Alaska Science Standards

Standard A1 - structure of matter

Standard A2 - physical changes in matter

Standard B1 - observation, inference, prediction, collect data

Alaska Math Standards

Statistics and Probability 1 (levels 5-7 and 8-10) Collect, organize and display data in a variety of forms including tables and graphs

Science Key Concepts

• Water is the only material that exists naturally in three states - solid (ice), liquid, and gas (water vapor)
• Water is made up of atoms of hydrogen and oxygen forming molecules
• An atom is the smallest part of an individual element that has all the properties of that element
• A molecule is the smallest part of a substance that has all the properties of that substance and is composed of more than one atom
• Water has adhesive and cohesive properties that influence how it behaves
• Adhesion is the attraction of unlike substances on a molecular level
• Cohesion is the attraction of like substances
• The cohesive properties of water affect the surface tension of water molecules allowing them to do such things as mound and support certain objects heavier than water
• These adhesive and cohesive properties of water may be affected by the addition of other substances
• Capillary action, the movement of water up a wick, is a result of adhesion and cohesion
• Cohesive properties (surface tension) of water affect its surface allowing the water to do such things as mound and support certain objects heavier than water. It is caused by attraction of the hydrogen atoms of one water molecule to the oxygen atoms of other water molecules
• The adhesive and cohesive properties of water are affected by the addition of other substances.

• Ask students what they know about water, what it is and how it behaves (bring up states of matter and water cycle including evaporation and condensation with students if they don't do it themselves)
• NOTE: If students do not have a grasp of the states of water, water cycle, evaporation and condensation do AIMS "Mini Water Cycle" from Water Precious Water (page 23-) Students will observe changes in bags over next 3-4 days.
• Ask students how many drops of water they think they can be put on a penny before it will overflow
• Have each team record their predictions on the worksheet

• Give each student a penny and an eye dropper
• YOUNGER STUDENTS: Have students CAREFULLY add drops to the top of the penny
• OLDER STUDENTS: Ask student what should be done to make comparison fair, so that one person's number can be compared to another's (list variables to be controlled)
• Count the drops used
• Observe what happens
• Repeat the process two more times
• Entering data onto the bar graph on board
• OLDER STUDENTS: Find the average of their three trials and enter this into the table on a chart or the board
• YOUNGER STUDENTS: May want to put all three numbers on the board
• Draw the shape of the water from the side

• Have each team share their observations, predictions, and results. Be sure to discuss the shape of the mound
• Ask students to make inferences on worksheet about why they observed what they did (why do they think that they were able to get so many drops on their pennies/why do they think the water was the shape it was)
• Ask if everyone got the same results (refer to graph)
• Discuss why they think this might be (see how many variables they can list that could have caused the different numbers)

• Have students pick up a cup of water and a paper clip for each team
• Have them work together to see if they can lay a paper clip on the surface of a cup of water
• After they have had time to explore themselves demonstrate how to do it if they have not figured out a method
• Ask them to observe very carefully what the paper clip looks like on the water and record this on the worksheet

• Ask students to share their strategies
• Ask what observations they made
• Ask students what their ideas (inferences) are about why they think the water could support the paper clip

• Ask students to predict what they think will happen if they add 5 drops of soap to the cup with the paper clip floating on the surface
• Discuss why they think so
• Have them record their predictions on the worksheet

• Have each team use an eyedropper to add 5 drops of liquid detergent to their cup of water on which the paper clip is still floating
• Observe what happens
• Record on worksheet

• Ask students to share their observations
• Ask them to make an inference about why they think it might have happened

• OLDER STUDENTS -WATER MOLECULE SIMULATION:

• Have some of the students link arms to be water molecules and have others be paper clips that are supported by the water
• Show the overhead transparency: Hydrogen Bonding
• Tell students that what the water is doing is called "hydrogen bonding"
• Ask other students to be soap molecules and show you what they think happened when the soap molecules were added
• Start the "Properties of water" chart. Be sure understanding that is written has been agreed to by all students

   

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• Ask students to keep in mind what they have already found out about water and predict what they think will happen to the string if they add a drop of soap inside the center of the circle of string laying on the water surface
• Record predictions on worksheet
• Next have them predict what will happen if they put a drop of liquid detergent outside the loop
• Record your predictions on your worksheet

