Barbara's Lesson Plans in Science


HOW CAN WE MAKE A SIMPLE DEVICE TO CHECK FOR HUMIDITY IN THE AIR?

GRADES: K-8

This lesson is very easy. It combines art and science, is easy to do, and helps a student check for humidity in the air. As with any science project students must be warned not to taste anything that is used in an experiment (this includes food). Explain that humidity is the amount of moisture in the air. Tell them when people talk about bad hair days, they are referring to the fact that certain types of hair frizzes when the humidity is very high.

MATERIALS:

METHOD:

  1. Have students make a drawing of a city if they live in one, or a rural scene if they happen to live there. Have them color the picture.
  2. Paste on one of the cobalt chloride pieces in an appropriate area. It is best for the teacher to do the pasting.
  3. In dry conditions the cobalt chloride strips will be blue. As the level of humidity in the air increases, the strips will react to the moisture and turn pink. The pinker the strip, the more moisture or humidity in the air.
  4. The pictures can be mounted and hung up.
  5. Strips can also be placed outside the window to compare the humidity outside the classroom to the humidity inside the classroom.


TO BE ABLE TO IDENTIFY A MYSTERY SUBSTANCE BY FINDING ITS PHYSICAL PROPERETIES

GRADES: K4 to 6

This project requires a little time and preparation on the part of the teacher, but in the long run provides invaluable science skills for the students. The students will be taking a trip to an imaginary newly discovered planet in the solar system. The class is broken up into cooperative teams of scientists consisting of a reader, writer, materials handler and an encourager. You inform your students that they are now going to Planet (pick a name) to investigate the surface of the planet. They will be working with their teams to record all the data that they can by investigating the substance that they will receive. Tell them that physical properties include, touch, smell, texture, state or phase, color, temperature, size, weight etc. Students should be familiar with the three states or phases of matter, solid, liquid and gas.

MATERIALS:

Oobleck a stubstance made with 3/4 cup cornstarch,4 ozs water and some food colouring. The name Oobleck comes from the book, "Bartholomew and the Oobleck", Dr. Seuss, 1949, 1977
  • small cups for the Oobleck
  • trays to place the materials on
  • newspapers to cover the desks
  • teacher made work sheet with activities
  • pennies
  • styrofoam balls
  • pieces of tooth pick
  • wooden craft sticks
  • pieces of wax paper
  • other various small objects for testing
  • hand lenses
  • handi wipes for clean-up

    METHOD:

    Teacher prepares the Oobleck at home and brings it into class. Before the lesson, the teacher puts the Oobleck in the cups and places the various materials to be used in testing the substance on the tray. Each materials handler from each of the scientific teams brings the tray to his team. The teacher then tells the students that they know about solids, liquids and gases, but on this planet something new has been discovered. They have to find out if this substance is different from the usual states of matter. The activity sheet is given out. The sheet is divided into two columns. In the first column is the test and the second column is their observations. Tell them that they must work cooperatively to collect all the data. Tests used are:
    1. Appearance, the colour, the weight, the texture of the substance.
    2. Feel of the substance as they put their finger slowly into the Oobleck.
    3. Feel of the substance as they push their finger quickly into the Oobleck.
    4. Pour some out on the wax paper. Does it pour like a liquid?
    5. Scrape some of it off. What does it look like. What does it look like after a few seconds?
    6. Trying picking up a piece of the Oobleck. How does it feel?
    7. Put some Oobleck into the palm of your hand and try to roll it into a small ball. What happens when you stop rolling it?
    8. Test the Oobleck with some of the small objects. Record what happens.
    9. Try to push some of the objects slowly and quickly over the surface of the Oobleck. Record your observations.
    When the group is done with their tests, initiate a discussion as to whether or not Oobleck can be classified as a solid or a liquid or both. The answers should be based upon their observations. Oobleck is a discrepant substance that displays both characteristics under different circumstances. It is a colloid. Colloids are substances that are composed of particles that are extremely small that are suspended in a suitable gas, liquid or solid. Oobleck can be easily cleaned. DO NOT POUR IT DOWN THE DRAIN

    UP, UP & AWAY: AIR EXERTS PRESSURE

    GRADES K-12

    This experiment shows that air exerts pressure. The title is funny, but the application is very real, and very scientific. You can't explain air pressure to a child and make it have any kind of meaning unless there is a clear application to go along with it. This experiment shows that air pressure applied to a large area has tremendous force--enough force to lift a teacher on a table supported by confined air.

    HYPOTHESIS:

    Do you think it is possible to lift a teacher on a table supported by confined air? (Most kids will say it is impossible).

    MATERIALS:

    METHOD:

    1. Make a cuff around the bag, approximately 3 inches wide.
    2. Keep the bag flat, and insert the straw. Leave about 5 inches of straw outside of the bag.
    3. Tape down the straw, making sure the straw is anchored down and can't move.
    4. Using the masking tape seal the bag up. Do not use a zip lock bag.
    5. Taping the bag shut, keep it flat like an envelope. Have the students check their bags for leaks by partially blowing it up.
    6. When they are sure that the bag is perfectly closed, remove all the air from it again, so that it is once again flat.
    7. Have the students kneel around the bottom table, placing their bags flat on the table with only the straws protruding over 5 or 6 inches over the edge.
    8. Once this is done, the students step away and the teacher puts the second table on top of the first, with the legs of the second table facing upward. The only thing separating the first table from the second are the bags.
    9. The teacher then climbs up onto the second table, sitting down in the center.
    10. The students (12-15) then return to the table and kneel down in front of their bags.
    11. At a signal, one..two..three, blow,... all the students blow into their drinking straws. The teacher has now been "blown up" by the students. (This actually works..the second table rises up from the first table).
    DISCUSSION:

    Students will understand that while each student is blowing air that doesn't press very hard against the inside of the bag, there is a very large area for the air to press against when a lot of bags work together. It is like a lot of little fingers all pressing against the table at the same time. If you get enough little fingers, you could lift a very large table and a very large teacher.

    Other questions to ask: If you had a large enough table and enough bags could you lift an elephant? As the table is lifted, what happens to the area where each individual bag touches the table? What happens to the total area where bags touch the table? Why do you think the table stops rising even though you keep blowing into the straw?


    PHYSICAL SCIENCE: INERTIA

    GRADES 4-9

    Inertia is the tendency of a body in motion to stay in motion, or for a body at rest to stay at rest. This experiment will show how inertia works in a very simple way for all children to understand. Students will run down a hallway from point A for 10 meters to point B and try to stop exactly on a line.

    Ask the students this question: Do you predict that you will be able to stop EXACTLY on the line at point B?

    MATERIALS:

    EXPERIMENT:
    1. Put down a piece of masking tape on the floor and label it point A.
    2. Measure 10 meters from point A, and put down another piece of masking tape and label it point B.
    3. Beginning at point A, have the student run as fast as he or she can to point B. The student should try to stop exactly on the masking tape at point B.
    4. One student should keep records as to how far over Point B each student went in centimeters.
    5. Afterwards, have the students explain what happened when they tried to stop.
    6. The students should then hypothesis why this occurred.
    CONCLUSION: Discuss the following with the students:

    The action of inertia is based on Newton's First Law of Motion, a scientific principle. The law states that a body at rest tends to stay at rest, and a body in motion tends to continue in a straight line at the same speed, unless some outside force acts on the body to change this condition. That is why you can't stop on the line and instead, continue over it!

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    Note : You may have seen some of my Lesson Plans on "Teachers Helping Teachers"