Saturday, May 7, 2011

What is a Lever?

A LEVER is a simple machine that is a bar (lever arm) resting on a turning point (fulcrum)

A lever is used to move or lift things.

Example: seesaw




Vocabulary: machine, lever, lever arm, bar, fulcrum, turning point



Materials

  • ruler (lever arm)
  • rectangular eraser (fulcrum)
  • pennies (load)


    Activity 1




      Directions

      • Have students place a ruler (lever arm) on top of an eraser (fulcrum) so that the eraser is under the middle of the ruler. (The ruler will be balanced.)
      • Have students stack 5 pennies on one end of the ruler.
      • Challenge the students to raise the pennies without touching the pennies. (They need to press down on the opposite end of the ruler.)
      • (Explain that the ruler is acting as a lever when they press down on the other end and it lifts the pennies.)
      • Try the same activity but place the 5 pennies on the other end of the ruler.
      • Challenge the students to raise the pennies without touching them.
      • Have the students explain why they were able to lift the pennies without touching them.


      Activity 2





      Directions

      • Have the students place 3 pennies on one end of the ruler.
      • Ask them to predict the minimum number of pennies that would have to be placed on the other end of the ruler to raise the 3 pennies. (They could write down their prediction.) (Answer: 3)
      • Have the students add pennies to the other side to test their prediction.
      • Were they correct? Why?
      • Try the same experiment with 7 pennies.


      Activity 3






      Directions
       
      • Have students place 3 pennies on one end of the ruler and 6 pennies on the other end of the ruler.
      • Challenge the students to lift the end with 3 pennies without adding or taking away pennies on either end.
      • If students are having trouble tell them that they can move the pennies but must keep 3 on one side of the ruler and 6 on the other side of the ruler.

      This can be accomplished by moving the heavier pile of pennies towards the fulcrum.



      Activity 4


      • Have students sketch/draw and label a seesaw (including the bar/lever arm and turning point/fulcrum. 
      • Have students sketch pictures of today's 3 previous lever activities in their science notebooks and explain how the lever worked in each activity. 
      • Have students visit a park and enjoy a real seesaw (a lever)! Have fun!



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      2 comments:

      1. Love it with a ruler! We just did this with a piece of left over wood trim and the boys matchbox cars haha!

        ReplyDelete
      2. Hello I've received this award Kreativ Blogger and now I'm passing it along to you. You can find it on my blog..
        http://thepurplefroggieclaystuff.blogspot.com/2011/05/ive-received-award.html

        Have a great day!

        Cindy

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