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Liquid Crystal Sheets (12x12 inch) NGSS

Buy 11 or more for $23.95 each
  • Liquid Crystal Sheet, 30-35C Transition (12x12 inch)
    Item #: LC-3035A
  • Buy 11 or more for $23.95 each
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  • *Backordered: 08/27/19
  • Liquid Crystal Sheet, 25-30C Transition (12x12 inch)
    Item #: LC-2530A
  • Buy 11 or more for $23.95 each
  • - +
  • Liquid Crystal Sheet, 20-25C Transition (12x12 inch)
    Item #: LC-2025A
  • Buy 11 or more for $23.95 each
  • - +
These laminated sheets of liquid crystal are temperature sensitive. Available in a variety of temperature ranges.

Description

These laminated sheets of liquid crystal are temperature sensitive. The plastic sheets remain black except for a five-degree temperature range in which they display a series of colors that reflect the actual temperature of the crystal. Using sheets that change colors at different temperatures opens up a world of possibilities for experimentation. The material can be easily cut with scissors. Self-adhesive backing. Please note that the effects of temperature on each of the liquid crystals depend upon the ambient temperature of the surroundings.

LIQUID CRYSTAL SHEET, 20-25oC TRANSITION (68-77oF)
This liquid crystal sheet changes color at a transition point just about below room temperature. Depending on the ambient temperature of your room, this liquid crystal will change its color by the heat of your hand, an ice cube or a can of cold soda.

LIQUID CRYSTAL SHEET, 25-30oC TRANSITION (77-86oF)
This liquid crystal sheet is so sensitive that it can detect the heat print your hand leaves behind! Place your hand on a book for a few seconds, then remove your hand and place the liquid crystal sheet over the spot where your hand was located. Observe as the liquid crystal changes color and makes visible your hand's heat print. Or, simply touch the material and observe the print left by the heat of your hand.

LIQUID CRYSTAL SHEET, 30-35oC TRANSITION (86-95oF)
This liquid crystal sheet changes color just slightly below body temperature. Placing the sheet near a gentle heat source or warming it with your hands causes the liquid crystal to change color, indicating areas of differing temperature. Perfect for showing the effect of samples higher than room temperature, such as hot coffee and heat from a light bulb. Try holding a strip against your arm and observe your veins!

Sizes are approximate. Order by temperature range.

Video

Lesson Ideas

Download the pdf of this lesson!

Why do liquid crystals change color with temperature?

The long, cigar shaped, molecules of a liquid crystal align themselves into orderly flat planes. The molecules in each flat plane are oriented at a slight angle from the molecules in the plane below it. Eventually, as the stack builds up and each layer is off set by a slight twisting from the one below it, two layers will have the same orientation. The distance between these two aligned layers is called the pitch. When white light is directed at this stack of molecules, the wavelength of light equal to this pitch distance is reflected back. At cold temperatures the pitch is far apart; red light is reflected back. At higher temperatures the molecules move faster and the layers twist more, causing the pitch to become shorter, reflecting blue light. Each liquid crystal has only a few degrees of temperature where the organization is such that light is reflected back. On either side of this temperature range, all light is absorbed and the liquid crystal appears black.

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Reviews

6 reviews
Heat Sensitive Materials
Review star icon Review star icon Review star icon Review star icon Review star icon Apr 18, 2019
Thanks to E. I. and a number of other sources I was able to put together an outreach presentation demonstrating the properties and uses of thermochromes, including liquid crystals. Be sure to have a hair dryer or two on hand. (Remember hair dryers pull a lot of current so use separate circuits fitted with separate circuit breakers.) These substances change their chemical structure when subjected to different temperatures dependent upon the chemical. Often, it is merely a change in the degree of conjugation (alternating double and single bonds) in the molecular structure. The higher the degree of conjugation the lower the amount of energy required for electrons to "move" along the conjugation. Often this is in the visible region of the spectrum. Avoiding quantum mechanics, we can simply say that the temperature of the substance affects the color of that substance. We use the color changing paper, color changing Crazy Arron's Thinking Putty, and liquid crystal sheets available from E. I. along with color changing cups available from several sources such as Amazon.com (color changing straws, cups, spoons, and other items can be purchased as well). We also purchased liquid crystal "fever gauges" from a pharmacy, aquarium thermometers from a pet store, and I have a liquid crystal room temperature gauge that I received somewhere from the Royal Society of Chemistry a long time ago. These products are useful in showing applications of liquid crystals. We begin with the color changing paper leaving up to the guests to figure out what to do with it. They quickly find its the warmth of their hands and almost immediately use the hair dryers to see what happens. We then move on to the Thinking Putty, which the all like and many have at home, where they play with it to see that it to changes color with temperature. Of course, off to the hair dryers they go. Laying it out flat and heating one side they find that the side heated is one color and the back is the original color. We move on to the color changing cups, spoons, straws, etc. where they find that some of the objects must be cooled rather than warmed for a color change to be observed. This sort of "messes with their minds." With some discussion and guiding questions, they realize that the color changing items do not contain the same substance. We then pass out the three liquid crystal sheets (we cut the 12 x 12 sheets into smaller squares) with the temperature range on the back of each sheet. It is fun to see them use their hands, ice, warm water, hot water to see which sheets will change color and to what colors, if they change at all. And, of course, off to the hair dryers one more time. Finally, we show them the aquarium, fever, and temperature liquid crystal temperature gauges. They use the aquarium sensors to measure the temperature of a beaker of water, they measure each others temperature (have them wipe the sensor with a sanitized wipe before changing partners), and they look at the room sensor to measure the temperature of the room. What a great set of products! I encourage E. I. to acquire some of these other color changing products as well as keep providing the ones they do now. Great way to introduce how temperature can affect a substance's structure and therefore, the color observed.
Kenneth Lyle

