Teaching Science Process Skills Using Mealworms

Mealworms

Yum! Yum!

By

Jill Bailer, Ed.D.

Pamela Esprivalo Harrell, Ed.D.

For permission contact:

Pamela Harrell

1155 Union Circle 310740

Denton, TX 76203

Mealworms: Yum! Yum!

Rational

Mealworms: Yum! Yum! provides a fresh approach for learning science process skills. Not just a collection of activities, it is a carefully planned, step by step approach using a Do – Talk – Do or learning cycle philosophy. First, the students are given an activity to introduce a new process skill. After the activity, the content is introduced and is followed by a “hands-on” investigation to reinforce the application of the science process skill and concept that is being developed.

As the student moves through the activities and investigations, they will sequentially build on previous knowledge and processes they have experienced first hand. They will learn by doing. At the end of the lessons, the students will have acquired skills necessary to conduct their own investigation and should have in their repertoire of knowledge all of the science process skills needed to conduct any investigation.

Organization of the Book

Observational Journals

Your students’ study of mealworms can be recorded in several different ways. For older or more advanced “scientists” we have included the pages “Setting Up an Observational Journal” and “My Mealworm Journal.” These pages give students the information needed to set up observational journals and begin their study of mealworms. These journals might be kept in conjunction with the process skills that are taught in the rest of the book or as an entirely separate activity.

For younger or less experienced “scientists” we have included “Sample Observational Journal” pages, which guide students through observations, drawings, and simple explorations. Again, these journals may be kept in conjunction with or separate from the activities in the book.

Sequence of Activities

Many middle school students are uncomfortable observing a colony with both mealworms and beetles in it at first. To help students conquer their fear and ease them into working with the mealworms, we have set up the first lesson so that the students observe one mealworm (they don’t have to touch it) and gradually progress to the pupae and then to the beetle. After the first lesson, then the colonies can be introduced, but again, with only the 2-5 mealworms – no beetles. Most students become comfortable with the mealworms after several days and are very excited when their mealworms pupate and the beetles finally emerge. It is at this time that we usually use the diagram of the life cycle and explain the process of complete metamorphosis, relating it to a familiar insect (the butterfly) and its larvae (the caterpillar).

The process skill activities take the students through the process skills needed to conduct their own independent investigation. The last section in the book is “Conducting an Experiment.” In this section, we have a template for the students to use as they conduct their own investigation. In addition, we have included three long-term experiments as examples of investigations students might conduct.

Setting Up a Classroom Mealworm Colony

Tenebrio molitor larvae can be obtained from any biological supply company or local pet store. Containers made of glass, hard plastic, or metal are suitable for housing. Plastic pails, plastic shoeboxes, glass aquaria, and metal coffee cans are appropriate containers. The important constraint with regard to housing the mealworms is to use a container, which cannot be eaten through, as these critters do have teeth. Containers made of cardboard or other types of paper or lightweight plastic are not suitable.

Mealworms will eat just about any type of grain. About six centimeters of wheat bran or oatmeal (regular, not instant or quick cooking) in the bottom of a glass canning jar or plastic shoebox will sustain a colony of mealworms for several weeks. Mixtures of foods that are intended for human consumption (such as oats) are less likely to contain contaminates (such as mites) that can destroy a mealworm colony.

Mealworms are highly efficient at conserving water. They secrete a solid dropping about the size of a pepper flake, so only a small amount of moisture is needed. Lay slices of apple, potato, or carrot over the surface of the colony to provide fluids for the mealworms. Cover the food and mealworms with a folded paper towel and sprinkle lightly with water once or twice a week. The mealworms will gather between the layers of toweling. Do not keep a top on the colony. This will cause mold to grow on the food, and the colony will have to be transferred to a new container.

Mealworms thrive in a warm environment of 80° to 90° F. Over time, a build up of powdery residue will appear in the container. This residue, called frass, consists of mealworm wastes and eggs. Sift this out using a colander, window screen, or tea strainer. Keep the frass in a separate container and add food and a water source. The eggs will hatch. When the larvae are easy to see, transfer them to the parent colony.

Setting Up an Individual Mealworm Colony

Mealworm observations have been done with many of our classes. Students (especially middle school boys) seem to take more ownership in the colony they are observing if they are responsible for the care of the colony. Set up colonies in the small wax-coated bathroom cups. In the cup, place about 4-5 centimeters of food, a small piece of fruit or vegetable for water, and 2-5 mealworms for each student. Although the cups are paper, the wax seems to keep the mealworms from chewing through. We have tried the 2 oz. portion cups that can be obtained from warehouse clubs, but the mealworms really like this type of plastic and chew through it overnight.

