Final answer:
Cross-contamination can introduce unwanted variables or contaminants into samples, leading to inaccurate or unreliable results in an experiment. Sterile equipment and proper cleaning protocols are necessary to prevent cross-contamination.
Step-by-step explanation:
Cross-contamination can ruin the results of an experiment because it introduces unwanted variables or contaminants into the samples being tested. In scientific experiments, it is important to control variables and ensure that only the intended factors are influencing the outcome. When cross-contamination occurs, it can introduce bacteria or other substances from one sample to another, leading to inaccurate or unreliable results.
For example, in a microbiology experiment testing the effectiveness of disinfectants on different types of bacteria, cross-contamination could occur if the same tools, such as pipettes or petri dishes, are used for different samples without proper sterilization in between. This would lead to the unintended transfer of bacteria and compromise the validity of the experiment.
To prevent cross-contamination, researchers should use sterile equipment, follow proper cleaning and sterilization protocols, and separate samples to avoid any potential contact between them.