Fortunate Fish
Luck be a red fish tonight.

Science is the observation, identification, description, experimental investigation, and theoretical explanation of natural phenomena. Over the last half millennium scientists have developed a method to aid them in learning about the Universe we inhabit. In this experiment you will use the scientific method to investigate Fortune Teller Fish. By testing one variable at a time, you will be able to determine why the “fish” behaves the way it does.

The steps in the scientific method are not necessarily sequential not all of them have to be performed to conduct a successful investigation of natural phenomena. Nonetheless, the steps are listed in a logical order below that could be followed from start to finish.

scientific method.JPG

Millennium – a period of 1000 years
Method – series of steps used to solve a problem
Phenomena – a fact, occurrence, or circumstance observed or observable
Observation – any information gathered using your senses
Hypothesis – educated guess; a well thought out solution to a problem
Variable – any factor in an experiment that could affect the results and is therefore tested separately.
Controlled Experiment – an experiment in which all variables but the one being tested are controlled in order to make the experiment fair and the results reliable.

Define the problem
What causes a fortune-telling fish to move in a person’s hand?

Research the topic
In order to better understand why a fortune-telling fish behaves the way it does it is important to understand the material it is made from and a few of its properties. Fortune-telling fish are made out of cellophane. Below is a definition of cellophane and questions about some of the words in its definition. With the help of the Internet research the answers to the questions below. Afterward, write a new definition of cellophane by using the research answers.

Cellophane – a thin, transparent film made from cellulose which has a low permeability to water.
1. What does it mean if a material is transparent?

2. What is a film?

3. What is cellulose?

4. What is permeability?

Use the answers to the four research questions to create a new definition for cellophane.

Cellophane –

Make Observations
Obtain a fortune telling fish and place it on your desk. In the space below describe its properties.

Place the fortune-telling fish in the palm of your hand. Explain its behavior.

Explain what is different about the palm of your hand compared to the table? That is, what variables are present when the fish is in your hand that are not present in the table?

Form Hypothesis
Form a hypothesis as to why the fish curls.

Design an experiment
Design a simple experiment to test why the fish curls. List your materials and write your method below. Hint: check out the available supplies.



After receiving approval from your instructor, conduct the experiment. Record the results of your experiment below – that is, say what happened and give details.

Draw Conclusions
Clearly state what causes the fish to behave the way it does in your hands.

Communicate Results
Recently Bob Vila, a scientist at Home Depot University, conducted an experiment with fortune-telling fish. He wants to know how your experiment compared with his. Read over Bob’s experiment carefully (see his abstract on the bottom half of this sheet) and then in the space below explain what you tell Bob.

Bob Vila
Home Depot University

An experiment was conducted to determine why Fortune Teller fish curl and twist when placed in the palm of a person’s hand. Three different variables were tested including water, heat and surface texture. The water was tested by placing the fish in a small Petri dish of water. The heat was tested by using a candle flame. The surface texture was tested by using sand paper. The final results of the experiment showed that water causes the fish to crinkle and curl. Heat and surface texture did not affect the fish. Hence, it is concluded that moisture in the palm of a person’s hand is what causes Fortune Teller fish to behave by curling and twisting.

Fortune-telling fish are made from cellophane, a thin, transparent film made from regenerated cellulose. When placed in your hand, the fortune-telling fish curls, twists, and bends due to a combination of water absorption and evaporation. First, the cellophane absorbs a small amount of moisture from your hand and then the heat from your hand causes some of the water absorbed in the fish to evaporate. The swelling ofthe fish due to absorption and the shrinking of the fish due to evaporation cause the movement observed. Given a small amount of water, the low permeability of cellophane to water ensures the material does not become soggy and creates a cycle of absorption and evaporation. As different parts of the fish come in contact with a person’s hand it swells and shrinks, and the forces involved with these two processes causes it to move in a variety of ways. Additionally, the lightness of the cellophane makes it very susceptible to air currents, which adds to the effect.

Figure 3: The top fortune-telling fish is reacting to water; the bottom one to heat created by a hand warmer.

Extension #1
A prediction is the expected outcome of a future event. For fun you are to create your own predictions for what the fortune-telling fish’s behavior means. In the table below list the action the fish performs and the meaning behind the action. Please ensure your comments are lighthearted. Have fun.


Extension #2
An inexpensive and convenient source of heat for the Fortune Telling Fish experiment is a store-bought hand warmer. When taken out of the package, the air activates a chemical reaction inside the bag which causes it to get gradually warmer and stay warm for hours. Student can research or make hypotheses about how the hand warmer works. A typical hand warmer has four main ingredients: iron powder, salt, activated charcoal and vermiculite. When the bag is opened the iron oxidizes in the presence of the oxygen in the air and produces heat. The salt acts as a catalyst to speed up the oxidation and produce heat quickly (but not too quickly). The carbon in the activated charcoal disperses the heat throughout the inside of the bag, just like the charcoal in a grill does. Finally, vermiculite is an insulator which helps to keep the heat in the bag.

Figure 6: An example of a store-bought hand warmer

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