Complete experiment:
- Before beginning the experiment, record at least two observations of the raw egg in your lab report. Wrap the string around the center of the egg to determine its initial circumference. Measure the string and record the initial circumference in centimeters (cm).
- Gently place the egg in the jar and completely cover the egg with vinegar. Use the lid to seal the jar and note the time. This will be considered the "start time" of the experiment.
- After approximately 24 hours from the start time, carefully remove the egg from the jar of vinegar. If the shell has completely dissolved, exposing the inner membrane, move on to the next step. If not, return the egg to the vinegar until the shell has completely dissolved. Record at least two observations of the egg. Measure and record the circumference of the egg, being sure to measure it in the same way every time you measure circumference.
- Pour out the vinegar and rinse the jar. Then fill the jar about half full of tap water.
- Gently place the egg back into the jar, making sure it is completely covered with water. Use the lid to seal the jar.
- After a total of 48 hours from the start time, carefully remove the egg from the jar of water. Make two observations of the raw egg, and measure and record the circumference.
- Gently place the egg back into the jar, making sure it is completely covered with water. Use the lid to seal the jar.
- After a total of 72 hours from the start time, carefully remove the egg from the jar of water. Make two observations of the raw egg, and measure and record the circumference.
- Describe the results of your experiment or study. Use graphs and charts where appropriate.
Answer and Explanation:
During an investigation, a researcher can study, under controlled conditions, how one of the variables influences the other one. The independent variable can be manipulated by the researcher, while the dependent one can not. The independent variable can show different values that do not depend on another variable. Instead, they directly affect the values of the dependents ones. A hypothesis is a claim of how this relationship works.
The independent and the dependent variables are the two principal factors needed in an experiment.
- Independent variable / Manipulated variable: Refers to all the variables in an experiment that provoke a response in another variable. This variable is modified during the experiment to analyze how another variable responds to it. The researcher wants to study how the changes in these variables affect the dependent variable. The researcher can change these variables to see what changes it implies in an object, process, trait, or anything that depends on them. Usually, the independent variable is represented by the X letter. In the exposed example, the researcher manipulates the time that the egg is submerged in water. Time spent in the water is the independent variable
- Dependent variable / Responding variable: Its response depends on any change in the independent variable. The dependent variable is the one that is being investigated, studied, and measured. It represents a quantity of something which value depends on how the independent variable is modified. It is usually identified by the letter Y. A change in the dependent variable might be proportional or inversely proportional to the change in the manipulated variable. In the exposed example, the dependent variable is the egg circumference.
The egg gets bigger changing its circumference as it spends more time submerged in water. The longer time it is submerged, the bigger it gets.
- Constants / Controlled variables: Refers to those variables in an experiment that are controlled and have no influence on the results. These variables do not affect the change in the dependent variable values. In the exposed example the use of the lid to seal the jar and the amount and concentration of vinegar might be considered as a controlled variable. These elements are used but do not provoke any change in the size of the egg.
8
0