Posted by David Wetzel
Egg in Bottle Investigation
This is a an investigation into “forces” discrepant event in which students make observations of an event and then explain the science that caused the event.
This simple; however complex, investigation is a great attention getter for learning about forces and atmospheric forces.
May the Force be with You
Materials: (per group)
- One hard boiled egg with shell removed
- One clear plastic or glass bottle that has an opening narrow enough that the egg will not fit through
- One strip of paper about one inch by six inches
Procedures:
- Light the piece of paper with a match and place the paper inside the bottle
- Place the egg in the opening on top of the bottle
- Observe what happens
Expected Observations:
As the paper burns inside the bottle, the bottle will fill with smoke. Shortly thereafter, the students will observe the egg begin to slowly change its shape to fit through the bottle opening as it slides through the opening. Suddenly the egg will fall through the opening and land at the bottom of the bottle.
Questions to Ask Students:
- What did you observe? (Common answer is that the egg was sucked into the bottle.)
- What force or forces caused the egg to enter the bottle? (Common answers include air in the bottle forced the egg inside or gravity pulled the egg inside.)
Science Behind the Discrepant Event
The burning piece of paper heats the molecules of air in the bottle. This causes the molecules of air to move further away from each other. When the flame goes out, the molecules of air in the bottle cool down and move closer together. This is what scientists refer to as a “partial vacuum “. Normally the air outside the bottle would come rushing in to fill the partial vacuum created inside the bottle.
However, the egg is in the way! The “push” or pressure of the air molecules outside the bottle is so great that it literally pushes the egg into the bottle. Gravity causes the egg to fall to the bottom of the bottle.
Discrepant Event Resource
Teaching Science Using Discrepant Events
Posted by David Wetzel
Science Mysteries
Science mysteries provide a natural strategy for integrating critical thinking and problem solving skills in science. These mysteries can be be presented to the students in various manners, although the most engaging technique is through stories. Stories that peak the interest of students through suspense, excitement, and fun offer the best approach.
Science mysteries which focus on content standards, involve use science process skills, and involve the use technology are an ideal method for immersing students in the learning process.
Strategies and Techniques
Using web-based learning centers is good strategy for integrating technology in traditional learning centers. Web-based learning centers allow students to access approved websites for investigating science mysteries to solve a problem and quickly answer questions for students as they develop their own questions.
Using science mysteries also provide the opportunity to integrate reading and writing in science. Writing and presenting solutions to these mysteries can be achieved through he use of Google Docs, which provide the opportunity for collaboration in and outside the classroom.
Resources
These mysteries require students to read, write, use technology, and use science process skills to solve each mystery.
Bottled Water Versus the Environment
Science Mysteries for grades 5 - 12
Posted by David Wetzel
Algebra Problem Solving
Every algebra teacher is bombarded with the same question every year — “What will I ever use this algebra stuff for?”
Well here is a sample algebra problem that you can use to respond to these insidious questions, along with proving to your students that there is no magic or mystery when algebra is used.
The Problem
Step 1 - Write down the year you were born. [P}
Step 2 - Write down a year when a memorable event took place in your life. [Q]
Step 3 - Write down your age as the last day of this year. [Y-P]
Step 4 - Write down the number of years since the memorable event (Step 2) took place. [Y-Q]
Step 5 - Add the 4 numbers obtained in Steps 1 through 4. [P + Q + (Y - P) + (Y - Q) = 2Y]
Every student will have the answer 2Y = 4018 or Y = 2009 (or what ever the current year is when calculating)
How does this work?
P +Q + (Y - P) + ( Y - Q) = P + Q + Y - P + Y - Q (parentheses removed)
= P- P + Q - Q + Y + Y (rearranging the terms)
= 2Y ( P’s and Q’s cancel each other out)
= 4018 (when Y = 2009)
In other words, the number in Step 1 combined with that in Step 3, deleted the number in Step 1, giving the current year, 2009; similarly, the number in Step 2 combined with that in Step 4, deleted the number in Step 2, giving, once again, the current year, 2009.
Therefore, adding all the 4 numbers from Step 1 through Step 4 effectively deleted every number other than twice the current year, 2009, giving the result of 2 x 2009 = 4018!
(Note that most number puzzles undo what has been done, so as to “force” a certain result, as can be easily proved by using deductive logic or by using algebra.)
Resources
Tips for Solving Math Word Problems
Math Problem Solving
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