7th grade Water  Resources

In 7th grade science we are studying resources and human use/waste. To understand how to improve resources, we need to understand the properties of the matter. In our class, water is the resource and the matter we are exploring. Water is a polar molecule, which means the molecules have positive and negative charges that attract other matter. The polarity of water allows water to stick to other water molecules by cohesion  and stick to surfaces by adhesion. The cohesion and adhesion combined create surface tension. Surface tension is how water 'beads' up on a surface; why your overfilled milk glass doesn't spill, and why a graduated cylinder has a meniscus. We can use this polarity to clean water and use water more efficiently to clean for us.