A student wants to investigate the amount of bacteria on door handles. Bacteria is commonly found on door handles and the amount varies based on the location of the door. The student is interested in studying the amount of bacteria found on the bathroom door handle compared to the kitchen pantry door handle. What must the student do in planning this investigation? Explain how you would you apply the scientific method to this question.

Your answer should include at least five complete sentences.
Be sure to check your grammar and spelling.

usally people use strong or normal microscopes so should use that

Explanation:

Assignment Summary

For this assignment, you will apply what you know about the technological design process to solve an

Earth Science–related problem in your community.

Background Information

Engineers and scientists are problem solvers. They design and make products that help solve problems

such as pollution, erosion, and even climate change. The products they make help keep Earth healthy.

For example, engineers have designed the equipment in water treatment plants to improve the quality of

water used by homes and businesses. This equipment allows water to be reused and reintroduced into

the water cycle without harming the environment or living things on Earth. The technological design

process is useful in addressing large- and small-scale problems.

Materials

 Varies by prototype/model

Assignment Instructions

For this project, you are expected to submit the following:

1. Your Student Guide with completed Student Worksheet

2. Your prototype or model

Step 1: Prepare for the project.

a) Read through the guide before you begin so you know the expectations for this project.

b) If anything is not clear to you, be sure to ask your teacher.

Step 2: Identify a problem or need in your community that can be solved by apply

Explanation:

c) Evaluate the possible solutions against the criteria. Use the table in the Student Worksheet to

evaluate the possible solutions. Add more columns and rows if necessary.

d) Choose the best solution. Highlight the best solution in the table in the Student Worksheet and

explain the tradeoffs you had to make, if any.

Step 4: Implement the solution.

a) Prepare the materials you need to build a prototype/model.

b) Build a prototype/model of the product.

c) Test the prototype/model.

d) Analyze the results of your test. Record your findings in the appropriate space in the Student

Worksheet.

e) If your test shows that your product/model is successful, submit your prototype/model to your

teacher. Be sure to put your name on it. Then, proceed to step 6. If your test is not successful,

continue to step 5.

Step 5: Redesign and retest solution (if necessary).

a) Adjust the design of your prototype as necessary. Draw your redesigned prototype/model in the

space provided in the Student Worksheet.

b) Retest the prototype/model.

c) Analyze the results of your test. Record your findings in the appropriate space in the Student

Worksheet.

d) Submit your prototype/model to your teacher. Be sure to put your name on it.

Step 6: Evaluate your project using this checklist.

If you can check each box below, you are ready to submit your project.

 Did you identify an Earth Science–related problem in your community?

 Did you do related research to help you solve the problem?

 Did you list your sources at the end of the Student Worksheet?

 Did you establish criteria for your solution? Did you list the criteria in order from most important to

least important?

 Did you draw prototypes/models of possible solutions?

 Did you evaluate possible solutions against the criteria?

 Did you choose the best solution? Did you highlight the best solution in the table?

 Did you explain tradeoffs you had to make, if any?

 Did you create a prototype/model of the best solution?

 Did you test your prototype/model? Did you record the results of your test?

 Did you redesign your prototype/model if the original prototype/model did not work the way it was

supposed to?

 Did you test your new prototype/model? Did you record the results of your test?

 Did you complete your Student Worksheet and submit it online?

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.