• Have each team of students get a tub of water, thread or light string and a small cup of soap and eyedropper
• Have students carefully lay a 10 inch loop of string on the surface of the water so that it forms a circle (Be sure they lay it carefully so that it continues to float)
• One member of the team should then place a few drops of detergent INSIDE the loop.
• Observe and record observations by drawing BEFORE and AFTER pictures on worksheets
• Repeat if necessary for students to clearly see what happened
• Dump out the water and CAREFULLY clean tubs to remove all traces of detergent
• Fill the tub with new clean water
• Get a new loop of thread and place it on the water in an open circle
• Now have one member of the team put one or two drops of detergent OUTSIDE the loop
• Observe and record observations again with BEFORE and AFTER pictures on worksheets
• Repeat if necessary so that students can see clearly what happened

• Ask students to share their observations
• Ask them for their inferences about why the string did what it did (Try to develop the idea of hydrogen bonding and surface tension)

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• Ask students if they think water will behave the same on all surfaces
• Discuss. Ask them to explain their ideas
• Divide the class into small groups of 3-4 students. Have each student get the following supplies:
  • Piece of waxed paper
  • Piece of aluminum foil
  • Straw
  • Toothpick
  • Cup of water with eyedropper
  • Cup of rubbing alcohol with eyedropper
  • Small cup of detergent with eyedropper
  • WARN THEM NOT TO MIX UP EYEDROPPERS

• Have students use the eyedropper and put 5 separate drops of water on the waxed paper
• Play with the water drops using straw and toothpick
• Observe and record observations on worksheet. Add a drop of detergent to the water drops and observe what happens
• Record observations on worksheet
• Put 5 drops on water on the piece of aluminum foil
• Play with it using straw and toothpick
• Observe and record observations on worksheet. Add a drop of detergent to the water drops and observe what happens
• Record observations on worksheet
• Add a drop of alcohol to the water drops and observe what happens
• Record observations on worksheet

• Ask for observations. Discuss
• Add to the properties of water chart

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• Ask students if based on their previous observations, they think rubbing alcohol will behave the same on waxed paper and aluminum foil as the water did
• Ask why they think so

• Have students use the eyedropper to put 5 drops of rubbing alcohol on the waxed paper
• Play with it using straw and toothpick
• Observe and record observations on worksheet. Add a drop of detergent to the alcohol drops and observe what happens
• Record observations on worksheet
• Put 5 drops on rubbing alcohol on the piece of aluminum foil
• Play with it using straw and toothpick
• Observe and record observations on worksheet.
• Add a drop of detergent to the alcohol drops and observe what happens
• Record observations on worksheet

• Share observations with the whole group.
• How were the liquids alike? How were they different?
• How were the surfaces alike? How were they different?
• What are students ideas about what caused the differences

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• Ask students what they think will happen if you put a strip of paper towel into cup of colored water.
• Discuss
• Ask students why they think so

• Have each pair of students take strips of paper towel and a cup of colored water
• Have students dip the paper towel strip into the colored water and observe what happens
• Pass out hand lenses and suggest that they might want to use them to look at the paper more carefully
• Generalize
• Ask students for their observations and ideas about why they think the water traveled upward (discuss adhesion and cohesion vs. gravity)
• Ask students what they think would happen if they put a line of marking pen on the paper towel before they dipped it (demonstrate)
• Show students how to tape strips of Popsicle sticks over glass of water
• Suggest that they make the pen marks above the water line

• Have students explore with pens and paper
• Tape interesting strips on a piece of copy paper for sharing later
• Walk around as students are exploring and encourage them to use a variety of colors including black and leave them in the water long enough for the pigments to separate

• Have students share their observations and discoveries
• Ask for their ideas are about what was happening with the water and the pigments
• Remind them to consider what they have learned about adhesion and cohesion of water molecules (adhesion and cohesion vs. gravity again)
• Final Generalize
• Review property chart and add any new ideas
• Ask questions to lead students to understand that many of the behaviors of water are due to the fact that it is attracted to itself (cohesion) and may be attracted (adhesion) or repelled by other materials

• Liquid Explorations Packet
• Mini-watercycle packet
• Process skills checklist
• Journal entry - draw and write new ideas about water, including as many specific examples as you can think of
• Student individual or small group interview - tell me what you have learned about water (have water and materials there for support)
• Design an invention that moves water from one place to another. Use what you have learned about adhesion and cohesion
• Tell a story from the point of view of a water drop. Include as much as you can about water, especially states of matter and adhesion and cohesion

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