Introduce this activity by reviewing previous lessons where students have had the chance to work with a variety of mixtures. Then show the Science Bob website videos about Making Slime to the class. After watching the video talk about the different ways that slime can be made and how it involves making observations and testing.
2 Direct Instruction
Demonstrate to the students what happens when you mix cornstarch and water. Have them make observations about the change in properties after the substances were mixed. Walk around and let them try to punch or poke the substance. Show them what happens when pressure is not applied to the substance. Use Science News for Kids to read the article called "Walking on Water". Discuss the implications of investigating specific mixtures and substances. Let students know that different materials and substances can be used for different purposes. Ask students to turn and talk with another student and come up with ways that this specific mixture could be used. Have the students share their ideas with the whole class. At this point introduce or review the job of an engineer with the class (To design, test, modify, improve upon things to solve a problem). Tell them that they will be using their knowedge about mixtures and their skills of observation to engineer a product.
3 Guided Practice
Students will need to form teams of 2 or 3 people. Present the following challenge to the class:
You have been asked to design a sticky substance that will be used to display a variety of paper types.
Tell teams that they will need to use their knowledge about substances & mixtures along with the available materials to engineer a substance that will meet this need. Let them know that they will be asked to record all of their work so that they can "pitch" their new product to the company. Remind them that they must record exact amounts and ratios of all ingredients and the specific steps needed to manufacture their subtance. If possible they should be given the opportunity to take digital pictures of their work to use in their presentations.
Give them the following materials and constraints:
-Containers for mixing
-Spoons or tongue depressors for stirring
-Measuring cups, spoons
-A variety of paper types for testing (i.e. copy paper, cardboard, cardstock, newspaper)
-Display board or large piece of cardboard
-Recording Data Sheet or Notebook
(any other material you think would be appropriate or useful for this challenge)
--The sticky substance you create must enable all the paper types to stick to the display surface after drying.(Should stil stick after it is left overnight)
-The sticky substance should not distort the image or the original condition of the paper on display.
-The sticky substance should not be seen or noticed under the paper on display.
4 Independent Practice
Students will work in teams and use Prezi to make a commercial for their new sticky substance. Each group will need to name their product, design a logo, and try to "sell" (convince) the company that their product is the best for its intended purpose. Let students know that they will be presenting their commercial to a specific audience when they are finished. (It could be arranged beforehand to have students present their commercials to another classroom or audience of adults.)
Students will Prezi to share their comercials with the class or other audience. Have the audience select the product that they think will be best. A discussion can be had after the winner is announced about the ways in which their products could be improved or modified.