What do you notice? What do you wonder?

1. Altitude is the vertical distance from sea level. Here are the altitudes of 10 planes.

   plane	altitude (feet)
   WN11	35,625
   SK51	28,999
   VT35	15,450
   BQ64	36,000
   AL16	31,000
   AB25	35,175
   CL48	16,600
   WN90	30,775
   NM44	30,245

   

    

   Which planes are flying at about 30,000 feet? Explain or show your reasoning.

2. Planes flying over the same area need to stay at least 1,000 feet apart in altitude.

   Mai says that one way to tell if planes are too close is to round each plane's altitude to the nearest thousand. Do you agree that this is a reliable strategy?

   In the last column, round each altitude to the nearest thousand. Use the rounded values to explain why or why not.

Use the altitude data table from earlier for the following problems.

1. Look at the column showing exact altitudes.

   1. Find 2 or more numbers that are less than 1,000 feet apart. Mark them with a circle or a color.
   2. Find another pair of numbers that are less than 1,000 feet apart. Mark them with a square or a different color.
   3. Based on what you just did, which planes are too close to one another?

   

2. Repeat what you just did with the rounded numbers in the last column. Use these numbers to find which planes are too close to one another.

3. Which set of altitude data should air traffic controllers use to keep airplanes safe while in the air? Explain your reasoning.
4. Are there better ways to round these altitudes, or should you not round at all? Explain or show your reasoning.

In some countries, cell phone use is allowed on a flight only when the plane is at a certain altitude, usually around 40,000 feet.

Here are 6 planes and their altitudes.