Download WaterThermometerInvestigation (1)

Science, Language & Community
Water Thermometer Investigation
A thermometer is an instrument that measures the temperature and it is one tool that we can use to
measure what the weather is like. Temperature is measured in a scale called Fahrenheit, used by most
people in the United States; in Celsius, used by scientists and by people in many other countries; or in
Kelvin, which is also used by scientists. We can also use simple water thermometers to observe the
differences in temperature.
In this activity, we will be building a water thermometer to learn how a thermometers work and to
investigate properties of water.
Materials
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Tap water
Rubbing alcohol (do not drink this)
Clear, narrow-necked plastic bottle (11-ounce water bottles work well)
Food coloring
Clear plastic drinking straw
Modeling clay, plastic putty, or UHU
Methods
1. Pour equal parts of tap water and rubbing alcohol into the bottle, filling about 1/8 to a 1/4 of the
bottle.
2. Add a couple of drops of food coloring and mix.
3. Put the straw in the bottle, but don't let the straw touch the bottom (do not drink the mixture).
4. Use the clay, putty, or UHU to seal the neck of the bottle, so the straw stays in place.
5. Now hold your hands on the bottle and watch what happens to the mixture in the bottle.
Why Does this Happen?
In the water thermometer, you created a sealed environment around the liquid.
This means that the water is surrounded by air (see Figure 1).
By putting your hands on the bottle, you warmed the mixture in our water
thermometer. The increased temperature caused the liquid to expand. However,
since the water thermometer created a sealed environment around the liquid,
there was nowhere for the water to go in the bottle as it expanded. The straw gives
the expanding water an area where it can expand. If the bottle were to get very
hot, the liquid would have come through the top of the straw.
Figure 1: Investigation Set Up
The expansion of liquid that we see in the water thermometer is called thermal expansion. Thermal
expansion is the tendency for matter (solids, liquids, and gases) to get bigger, or expand, as temperature
increases. All thermometers use thermal expansion to measure temperature.
In order to accurately read the temperature, you would need to use a real thermometer that is carefully
calibrated for (made to measure) temperature changes. The thermometer that we used for this
investigation is to demonstrate thermal expansion and to see how a thermometer works.
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Science, Language & Community
Molecular Science for Older Students
Our liquid mixture contains 1 part water and 1 part alcohol. Water and alcohol, like all substances, is made
up of molecules. An individual water molecule has the chemical formula H2O (2 hydrogen atoms and 1
oxygen atom). An individual alcohol molecule has the chemical formula OH (1 oxygen atom and 1
hydrogen atom). When the molecules are heated, their bonds stretch and expand, causing the liquid to
expand. What do you think happens if the liquid is cooled?
All thermometers use thermal expansion to measure temperature. This is possible because scientists know
the amount that common substances expand for every degree that temperatures rise. We use liquids in
most thermometers, rather than solids or gases, because liquids are more sensitive to changes in
temperature than solids and easier to see and control than gases.
Climate Change: Why Thermal Expansion Matters to Us
Thermal expansion helps to explain why it is likely that warmer global temperatures will cause sea levels to
rise. As the land and lower atmosphere on Earth warm, heat is transferred into ocean waters. We know that
when matter expands when it is heated because of thermal expansion. Therefore, we can hypothesize that
if the heat is transferred into the ocean waters, then the water will expand and sea levels will rise.
What are the possible impacts of sea level rise on small islands?
In a 2007 assessment of global climate change, scientists estimated that the global sea level will rise
between 18 and 59 centimeters by 2100. What could this mean for our communities on small islands in the
Pacific? Some places may lose a large portion of their land area. For example, the highest elevation in the
Marshall Islands is only 10 meters (or 1,000 centimeters). Other impacts may include:
 More frequent and intense flooding, storm surges, and erosion that may damage the infrastructure
and settlements that support island communities
 A decline in coastal conditions, like the erosion of beaches and coral bleaching, that may affect food
supply, tourism, and protection of the islands/atolls against storm surges
 Fewer clean water resources, which will make it more difficult to meet demand during dry seasons
 Increasing temperatures may cause non-native species to invade islands further north
Thermal expansion does not fully explain sea level rise.
Thermal expansion of ocean water explains about 70% to 75% of the rise in sea levels. The rest is mostly
due to the melting of glaciers on land. Melting of glaciers on land, like those in New Zealand and Norway,
releases water that might eventually enter the ocean and contribute to sea level rise. Also, increased
temperatures may stop ice from forming in some places and add water to the ocean. The melting of glaciers
floating in the ocean will not change the amount of water in the ocean.
Resources
Australian Academy of Science. (2008, May). Getting into hot water: Global warming and rising sea levels.
Retrieved from http://www.science.org.au/nova/082/082key.htm
California Energy Commission. (2006). Make a thermometer: Watch how a simple thermometer works.
Retrieved from http://energyquest.ca.gov/projects/thermometer.html
Pachauri, R.K., & Reisinger, A. (Eds.). (2007). Fourth assessment report of the Intergovernmental Panel on
Climate Change: Synthesis. Retrieved from
http://www.ipcc.ch/publications_and_data/ar4/syr/en/contents.html
Solomon, S., D. Qin, Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M. & Miller, H.L. (Eds.). (2007).
Fourth assessment report of the Intergovernmental Panel on Climate Change: The physical science
basis. Retrieved from http://www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html
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Warm Up Activity: T-Chart
Help students begin to think about what they know about the properties of water and what they want to
know about water by creating a T-Chart. Below are some example questions that your class could use to
build a T-Chart for this investigation.
 What do we know about water?
 What do we want to know that could tell us something about how this water thermometer will
behave?
Question and Hypothesis
If I put my hands around the bottle, the water will rise.
[QUESTION FORMATION]
What do we know about water that could tell us something about how this water thermometer will
behave?
Scientists form hypotheses in “if, then” statements.
For example: If I throw the ball up in the air, then it will fall to the ground.
What happened to the water in the thermometer when you placed the thermometer in warm water?
Explain.
What happened to the water in the thermometer when you placed the thermometer in the cold water?
Explain.
Self-Assessment Checklist
- I followed instructions to make a model of a thermometer.
- I observed the thermometer placed in warm and cold water.
- I recorded my observations.
- I explained what happened to the thermometer when it was placed in warm water.
- I explained what happened to the thermometer when it was placed in cold water.
Connect to Culture: Collecting Empirical Knowledge
In addition to conducting scientific investigations, students can gather local knowledge about the weather
from elders and long-time residents in their communities. This type of knowledge is called empirical
knowledge and is gained through careful observation from multiple vantage points over extended time.
Students can collect such information using interviews questions like these below:
1. How do the wind, clouds, and rain in your area change throughout the year?
2. How do they differ or vary by place, like closer to or farther from the ocean?
3. When you see a certain type of cloud or feel a certain type of wind, does that tell you something
about the weather?
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