# Elapsed Time

Shodor > Interactivate > Lessons > Elapsed Time

### Abstract

In this lesson, students will learn about elapsed time and how to find the elapsed time given the starting and ending time.

### Objectives

Upon completion of this lesson, students will:

• understand the concept of elapsed time
• be able to calculate elapsed time given the starting and ending time

### Student Prerequisites

• Arithmetic: Students must be able to:
• complete simple addition
• Technological: Students must be able to:
• perform basic mouse manipulations such as point, click and drag
• use a browser for experimenting with the activities

### Teacher Preparation

Students will need:

• paper and pencil

### Key Terms

 addition The operation, or process, of calculating the sum of two numbers or quantities elapsed time A period of time that has passed, usually between a given starting time and ending time

### Lesson Outline

1. Focus and Review

Open the lesson with this question, replacing times to make it more authentic:

• We started math at 10 a.m. It is now 11 a.m. How long have we been doing math?
• What do we call this time?

2. Objectives

Let the students know what they will be doing and learning today. Say something like this:

• Today, class, we are going to learn what elapsed time is and how to calculate it.
• We are going to use the computers to do this but please do not turn your computers on until I ask you to. I want to show you a little about this activity first.

3. Teacher Input

• Lead the students in a discussion about elapsed time.

4. Guided Practice

• Have the students draw starting and ending times on their Elapsed Time Record Sheet. Then instruct them to calculate the elapsed time.
• Open your browser to the Elapsed Time applet. Explain to the students how to work the applet.

5. Independent Practice

• Have students answer 10 problems on their own.
• Have the students answer the Exploration Questions while working with the applet.

6. Closure

• Discuss as a class what the students discovered while answering the exploration questions.

### Alternate Outline

If there is only one computer, this lesson can be modified in the following ways:

• The teacher can prepare problems by given students various starting and ending times. The students can then discuss methods for finding elapsed time.
• Students who need additional help can use the applet after completing the problems on paper.  