Setting Up an Observational Journal

Keeping an observational journal is something that scientists do that students can do, too. Many scientists report they have reviewed journals of their early experiments and found new questions and ideas to explore. Albert Szent-Gyorgyi, a Nobel Prize laureate for Physiology or Medicine in 1937, stated, “Discovery consist of seeing what everybody has seen and thinking what nobody has thought.” Making and recording observations are skills that every student can be trained to do, and these skills will help them in their future endeavors, whether they are scientific endeavors or not.

Students need a booklet of some sort. It can be a folder, a composition book, or even some notebook paper stapled together. The first page should be a title page. Be sure the student’s name and other important information is on this page.

A good observational journal contains a minimum of 2-3 observations each week. Each entry should include the date of the observation, a count of the colony members, and any changes that are observed from one day to the next.

A number of simple, labeled drawings and sketches that visually communicate observations should be included. These drawings do not have to be artistic, but they must be as accurate as possible.

The observational journal should contain the activities and experiments that are conducted with the mealworms over the course of the study. Students should also write down any questions, feelings, predictions, and inferences that occur to them.

WHAT ARE YOU LOOKING AT?

Snake CaterpillarEarthworm

Directions: Study the pictures above. Write some words that describe each animal. Use words that apply to the picture and not to what you might know about the animal. Confine your answers to what you can see on this paper.

Snake
Caterpillar
Earthworm

How are the animals similar?

How are the animals different?

Teacher Talk for Scientific Observations

Jane Goodall, a noted anthropologist who studies chimpanzees, said, “Patient observations are the most important part of science.” All scientific study starts with an observation. It is an important tool both in science and in our daily lives. Scientists use two types of observation: qualitative and quantitative. Qualitative observations describe qualities of an object while quantitative observations count, measure, time, or find the quantities of things. It is important to be as accurate and as thoughtful as possible whenever you are observing.

Qualitative observations use all five senses: touch, sight, taste, hearing, and smell. Qualitative observations use the senses to identify qualities and characteristics of what is being observed. Good observations are ones that can be replicated by others. They are factual in nature and are never based on an individual’s opinion. In the next four activities, the students will practice making qualitative observations for the mealworm, pupa, and darkling beetle.

Caution! It is important that students never place anything in their mouth in science class unless told to do so by the teacher.

OBSERVING MEALWORMS

Your teacher will give you a container with a mealworm in it. The mealworm will not hurt you in any way. It does not carry or transmit any diseases. They are very fragile and easily hurt. You must be very gentle with this animal. They are soft and must be handled carefully so as not to injure them.

Directions: Observe the mealworm you have been given.

Use as many senses as possible to describe it.

Sense
Sight
Smell
Touch
Hearing
Taste

1. How is this mealworm similar to the animals you observed in the activity Whatcha’ Looking At?

2. Which of the animals in Whatcha’ Looking At? Might be closely related to the mealworm? Explain your answer.

Use a magnifying glass to observe your mealworm. Draw in the box below. Make your drawing as realistic as possible.

MY MEALWORM

NAME OF MY MEALWORM

______

OBSERVING STRANGE THINGS

OBSERVING AN INSECT PUPA

Observe the pupa your teacher has placed at your table. Draw it below, describe it using your senses and then compare it with the mealworm from the previous lessons.

Drawing of a Pupa

Description of this puma using your senses (sight, hearing, taste, touch, smell).

How is this puma different from the mealworm your observed?

How is this puma similar to the mealworm you observed?

OBSERVING A DARKLING BEETLE

Observe the beetle your teacher has placed at your table. Draw it below, describe it using your senses and then compare it with the mealworm and puma you previously observed.

Drawing of a Bettle

Description of this beetle using your senses (sight, hearing, taste, touch, smell).
How is this beetle different from the mealworm and puma?
How is this bettle similar to the mealworm and puma
Pretend you have a pen pal in a remote part of the world where they have never seen a mealworm, puma, or darkling beetle before. Write them a letter describing these animals.

YOU CAN COUNT ON IT

BEEGRASSHOPPERMOSQUITO

Directions: Observe the insects above. Name four observable characteristics that they have in common and list them in the “Observable Characteristics” chart below. Record the number each insect possesses.

Observable Characteristics / Bee / Grasshopper / Mosquito

All insects have three body segments, six legs, and two antennae. Additionally, many species of insects have 2-4 wings. Look at one of your darkling beetles and compare it to the information above.

Is the darkling beetle an insect?

How do you know?

