Applied Science - Science and Math(1A)
Lab 

   
OBJECTIVES:
  • Comparing different magnifiers.
  • Exploring organisms using a magnifier.
VOCABULARY:
MATERIALS:

Students learn how to compare different hand lenses.

BACKGROUND:

Observation is a trained skill. The more practice students have in observing details, the better they will be able to transfer the skill.

Students should be told that just to know the name of an object, does not mean that you understand  the significance of that object. All people named "John" or "Sally’" are not the same.  They will all have their own characteristics like size, age, and shape.

This lab helps the students to use  scientific tools to describe objects in more details.  Students at this age may not understand the significance of a magnifier or how they are used.  Magnification can help the students focus on details and help them observe and describe better.  Students need to take time as they look at the entire object in detail.

A magnifier is considered a simple microscope composed of one lens. Magnifiers enlarge objects by using the properties of light.  Different magnifiers will enlarge an object differently, depending on the shape and size of the lens.     

PROCEDURE:
  1. If you have purchased the kit, give each pair of students a bag of sealife containing a sea cookie, marine snail, seastar, and coral. (If you do not have these items find appropriate substitutes.) Have students look at the bag of items before they use the magnifying glass. They can also draw what it looks like on paper or several students can use the board.
      
  2. Next, give each student a hand lens. We suggest you put a string through the hole so students can wear this one around their neck.   Demonstrate how to use a magnifying glass. Tell students to put the magnifying glass to one eye, and cover the other eye with their hand. When they look at an object they should move the object, not the hand lens. Most of your students will insist on moving the hand lens and it may be hard to convince them otherwise. Remember, you are just introducing the correct procedure. Don't demand it. After a while it will become natural to look at objects that way. Students with glasses may find it more difficult.  Tell children that they are focusing on an object to make it clearer.  You may want then just to look at their fingernail.  Collect this magnifier after they have looked at several items around the room or on their body.  .  
      
  3. Instruct students to look at the items in their bag of sealife. Make sure to explain the need of detailed observations. Have selected students come to the board and draw a picture of what they saw with the hand lens. 
      
  4. Give students the chance to use all three magnifiers labeled 3X, 5X, and 15x.   Explain that the objective of the lab is to see which hand lens, from a choice of several magnifiers in the module, magnifies the largest. Don't tell the student the magnification of each. Let them observe the sealife with all the magnifiers. You may want the students to PREDICT which one they think makes the larger image before they actually look. Most children will predict that the larger the magnifier, the larger it magnifies. The magnifier with the 3 loupes (15 x) makes the objects the largest; each lens is 5x and when they are together you get the total magnification. The largest lens is actually only three times magnification.  You may want to make a 1 cm dot and have the students look at it with all three magnifiers after they have done the exercise.  This might make it clearer which magnifier creates the largest image. .  
      
  5. Have a discussion with the students of their observations. When observing the sea cookie, they should be able to see the little holes that are all over the organisms. The side with the two large holes is where the mouth (one in center) and its anus ("poop" hole) are located. The opposite side is where the star shaped pattern is. The coral has little holes all over where the individual coral "polyps" live. The clam lives in the marine environment. The seastar is related to the sea cookie, and it also has holes all over its structure. Little hair-like extensions come from these holes when the organism is alive. The extensions help the seastar move.

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