The Engineering Place (K-20 Outreach)

Making a Thermometer (4th-6th)

Lesson plan developed by Elizabeth Goodson

Objective: The students will observe how a thermometer works and then use the scientific method to determine which is the coldest cup of water from 3 cups.

Overview:

• Scientific Method
• Temperature
• Energy (measuring energy)

Materials:

• Tap water
• Rubbing alcohol
• Clear, narrow-necked plastic bottle
• Food coloring
• Clear plastic drinking straw
• Modeling clay
• Styrofoam cups
• Hot water
• Ice
• Salt

Background Information: Make 7 sets of equipment for the experiment with 3 cups and a thermometer in each set. Set up making the thermometer stuff.

Activity (Explore):

Begin by talking about energy:

• Heat is a kind of energy.
• Thermometers are tools used to measure temperature.
• We are going to see how a thermometer works by making one.
• Then we will use thermometers in a short experiment using the scientific method.

Procedure:

1. Equal parts of water and alcohol.
2. Add food coloring and mix.
3. Insert straw and secure with play dough or clay.
4. Either place hands on the bottom of the bottle or place in warm water and watch the level rise in the straw.

Discussion: Explain that the liquid expands and causes the water to rise in the straw. This is a true thermometer but it has not been calibrated so that we can use it to take measurements. We will use other calibrated thermometers for our experiment.

Questions:

Q: What are the steps to the Scientific Method?

A:

1. The Problem — Ask questions and gather facts.
2. The Hypothesis — Make a reasonable guess to the problem.
3. The Experiment — Plan (this includes a material list) and conduct the test.
4. Draw Conclusions — Gather data and compare to the hypothesis.
5. Investigate Further — Determine if data can be replicated or if others found similar results.

Q: What is the Scientific Law?

A: General statement which explains the experiment and why it came out that way.

Q: Which cup of liquid will be the coldest?

Ans/Discovery: Have each group write their hypothesis down on a sheet of paper and set aside. Then the students should take each cup's temperature and record the results. Have students compare results to their hypothesis. Gather all students data and compare — can the results be replicated?

Closure: Scientists use the scientific method every time they perform an experiment.

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