Modeling with Water Olympics

-Modeling with Water Olympics Warm-up Agenda -WarmUp -Modeling with Water Olympics -Intro Salt Lab What type of bond keeps water molecules together and creates surface tension? Is oil hydrophobic or hydrophilic? Name the intramolecular force in water.

Lab safety revisited I understand the lab safety rules discussed and agree to follow them in Mrs. Mullins’s Science class. I understand that I will earn a zero, not allowed in lab and will be given an alternative assignment on lab days if any of these rules are broken.

Modeling Water Olympics Define the vocabulary words on the right hand side of your paper please 

Amazing Water Race: Station 1 Water is a polar substance. Do you think the wax paper is a polar or nonpolar surface? Why? Wax paper is nonpolar since the water was not absorbed by the paper and rolls right off Explain what is happening during the “race” in terms of cohesion and adhesion. The water molecule stays together because of cohesion Weak attractive force between water and wax paper (weak adhesion) so that’s why it stays in larger water droplet

Were you able to do something to help “stretch” the water further Were you able to do something to help “stretch” the water further? If so, explain how you did it. If you add soap to the wax paper you would be able to break the surface tension and stretch the water further

Fold and Float: Station 2 What causes something to sink? A high density (when molecules are more compact than the other substance) According to your answer, should aluminum sink or float? Aluminum should sink since it has a higher density than water List two examples of where surface tension is important in the real world? Water in our cells supports our cell membranes, without surface tension our cells would collapse and we would die With surface tension, pollen and dust particles float on top of bodies of water. With no surface tension, these particles would sink and ruin the ecosystem

Color me Crazy: Station 3 What property of water allows for this phenomenon to happen (water being “pulled” up the paper towel)? Capillary Action

Bubble Rings: Station 4 What properties of water do you think allowed you to blow the bubble? Surface tension What does surface tension have to do with bubbles? When you blow air into soapy water, the air stretches the surface. The surface tension in this stretchy layer captures the air and pulls the soapy water into the shape of a sphere

Looney Ballooney: Station 5 What did you do to the balloon on a molecular level to produce the observed results? The electrons in the paper towel went to the balloon when rubbed causing a negative charge in the balloon

Clips-n-Dip: Station 6 What would heating the water do? Paper clip sinks immediately What about cooling the water? Paper clip will float more easily Draw what you think the water molecules on the surface look like during this activity.

Stop on a Dime: Station 7 What properties allowed you to “stack” water drops on a dime? Water stays together in drop thanks to cohesion and surface tension Water stays on top of penny because of adhesion What would have made this work better? If water was cold What would have made it not work as well? If soap was added

Water in a Cup: Station 8 Explain why you believe this happened. Surface tension and adhesion The water molecules stick together through surface tension Water molecules are attracted to the paper, adhering to it, while continuing to keep the surface tension with the other water molecules