Teacher Talk for Quantitative Observations

In the first set of activities, the students were asked to describe the qualities and characteristics of the animals using their senses. These types of observations are known as qualitative observations. In contrast, quantitative observations deal with counting, measuring, and timing. Scientists, in general, prefer quantitative observations because they are more precise and accurate. The data obtained by the students in this activity are quantitative because they involve the counting of inset body parts. In the next two activities, the students will practice making quantitative observations as they measure the members of their colony and time how fast their mealworm can crawl.

Quantitative Observations of

a Mealworm Colony

In the previous activities you have been using your senses to observe the mealworms. In this activity, you will make quantitative observations of two mealworms in your colony and share your results with your partners. Measure your mealworms weekly to keep a record of their growth.

Remember, quantitative observations deal with quantities or numbers. To make quantitative observations, you must either count or measure.

Measure the length of the longest mealworm in your colony and the shortest mealworm in your colony. Place the information in the chart below. Remember to measure in millimeters.

Be sure to indicate in the chart when the mealworms changed to pupa.

My Mealworms / Week 1
Length in mm / Week 2
Length in mm / Week 3
Length in mm / Week 4
Length in mm / Week 5
Length in mm / Week 6
Length in mm
Shortest
Longest
My Partner’s Mealworms / Week 1
Length in mm / Week 2
Length in mm / Week 3
Length in mm / Week 4
Length in mm / Week 5
Length in mm / Week 6
Length in mm
Shortest
Longest

How long did your mealworms get before they changed into pupae?
Just before mealworms change into pupae, they experience a reduction in length. Did you observe any difference in the overall length of your mealworms at that time?
Why do you think this reduction might happen?

THE MEALWORM 100

Another kind of quantitative observation involves using a clock or a stopwatch.

Directions:

Make a racecourse for one of your most active mealworms with two rulers or pencils.

Make the racecourse 100 mm. Anything longer than this length will tire out the mealworm.

Place your mealworm at one end of the racecourse and time how long it takes it to get to the other end.

Do this three times with the same mealworm.

Place your lab group’s information in the data table below.

Mealworm Timed Trials

Mealworm Names / Trial 1 /

Trial 2

/ Trial 3 / Average

Describe how your mealworm ran the race.
What did it do while on the racetrack?
What did you do to help your mealworm complete the race?

CAN YOU EXPLAIN THAT?

Directions: Read the following observations and make a logical guess that might explain what was observed.

Every time Raul poured the food containing the mealworms on a piece of wax paper, the mealworms on top of the food would immediately begin to crawl under the food.

Can you explain that?

______

One day Hai picked up a piece of a potato in the mealworm food. There were mealworms under the potato.

Can you explain that?

______

Maria let two beetles crawl on her hand. She noticed that if she turned her hand upside down using slowing motion, the beetles would not fall off.

Can you explain that?

______

John noticed the tail end of some beetles appeared to be different from the other beetles.

Can you explain that?

______

Janet placed a mealworm in a jar filled with mealworm food. After two weeks, she poured the jar of mealworm food containing the mealworm on a piece of wax paper. Instead of the mealworm, she found a much shorter, fatter creature, which didn’t look like the mealworm at all.

Can you explain that?

______

As Pablo poured his cereal containing the mealworms on the wax paper, he noticed something like dried up skin.

Can you explain that?

______

Aaron filled the bottom of a plastic bowl with cereal. One side of the bowl hi filled with corn flakes. On the other side of the bowl his poured rice. He placed five mealworms in the middle of each type of cereal. When he came back the next day, he found eight mealworms in the corn flakes.

Can you explain that?

______

Sophie placed a slice of carrot in the mealworm’s food. In the next two weeks, she found many dried skins in the food.

Can you explain that?

______

Teacher Talk for Making Inferences

An inference is an explanation of an observation. Good inferences are not just wild guesses; they are logical explanations of the observation. Often, there is more than once logical inference that explains an observation. As more observations are made, original inferences can be changed because inferences are always tentative. Based on new observations, scientists may change the original inference.

Many times students are confused about the difference between observations and inferences. As we have discussed in the previous activities, observations use the five senses and are factional in nature. Observations do not change from one person to the next. Everyone should be able to agree on the observations made. Inferences, however, are logical explanations and can be influenced by knowledge, experience, and opinion. As long as the inference is logical, it is not wrong. Often, inferences are made better when new observations are acquired. The inference either gains support or is revised to fit the new information.

HOT TUBS AND COLD SHOWERS

Research Question: How do mealworms respond to temperature change?

Materials:

21-Quart size resealable bagsgraduated cylinder

5 Mealwormsaluminum pan or

Damp paper towelplastic shoe box