Eggscellent Egg Catch
A) Objective: To construct an "egg catch" to
successfully catch an egg dropped from about 2 m.
B) Time: 45 minutes
C) Materials:
- List materials:
- Scrap paper (8 sheets per group)
- Masking tape
- Eggs
- Materials found at: Donated or scrap
- Cost per student: $0.25 (if they break an egg each!)
D) Theory: Energy is all around us and exists in many forms. It is never destroyed, but simply takes on different forms. Some examples of the forms energy can be displayed in are: kinetic, potential, elastic, heat and sound. Kinetic energy is the energy an object possesses when it is moving and has velocity. Potential energy is the energy stored in an object. The potential energy of an object increases when its height from the ground is increased. Elastic energy is the energy stored in a spring which is compressed or stretched from its original length.
In the case of the egg catch, the egg initially has zero kinetic energy because it is not moving, so all of its energy is stored. However, when the egg reaches the ground, it has a height and potential energy of zero. Since energy is always conserved all the initial potential energy has been converted to kinetic.
When the egg is at the height of the door frame it will have a potential energy of:
where:
When the egg falls to the ground the potential energy is transferred to kinetic energy, which can be found using the equation:
where:
Egg Catcher
The children should take into consideration ways to convert
the kinetic energy into other forms to save the egg from breaking.
Converting the kinetic energy into heat, sound and elastic energy
should be incorporated into their egg catchers. The structure
should also ensure the catcher has side supports so the egg does
not bounce out. Emphasis should also be placed on t he challenge
of working in groups! The best discoveries are made by teams!
D) Procedure:
- Arrange the children into groups of three or more and give them time to design their egg catchers. The egg catchers must be free standing and cannot be held up.
- Practicing may be done with other egg shaped objects suck as an eraser, liquid paper, etc.
- When all the catchers have been tested (with the pseudo-egg), display the catchers on the demo table (to keep people from fiddling and to speed up testing). Randomly choose the catchers to test.
- Stand on a chair to drop real eggs. Use an "egg tube", a roll of paper tubes, to aim the egg.
- A cracked egg is a broken egg. If an egg bounces off the egg catcher and then breaks, or if the egg catcher falls over and the egg breaks, it will be considered an unsuccessful attempt.
- A wrap-up discussion should be held, emphasizing the most
successful designs and their features!!
E) Real Life Examples: Stunt people and gymnasts use mats and other items to soften the impact onto the ground.
