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Just Add Water: Science Experiments With H2O

EducationWorld is pleased to feature this K-6 science lesson adapted from School Volunteer Handbook: A Simple Guide for K-6 Teachers and Parents, by Yael Calhoun and Elizabeth Q. Finlinson (Lila Press, 2011).

The lesson plan, shared with the permission of the authors, is a great example of a short activity with simple instructions that appeals to a diverse group of parent interests and teacher needs. The activity is an ideal one for implementation by classroom volunteers.

See other School Volunteer Handbook activities:
A Lesson in Character: Connect With Yourself
Be the Boss: A Lesson Plan On Managing Feelings
Lesson to Celebrate Diversity: The Unity Necklace

About the authors

Yael Calhoun, MA, MS, RYT, is an author and educator who has taught preschool through college. She also has worked as an environmental planner and has written over a dozen books. Currently, she is a cofounder and the Executive Director of GreenTREE Yoga, a nonprofit committed to bringing the benefits of yoga to diverse populations.

Elizabeth Q. Finlinson, LCSW,is a Licensed Clinical Social Worker and has worked as a school therapist, volunteer coordinator, and as a private practitioner specializing in children and families. She teaches character education and physical education and is an active school volunteer.

Subjects

Science

Grade

K-6

Brief Description

Get students excited about scientific inquiry--specifically, observing and asking questions about water. Understanding molecular structure is not critical to having fun with science; the key is observation and curiosity.

Objectives

Students will

  • Practice observation — the key to science.
  • Notice new things about a substance we may take for granted – water!

Time: 30 minutes

Materials Needed

  • Wide-bottom plastic cups for water
  • Toothpicks
  • Wax paper
  • Plastic wrap
  • Newspaper
  • Squares of newsprint
  • Magnifying glass
  • A plate
  • Box of paper clips or straight pins

Lesson Plan

Preparation

  1. Read through the activity below and try it at home first.
  2. Find “interesting water facts” to share with the class.
  3. Learn about water molecules: All you really need to know to do this activity is that the water molecule is made from the bonding of two atoms of hydrogen to one atom of oxygen. Because it has positive (hydrogen) and negative (oxygen) charges, it sticks or bonds to other water molecules.
  4. Cut for each student a 6-inch square of newsprint and plastic wrap.
  5. Cut for each student a 12-inch sheet of wax paper.

The Activity

Part 1: Discussion Points (10 minutes)

  1. What is water? (Draw the water molecule on the board. [See right.])
  2. Who needs it? What uses water on our planet? Where do we find it?
  3. How does it move around the planet?
  4. Ask a person to come and stand next to you. Choosing someone who is not yet involved or is being disruptive can be a good classroom management technique. Have people try to guess how much of that person is comprised of water. (It is about 70 percent, which includes the water in your bones.) How much of our planet is covered in water? (About 70 percent.)
  5. Ask students what they like to do that involves water.
  6. Set boundaries. “Spills may happen, but let’s work hard not to spill a drop.” Explain to the students that we can only do this activity if we are careful. You have special things you want to do with the water today, and everyone needs to do the activity together. Anyone who chooses not to follow your directions is making a choice to be dismissed from the activity. (Dismissed students will copy a page about water from a book in the back of the room.) Ask a student to repeat what you have just said. Ask if anyone has any questions about it. This discussion is an important step. Some classes are not used to hands-on activities and could quickly lose sight of your expectations.

Part 2: Exploring Water

1. Adhesion (water drops sticking together): 5 minutes

Distribute:

  • a sheet of newspaper folded so that it covers the desk;
  • a square of waxed paper and several toothpicks; and,
  • 1/3 cup of water for each small group of students.

Explore for two minutes: Dip a toothpick into the water and put six drops on the waxed paper. Use a toothpick to poke and move the water drops on the waxed paper for a few minutes.

Guide: Suggest that the students do the following:

  • Pull a small drop across the paper with a toothpick. Let students explore, undirected for a few minutes.
  • Ask them to break the drops apart into six drops and then into many smaller drops.
  • Pull the little drops across to one corner and make one large drop.

Explain: You just observed the bonding (sticking) of water molecules due to the positive atom (hydrogen) bonding to the negative atom (oxygen). You then broke those bonds by applying pressure with the toothpick which makes smaller drops. What are some examples of this you might see outside?

2. Light refraction (water drops as magnifiers): 5 minutes

Get set: Give each student the plastic wrap and newspaper squares.

Big drops: Use the toothpick to transfer several drops onto the wrap to make a large drop.

Watch it grow: Hold the water drop on the plastic over the newsprint and observe. Compare the print without the water drop. Why is there a difference? The water molecules stick together and form a lens shape. This shape concentrates the light, just like a magnifying glass.

A lesson from nature: Look at the shape of the lens of a large magnifying glass. Discuss how it magnifies because light waves are bent or refracted – the same way a water drop magnifies the magazine print.

3. Surface tension (water drops forming a “skin”): 5 minutes

Set it up: Fill a glass with water. Have everyone agree it is full to the brim. Hold up the pins (or paperclips). Ask how many pins they think can be added to the water without it spilling.

Predictions: “Science is about observation and making predictions. We’ve observed how water sticks and how it magnifies, so now let’s predict how it might behave as we add pins. Write your prediction on a slip of paper and initial the paper, without telling anyone what you wrote.” Collect the papers. Then ask if anyone wants her prediction written on the board.

Water math: Begin to add one pin at a time. Students can watch carefully as the surface tension finally breaks and the water spills. Compare the number of pins in the water to the student predictions.

Extend the lesson

Predict and observe
Challenge the students to try this water exploration at home and to consider the following:

  • Would the size of the glass affect the number of pins?
  • Does the temperature of the water affect the behavior of water?
  • What other variables or factors could we change?

In science, we just change one variable at a time, so we know which variable caused the change. This is called the scientific method.

Colorful celery
Set up a jar of water colored with food coloring. Put a stalk of leafy celery or a white flower in the jar. Measure and record what happens each day for three days. The water will move up the small tubes, or capillaries, in the celery or flower, in part because the water sticks or adheres to the sides of the tubes. The process of evaporation also causes the water to go up.

Encourage the students to find their own questions and set up experiments at home or in the classroom. What happens if you change the color of the water after one day? Does water move as fast up a stalk of celery with or without leaves? How about if you put one stalk in the sun and one in the dark?

Students can show the data on bar graphs.

Boat races
Set up a rectangular pan or container of water several inches deep. Sprinkle a corner of the water with pepper. Place a drop of dish soap in the middle of the pepper. What happens? The soap breaks the surface tension and the pepper scatters.

Cut out flat, four-inch paper “boats” with a “v” in the back. Students can decorate the boats. Now put two paper boats in one corner for a race. Ask the students how they could get the boats to move. After soliciting their ideas, place a drop of soap inside the “v”.

Watch as the boats race across the top of the water for the same reason. What questions could you now ask? Does the thickness of the paper affect the distance? Does the type of soap? Does the size of the “v”? The temperature of the water? Record and present the data using charts and graphs.

Ask and observe — it’s all science!

Share a book
River Dance by Thomas Locker (available for under $10 online) is a book of beautiful prose and breathtaking photographs on the water cycle, inviting comments from students in grades K-6.

 

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