## Construction and Use of an Accelerometer

### Lisa LocklinSanta Rosa District Schools

#### Description

What is acceleration? The students investigate the concept of acceleration by building and using an accelerometer.

#### Objectives

The student knows that speed, velocity, and acceleration can be calculated, estimated, and defined.

The student extends and refines use of systematic, scientific processes to develop and test hypotheses.

#### Materials

One of each for each lab group:
-One jar with lid (pickle or mayonnaise works well)
-String
-Platted washer or lead sinker or large machine nut or hooked mass
-Ruler
-Stopwatch
-Copies of pages in the associated file
-Meter stick
-Chalk (optional)

#### Preparations

1. Discuss speed, velocity, and acceleration before this lesson.
2. Make sure students are familiar with the acceleration formula.
3. Gather all materials and make copies of the associated files. One copy per group of the lab procedures and the lab questionnaire is needed, and make one copy per person of the checklist.
4. Conduct a review of the lab and the concepts covered in the lab with the students the following day.

#### Procedures

1. Gather all materials and have copies of the associated files before class. One questionnaire and one lab procedure sheet is needed for each group, and make one lab checklist for each person.

2. Briefly, review the concepts of motion, speed, velocity, and acceleration with the students before the lab activity.

3. Instruct students in completion of the lab questionnaire and lab checklist.

4. Divide students into groups for lab. I prefer having lab partners for this lab (groups of two).

5. Have students follow this procedure:
A. Students need to collect lab materials and copies.

B. Cut the string so it is slightly shorter than the height of the jar.

C. Tie the washer to the string.

D. Use the ruler to measure, mark, and find the center of the lid.

E. Attach the free end of the string to the center of the bottom of the lid using tape.

F. Completely fill the jar with water.

G. Place the lid with the washer on the jar. Record the position of the washer. Use the marker to mark the original position of the washer on the jar.

The following predictions should be made before beginning the walking portion of the lab:
H. Make a prediction of what will happen to the washer as you accelerate. Record on the back of the questionnaire.

I. Make a prediction of what will happen to the washer as you are walking at a constant speed. Record on the back of the questionnaire.

J. Make a prediction of what will happen to the washer when you stop. Record on the back of the questionnaire.

One lab partner should record while the other partner walks.
K. Holding the jar steady, start walking. Record the position of the washer as you accelerate (mark the position with the marker on the jar), as you walk at a constant speed (mark the position with the marker), and when you stop (mark the position with the marker). Record the time required for the entire process.

L. Measure a 1-meter circle on the floor. Mark with chalk.

M. Walk in a circle 1-meter in diameter at a constant speed. Record the washer positions (with the marker). Record the time required for the entire process.

N. Complete the lab questionnaire.

O. Clean up your lab area.

P. Complete the checklist on your lab partner.

#### Assessments

Student can describe motion of an object, direction of motion, and speed.
Student can estimate and calculate speed and acceleration.
Student can use scientific processes to develop a hypothesis and test a hypothesis.

Use the attached checklist for students to evaluate each other in groups.

Use the attached lab sheet questionnaire.

Check for accurate use of lab materials, following of lab safety rules, following of lab procedures, and understanding of concepts.

#### Attached Files

This 4-page file contains the lab checklist, questionnaire, procedures, and answer key.     File Extension: pdf