London dispersion forces are a type of van der Waals forces, which are weak intermolecular attractions between atoms or molecules. They arise due to the temporary polarization of electron clouds in atoms or nonpolar molecules. These forces are present in all molecules but are particularly significant in nonpolar molecules. Since water is a polar solvent, it has strong hydrogen bonds that are not compatible with the weak, transient London dispersion forces found in nonpolar substances. Therefore, substances that primarily exhibit London dispersion forces are not soluble in water because there is a mismatch in polarity; water cannot effectively surround and solubilize molecules held together by these weak forces. Polar and ionic substances, which can interact more favorably with water's hydrogen bonds, are generally soluble in water. In contrast, nonpolar substances that rely on London dispersion forces for intermolecular interactions tend to be insoluble in water, aligning with the principle of "like dissolves like."

Using a 3-way concentrate wetting agent involves diluting the concentrate with water before application. This agent is designed to improve water penetration, distribution, and retention in soil, beneficial for plant health and water use efficiency. First, read the manufacturer's instructions for the correct dilution ratio, as it can vary depending on the specific product and application needs. Typically, mixing is done in a sprayer or watering can. Apply the diluted mixture evenly across the soil or substrate, ensuring thorough coverage. Avoid application during the hottest part of the day to minimize evaporation. For best results, use during planting or when watering plants, as it helps in distributing water evenly and deeply to the roots.

The cost comparison between 3D printing and injection molding hinges largely on the scale of production and the complexity of the design. 3D printing, or additive manufacturing, excels in creating complex, bespoke, or small-batch items cost-effectively, without the need for expensive mold creation. This makes it ideal for prototypes, custom parts, or limited production runs. However, as the quantity increases, the initial high cost of creating molds for injection molding becomes diluted across many units, turning it into a more economically viable option for mass production. Injection molding offers faster production times per unit and decreases the cost per part significantly for large volumes. However, any design changes require the creation of new molds, adding cost and time. In summary, 3D printing is generally more cost-effective for small quantities or complex designs, while injection molding is more economical at large volumes.