups to mix solutions in
    One large (~8oz), clear cup that will be easy to see into (thinner is better)
    Three types of food coloring
    A tablespoon measuring spoon
    A plastic spoon
    A funnel
    A supply of clean water if you will be presenting multiple times
    A water basin to clean materials between performances
    A towel to dry off the measuring spoon
 
== Safety Precautions ==
 
Science Theatre demonstrators must keep the safety of themselves and their audience in mind at all times. All Science Theatre demonstrators must have read through the Safety Training page. The ST Safety Box with first aid kit, fire extinguisher, etc. should always be available to demonstrators. Always wear safety gloves, glasses, and a labcoat if handling chemicals; always perform potentially dangerous demonstrations at a safe distance from the audience; and always keep a very close eye on any volunteers you call from the audience. Demonstrators should wear goggles and lab coats, and the ST general safety box should be available to them. While the materials involved in this demonstration are not particularly dangerous, care should always be exercised to ensure the safety of the audience and to avoid messes. The sugar solutions should not be consumed!
 
== Preparation ==
 
Make sure a large basin of clean water is available. You should use this water to clean the materials between performances. If the cleaning water becomes too saturated with food coloring, replace it. Make sure clean water is available for making the solutions.
 
== Demonstration ==
 
In the three small cups, add one, two, and three tablespoons of sugar, respectively. Make sure the measuring spoon is dry before you insert it in the sugar! Be sure to remember which glasses have the most and least sugar. You could write out signs to place next to the glasses to help the audience remember which one is most dense. Add three tablespoons of water to each cup. Stir the sugar-water solutions very well (for about 30s each) to dissolve as much sugar as possible. Add about two drops of different food coloring to each cup. Because yellow food coloring tends not to be very strong, it should be added to the least-dense solution, if used at all, so that it's not overwhelmed by seepage from a higher layer.
 
Add the highest density solution to the large, clear cup. Now place the plastic spoon upside down in the clear cup so that the bottom of the spoon just touches the top of the solution. Slowly and carefully pour the medium-density solution over the back of the spoon on top of the high-density layer. This is necessary because it is important to avoid letting solutions plunge into previous layers, as the food colorings will mix and the rainbow layering will not be preserved. Repeat the process carefully with the low-density layer. If done correctly, the clear gas will have well-defined (though not sharp) layers of different density solutions of different colors.
 
== What to Say ==


<!--
As you're preparing the sugar solutions, let the audience see that the sugar dissolves into the water. You may want to discuss saturation: ask the audience what would happen if you introduced a large amount of sugar into a small amount of water.
As you're preparing the sugar solutions, let the audience see that the sugar dissolves into the water. You may want to discuss saturation: ask the audience what would happen if you introduced a large amount of sugar into a small amount of water.


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Before you layer the solutions, ask the audience if they think any of your three solutions could float on top of the others. Make sure they can guess the ordering correctly. Ask them why you need to add the solutions so slowly and carefully.
Before you layer the solutions, ask the audience if they think any of your three solutions could float on top of the others. Make sure they can guess the ordering correctly. Ask them why you need to add the solutions so slowly and carefully.


Finally, ask the audience if they think it would be easier to swim in very salty water than in a regular swimming pool. You could introduce the concept of viscosity to explain that, even if it is easier to float in saltwater, it would be more difficult to propel yourself. You could ask the audience to think about swimming in honey or mud. Make sure the audience understands that typical saltwater doesn't have high enough salinity for this effect to be significant for human swimmers, but that it might be important for microscopic organisms in seawater [2].
Finally, ask the audience if they think it would be easier to swim in very salty water than in a regular swimming pool. You could introduce the concept of viscosity to explain that, even if it is easier to float in saltwater, it would be more difficult to propel yourself. You could ask the audience to think about swimming in honey or mud. Make sure the audience understands that typical saltwater doesn't have high enough salinity for this effect to be significant for human swimmers, but that it might be important for microscopic organisms in seawater [2]. -->
 
== Why it is ==
 
== Real Life Examples ==

Revision as of 18:45, 15 April 2016

Physics, Chemistry: Density, Buoyancy
Grade Range: Elementary School
Format: Hands-on

This Demonstration is Still Under Construction

Elementary students love this demonstration, and are often very interested in watching the liquids sort. This demonstration has two methods to present it; one with a variety of solutions, and the other using only sugar solutions.

Materials

Method A

  • Graduated Cylinder (500mL)
  • Various Liquids, such as:
    • Liquid Soap
    • Water
    • Corn Syrup
    • Lamp Oil
    • Vegetable Oil
    • Glue
  • Small objects to put in (Paper clips, bits of wood, plastic, etc.)

Method B

  • 1 Large Beaker (600 mL)
  • 5 Small Beakers (140-150 mL)
  • Sugar
  • Water
  • Spoon
  • Food Dye (Red, Yellow, Blue, Green)

Safety Precautions

Please read the Liquid Chemical section of the Demonstration Safety page before performing this demonstration.


Demonstration

Method A

  1. Set the graduated cylinder on a table with a bin or tablecloth underneath to catch any spills. Add 100 mL of water to the cylinder before the start of the event.
  2. Let students add one of the other liquids in (but only a small amount) and watch where it ends up. Is it above or below the water? As more liquids are added, they will sort themselves by density, and students will be able to see some clear distinctions between the liquids!
  3. Let students know that the density of something is equal to its mass divided by the volume it takes up. Give them a small object and ask them to predict where it will float in the cylinder before dropping it in. Was their prediction correct?

Method B

  1. Measure out 100mL of water into each of the small beakers. Add three drops of food coloring to four of the beakers, with each getting only one of the colors.
  2. Add sugar to each of the colored beakers. Give two teaspoons to red, five to yellow, eight to green, and eleven to blue. Mix each one thoroughly, rinsing or wiping the spoon between beakers so that a beaker doesn't get too much or too little sugar.
  3. In the big beaker, first add the blue solution. Then, to add the rest of the solutions in color order, ending with clear, by pouring them slowly over the back of the spoon to prevent splashing and mixing. If done correctly, the solutions will stack on each other, creating a rainbow!


Why This Works

Short Explanation

This is where you would provide a basic, easy-to-understand explanation of the demonstration. Try not to use too much "Science Jargon", and if needed add any explanation tips, like comparing the demo to something kids are familiar with.

Full Explanation

This is where you will explain the demonstration in full, and provide all additional information that pertains to the demo. Unlike the short explanation above, this should be worded so someone who is familiar with the topics might understand it. If needed, you can provide equations and citations for additional sources of information on the topic. This is also where you will find some answers for trickier questions, such as "How does a plane fly upside-down?" for the Bernoulli's Principle demo. If you want to add a floating box for equations, copy the following:

This will give you a floating box.
The box will be centered for you.

Additional Information


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