Probability

Designed by: Christi Jones and Jeanna Hoffman,
Satchel Ford Elementary School

Core Curriculum Objective:  Record data from experiments using tools, such as spinners and colored tiles/cubes and use the data to predict which of the events is more likely to occur if the experiment is repeated.  (2SP2-1)

Grade level:    Second          Subject:  Math

Overview:  Students will explore the concept of probability by picking colored bears out of a bag with different dollar values.  Students will make fair and unfair spinners and record data after spinning each one 20 times.  Students will be able to determine whether an event is likely or unlikely to happen. 

Focus Question:  How can we predict what is the most likely to happen?

Time Frame: 2 class periods (50 minutes each)

Resources/ Materials:  

brown bag

8 red bears

3 yellow bears

1 blue bear

spinner sheet - see example below

paper clips (one/student)

pencils

overhead transparency spinner - make an overhead transparency of the spinner sheet below

overhead projector

                                           www.mathleague.com/help/percent/percent.htm#whatisanevent

6) Culminating Assessment: Students will make a fair and unfair
spinner.  Students will use each spinner 20 times and record the results.  Students will write an explanation of their findings.  Teacher will score the explanations using the following rubric:

7)  Instructional Activities: 

Activity One: Prior to teaching this lesson, go to the web site http://www.mathleague.com/help/percent/percent.htm#whatisanevent for the definition of probability events and some examples.  Ask the students if they have ever heard of the word “probability”.  Ask the students if they have ever gone to the fair.  Tell them that when they go to the fair the games they play are hard to win.  The chances of winning are slimmer than losing.  The probability of winning a game at the fair is normally not good.

Teacher will show bag filled with bears and tell students what is inside.  Explain to the students that they are going to be on a game show and that they are going to be able to pull bears out of a  bag and win imaginary money.  Explain that different color bears are worth different amounts.  Red bears are worth $5, yellow bears are  worth $7 and the blue bear is worth $10.  The children who are picked to play in the game have to choose the color bear they think they are going to grab out of the bag.  Tell the students if they grab the same color they win the money, but if they do not grab the same color they lose. 

Randomly choose a student to come to the front of the room.  Ask him or her to think of the color bear they will probably pick out of the bag.  Once they have chosen a bear, ask them why they chose it.  Have the child grab a color from the bag.  After a color is chosen, lead the children into a discussion on probability.  Then have a second child come to the front and choose a color.  Before they grab from the bag have them explain to the class why they chose that color.  Review probability again using the terms, "unlikely, likely, certain and impossible".  Then have the child choose a color from the bag.  Ask why they chose that particular color and provide feedback.  Repeat until all the bears have been chosen. 

Discuss which bear was most likely and least likely to be picked.  Also ask why the blue bear was worth $10. 

Activity Two: As a class review the probability terms from activity one.  Show the students a spinner and ask them what it is and how it is used. To make a spinner, place a paper clip in the center of the spinner and put your pencil tip in the center to hold the clip in place.  Using the spinner transparency, draw an unfair and fair spinner.  Ask what is the difference between them.  Using a paper clip and a pencil, spin each spinner twelve times and record the data. Discuss why the results are different. 

Let the students pick a partner and give them a spinner sheet (attached) with two circles and wedges.  The students need to decide how to color a fair and unfair spinner on their sheet.  Have the students predict which color is going to be spun the most.  Have them share their predictions with their partners.  Give them paper clips and have them use each spinner 20 times.  Students should record their results using tally marks. 

Sometimes the experiment doesn’t work.  If a child raises their hands and says their findings aren’t appropriate, have them spin again 20 times. 

Once complete, have some students share their findings.  Teacher will collect spinner sheets and score using the rubric. 

To close this activity, ask the students how they could use probability in their every day life.  Have students respond orally.  Remind them that when they go home and play board games or when they go to the fair and play games, they have to think of the probability.  Finally, let students choose whether they want to display their spinner results in the hallway or post them on the school’s web page. 

Visit the web site http://www.col-ed.org/cur/math/math26.txt for another idea on teaching probability.

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Probability Using Spinners

Color a fair and unfair spinner.  Using a paperclip and a pencil, spin 20 times on each spinner.  Record your results on the tally charts below the spinners.  At the bottom, write about the difference between the two spinners.

What did you discover?  Did you have the same results from both spinners?

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