Learning Information

• ToL Learner Level:
  • Beginner; Intermediate; Advanced
• Target Grade/Age Level:
  • All Grade/Age levels.
• Learning Objective(s). Learners will:
  • Choose an activity that will culminate in participation in an interactive museum exhibit about life at the water's surface.
• Additional Treehouse Type:
  • Investigation

Introduction

The themes addressed by this exhibit are an investigation of the different species capable of living on the surface of water, the special adaptations that make this lifestyle possible, how these organisms move, mate, find food, and the footprint these organisms leave in their environment. In addition, the the properties of water that are mechanically advantageous will be explored. These themes will be addressed in a cohesive exhibit containing various methods to communicate the material and will be appropriate for all ages. The exhibit will present information to achieve certain goals. These goals include:

• encouraging curiosity, questioning, and exploration
• informing and educating
• enhancing a sense of personal achievement through learning
• respecting individual interests, background, and abilities
• promote life-long learning and active citizenship

This exhibit activity could be incorporated into classroom use by assigning acitivities to groups or individuals over a short period, or requiring groups to complete all activities over a longer time period. These lessons could easily be altered to suit any age student.

Project

Activity 1: Contruct a model museum exhibit

This exhibit will be constructed in the form of a bug with four legs and a body functioning as museum space. There will be two legs and a head that will be non-functional but aesthetically enhancing. This exhibit will integrate use of technology, art, writing, and simple scientific experiments to convey complex ideas in a simple, understandable manner.

 Your task is to design a museum space where material can be presented clearly. The space must also allow for the other activities in the museum exhibit and a species pool. Construct a model of the museum exhibit. Make sure to point out where you placed the different parts of the exhibit and give reasons why this layout will work.

Activity 2: Designing a species pool and researching species adaptations

Patrons who enter the Life at the Water’s Surface exhibit will be connected to the species and phenomena explored and explained by viewing the species pool. This pool will feature the four unique habitats for the four species featured in the exhibit. The pool will host one organism in each of its four divisions: the marine water strider, the water scorpion, mosquito larvae, and the whirligig beetle.

Your task is to design a species pool by researching the habitats of the four resident organisms. Each of the four divisions of the pool will feature one of the organisms and must be deisgned with their individual needs in mind. The pool should also incoporate the use of technology that would allow museum patrons to make a connection with the resident organisms and peak their interest. Make sure to include this pool in your model and explain the special feature of each habitat and your use of technology to enhance the exhibit.

Your second task in this activity is to research a special adaptation that each resident organism has that allows them to live and thrive at the water's surface. You should make posters highlighting these adaptations and be prepared to present these to the class. The adaptations you should research for each organism are:

-The water strider display will highlight the long hairs seen on the water strider’s legs and explain how these structures allow for the water strider to jump into the air from the surface of the water.

- The display for the whirligig beetle will feature the beetle’s eyes that allow it to see above and below water.

-The mosquito larvae adaptation display will highlight the siphon of the larvae, which allow it to breathe while suspended under the water.

-The water scorpion’s adaptation display will feature their egg’s respiratory horns, their siphon, and their ability to trap oxygen bubbles beneath their wings to breathe underwater

Activity 3: Surface Tension and Capillary Action

To investigate capillary action you will carry out a demostration for your class using a model of a tree with pool of water at the bottom. You will ask your classmates to select the capillary tube able to bring the water from the pool to the top of the tree. This is a hands-on illustration of adhesive and cohesive forces at work and will require some additional research into the properties of water that make this possible. The correct capillary tube maximizes the adhesive force drawing water up the tube by having a small radius and minimizes the distance the water has to travel by taking the most direct route to the top of the tree.

Your task is to prepare this demonstration by gathering various size tubes of differing lengths and radii. Be prepared to explain the results of this demonstration to the class. Make sure to include the properties you have researched about water that make this phenomenon possible.

To investigate surface tension, you will carry out another demonstration for your class using a tub of water a paperclips. You will show your classmates that a paperclip placed gently on the durface of the water will be supported while one dropped from a distance above the pool will sink to the bottom.

Your taks is to prepare this demonstration by gathering paperclips and a tub of water. Be prepared to explain how the water is able to support the weight of the paperclip using your knowledge of water properties and surface tension.

Activity 4: Insect Locomotion

Many aquatic insects have long, slender legs with feet that act as paddles, as well as streamlined bodies. The combination of this leg shape and a light-weight body are integral to an insect’s ability to walk on water. The water strider, for example, has three pairs of legs, as does any other insect. Its legs, however, each have a specific function that aids in water surface movement. The front legs function to support the insect, while the middle legs are used as paddles, and the hind legs are used for steering. Many aquatic insects have microscopic, water-repellant hairs on their legs and bodies, as well as waxy exteriors. The hairs function to prevent water from diffusing into the insect’s body, to repel water molecules so the insect does not become trapped by the surface tension, and to increase the surface area of the feet.

The small mass and size of the insect’s body is integral to its ability to walk on water. If an insect has a mass of 10mg, a minimum of 2mm per leg must come in contact with the water surface. The upward force from the water is proportional to the perimeter of contact between the feet and the water surface. The mass of the body that needs to be supported increases proportionally to the cube of the body length, so large water striders need longer legs to ensure they can stand on water. If the relationship between the insect’s size and the amount of contact it has with the water is not correct, the surface tension of the water will break.

Your task is to research the special adaptations water surface dweilling organisms have and prepare a presentation on your findings. You can also calculate how big a human's feet would have to be to enable them to stand on water using the information above. Assume the person in 125lbs (1pound = 453.59grams) and remember we have two feet. Explain your results to the class.

Activity 5: Exploring Vortices

Vortices themselves are technically demanding to learn about; although it’s feasible to understand that they are generally any sort of fluid flow of streamlining around a center, like a tornado in water, in this situation it might be best to leave out more detailed assessments of the vortices such as their Reynolds’ Numbers or momentum figures. The velocity and momentum of the vortices are both nearly the same as the velocity and momentum of the water striders themselves, which is evidence that they are responsible for the water strider’s forward propulsion.  The fragile vortices disintegrate at velocities below those large enough quickly, their power dissolves too rapidly as their pace increases, and isn’t enough to make them move forward fast enough. This activity generally presents images of the vortices and explanations of their role in movement.

Your task is to research vortices and their role in the ability of water strider's to move around on the surface of the water. Your can also demonstrate vortices to your class by preparing marble painintgs. For this activity you will need paint, marbles, paper, and a wooden frame. Place your paper at the bottom of the frame, add a squirt of paint to the center of the paper and then mix the paint around by adding marbles to the frame and shaking the frame in circles. This technique should produce images of vortices that can aide in your description of them to the class.