## Hover Above the Earth

### Dawn GottSanta Rosa District Schools

#### Description

Students build a balloon hovercraft, take direct measurements, answer critical questions, and make calculations using the data gathered in order to realize the concept of acceleration as a change in velocity.

#### Objectives

Selects and uses direct (measured) or indirect (not measured) methods of measurement as appropriate.

The student knows that any change in velocity is an acceleration.

#### Materials

-20 cm x 20 cm cardboard square, one per group
-Pencils
-Pattern for a circle or a compass
-Razor knife, to be used by the teacher only
-Self-adhesive shelf paper, e.g. contact paper
-Scissors, one per group
-10” or 11” round balloon, one per group
-Marker, any color, one per group
-Scale (in kg increments), e.g. triple beam balance
-White glue
-Squirt bottle cap, e.g. dish soap bottle cap
-Centimeter ruler, one per group
-Timing device, e.g. stopwatch or watch with a second hand
-Tape, masking tape or duct tape
-Copy of Hover Above the Earth Activity, Data, and Analysis Sheets, one per student (See Associated File)
-Smooth floor, e.g. tile floor
-Meter stick

#### Preparations

*NOTE: It is advisable for the teacher to make a hovercraft in order to troubleshoot problems that might arise and provide a model for the students to view.

1. Two or three weeks prior to the 1st day of the activity, start having your students bring in their squirt bottlecaps, or start collecting them yourself to assure you have an ample supply for the activity. This activity is easy enough to set up where each student makes their own hovercraft, if you have enough supplies, or 1 hovercraft per 2 students (this is the best allocation of resources). The bottle caps should have a pull-up spout, such as those found on dishwashing detergent bottles or sport drink bottles.
2. The day before the data gathering portion of the activity, you should “stake out” an area that has a smooth floor, such as the cafeteria or hallway. You need one track, but 5 or 6 tracks make the activity move faster (it depends on how many groups you have). Using the tape, mark off a 1 meter by 2 meter track. Mark off the 2 meter track(s) in centimeter increments, for easier measuring.
3. Gather all materials at a central location so the students have easy access to them.
4. Make copies of the following, one per student (copy the sheets front and back to save paper).
a. Hover Above the Earth Activity Sheet (See Associated File)
b. Hover Above the Earth Data Sheet (See Associated File)
c. Hover Above the Earth Analysis Sheet (See Associated File)

#### Procedures

*NOTE: It is advisable for the teacher to make a hovercraft in order to troubleshoot problems that might arise and provide a model for the students to view.

DAY 1
1. Have your hovercraft ready and cause it to scoot across a desk as a great way to get the attention of the students. Ask students what they know about hovercrafts.

2. Ask the students to define velocity and acceleration. After several students have attempted the definitions, review with them the correct definitions and the concept of acceleration as a change in velocity. Ask the students what factors may hinder an object's velocity/acceleration, such as friction.

3. Review with the students how to derive answers using algebraic expressions (this is a standard which should already be mastered, MA.A.3.4.3). Ask students what formulas are used to calculate velocity and acceleration. (The formulas needed for this activity are in the associated file on the Hover Above the Earth Data Sheet.)

4. Tell the students to read the procedure of the activity prior to beginning. (See Hover Above the Earth Activity Sheet in Associated File) Review the expectations of the activity with the students.

5. Distribute the Hover Above the Earth Activity, Data, and Analysis Sheets. (See Associated File) Have the students obtain the materials needed for this activity at a central location, such as the demonstration table or lab cart.

6. Tell the students to follow the directions on the Activity Sheet to construct their hovercrafts. Be prepared to cut the cardboard for any students who ask for this to be done using the razor knife. Do not let any students use the razor knife but explain that the cutting can be accomplished using scissors.

7. When the hovercrafts are completed, tell the students to mark their hovercrafts with an identifying mark and place them on a cart or table for use during Day 2.

DAY 2
8. Escort your class to the track or tracks that you marked during the preparation stages. Tell the students to employ their hovercrafts, reminding them to take careful readings and measurements and record the readings and measurements on their Data Sheet.

9. Escort the class back to the classroom when all trials are completed. Tell the students to spend the remainder of the class time using their data to accomplish the calculations.

10. Tell the students to submit their finished worksheets at the end of class for assessment purposes.

#### Assessments

The Data and Analysis Sheets (See Associated File) are formative instruments used to assess the students' abilities to:
1. Measure quantitative aspects about their hovercraft.
2. Calculate a volume and a surface area.
3. Determine the acceleration of the hovercraft by direct calculations.
4. Determine the acceleration of a hovercraft by proposed figures.

NOTE: The answers from the Analysis Sheet should be determined by the data collected and recorded on the Data Sheet. This means that answers on the Analysis Sheet could and probably will be different depending on each student’s data.

#### Attached Files

This file contains the Hover Above the Earth Activity, Data, and Analysis Sheets.     File Extension: pdf