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Look at mine!
Review star icon Review star icon Review star icon Review star icon Review star icon Oct 24, 2014
Students in science classes really enjoy playing with these! I was teaching a unit on thermodynamics and careers involving 'heat/energy' knowledge when I brought these and an overhead on liquid crystal technology out. I cut each sheet into 36 2" squares for the students to take home. Always a hit!
LaDonna

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Liquid Crystal sheet
Review star icon Review star icon Review star icon Review star icon Review star icon Jul 1, 2014
Very prompt. Shipping cost was high.
Claude Hartman

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none
Review star icon Review star icon Review star icon Review star icon Review star icon Jun 3, 2013
Exactly what I wanted and shipped most promptly.
Ron Strong

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Liquids Crystal Sheet
Review star icon Review star icon Review star icon Review star icon Review star icon Jun 1, 2013
I just received my 12"x12" Liquid Crystal Sheet with the 25*-30*C transition, along with several other captivating items I ordered from Educational Innovations. I bought these things so I could expose my 3 1/2 year old niece to science without the explanations that would be over her head at this age. I couldn't be happier with the outcome. She has taken such a shine to everything I got, but especially the Liquid Crystal Sheet and the UV Color Changing Beads. I can almost see the gears turning in her brain as she tries to deduce how these things work. Every time she comes over now, the first thing she says is "Can we go play with the liquid crystal and the beads?" Thanks to Educational Innovations' products, my niece has started down a path that is full of wonder and excitement. I can't wait to decide what I'm going to get next. I highly recommend this product.
William Willis

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Great Products!
Review star icon Review star icon Review star icon Review star icon Review star icon Feb 18, 2013
I ordered all three temperatures and it was interesting to see and hear the reactions of students when they saw an image at a lower temperature but did not see one at a higher temperature. Only a few students were able to generate an image on the highest temperature sheet. We attributed that to the fact that some people actually have a higher body temperature than the "normal" 37 degree C. I don't know if that is totally true, but it seems to make sense. I cut the sheets in diagonals so even people with large hands would be able to see an entire handprint. The only reason for a 4 rating and not 5? The sheets are pricey for a single sheet.
Gary Patterson

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NGSS

This product will support your students' understanding of the Next Generation Science Standards (NGSS)*, as shown in the table below.

Elementary Middle School High School

2-PS1-1

Students can use Liquid Crystal Sheets to plan and conduct an investigation to describe and classify different kinds of materials by their observable properties.

2-PS1-4

Students can use Liquid Crystal Sheets to collect data to construct an argument with evidence that some changes caused by heating or cooling can be reversed and some cannot.

4-PS3-2

Students can use Liquid Crystal Sheets to make observations to provide evidence that energy can be transferred from place to place by heat currents.

MS-PS3-3

Students can use Liquid Crystal Sheets s to apply scientific principles to design, construct, and test a device that either minimizes or maximizes thermal energy transfer.

MS-PS3-4

Students can use Liquid Crystal Sheets for an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample.

DCI-MS/PS3.A: Definitions of Energy.

The temperature is a measure of the average kinetic energy of particles of matter. The Liquid Crystal Sheets creates a beautiful thermal print when acted on by an object, such as your hand. Each color represents a different temperature.

HS-PS3-4

Students can use Liquid Crystal Sheets to plan and conduct an investigation to provide evidence that the transfer of thermal energy when two components of different temperature are combined within a closed system results in a more uniform energy distribution among the components in the system (Second Law of Thermodynamics).

Suggested Science Idea(s)

4-PS3-2

Students can place their hand on the Liquid Crystal Sheets to observe the transfer of heat energy to the surface of the temperature sensitive material. Each color represents a different temperature.

MS-PS3-3

Each color represents a different temperature as students test a device that either minimizes or maximizes thermal energy transfer. There are three temperature ranges of sheets available for investigations.

MS-PS3-4

Students can use the Liquid Crystal Sheets for an investigation to determine the relationships among the energy transferred by different objects.

HS-PS3-4

Students can use the Liquid Crystal Sheets for an investigation to determine the relationships among the energy transferred by different objects.

 

* NGSS is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of, and do not endorse, this product.

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