from Come Fly With Me – Exploring Science through aviation and aerospace concepts.
GROUP SIZE: Large Group
TIME: 2-45 minute periods
TYPE OF ACTIVITY: Student Investigation
TEACHING STRATEGY: Expository Guided Discovery
CONCEPTS: Calorie Energy/Mass Time and Distance
SKILLS: Reading and Interpreting Data Interpolating Data Using a Stopwatch
Objective: To provide students with an opportunity to determine how long it would take them to run to the moon and to relate that time to the energy requirements for a human and for a spacecraft making the same trip.
Materials: Stopwatch; meter tape; activity sheet provided; optional – a loaf of white bread).
Teacher Background Information: The following activity is included to provide students with an opportunity to use some large numbers in determining how long it would take them to run to the Moon. In addition, information related to the energy requirements is furnished so that students can get some idea how much energy would be required for them to make such a voyage. Following the first part of the lesson, the students are asked to relate their own speed with that of a Saturn Rocket and to compute the energy requirements of the rocket for the same voyage.
Hand out the activity sheet and ask that the students read the top and do Step 1 together with you. Together, set up an area outside which is 50 meters long and do Step II. After each student has recorded their time across the 50 meter run, have them use the graph on their activity sheet to compute the number of days it would take to run to the Moon.
Now, do part 2 of the activity sheet together. Do an example on the board so that everyone knows how to calculate the first question. Have them compute how many hamburgers it would take to fuel them for the run. Talk over the next two questions with them and ask them to determine what additional information they may need to answer.
The following day,have them compute the answers to questions 1 and 2 in Step IV using the data they have collected over night. First, determine the number of slices of bread in the loaf of sandwich bread you have brought to class. (The students may have been asked to find this out overnight.) Second, determine the weight of each slice by dividing the number of slices into the weight of the loaf. Third, Multiply the weight of each slice by the number of slices it would take to run to the moon. Fourth, divide this weight by 1000 to yield how many kilograms of bread it would take. Fifth, dividing the student’s weight (mass) into the total weight of the bread in their “get to the Moon loaf” will yield the number of kilograms of bread to get one kilogram of kid to the moon.
Now, carry the exercise one step further. Explain to the students that our largest launch vehicle, Saturn V, can lift about 45,000 kg into orbit. This is the vehicle that took us to the Moon. It is 111 meters tall and, when fueled, has a mass of about 3,000,000 kg. The fuel alone has a mass of 2,700,705 kilograms. Dividing the payload of 45,000 kg into the total propellant mass yields a ratio of about 60 kg of fuel to lift 1 kg of payload into orbit. How does this compare with the students calculations on the kilograms of bread to lift one kilogram of student into orbit?
Extension: Have the students calculate their travel time and energy requirements to other planets in the solar system. See the activity, “How Long ‘Till we Get There?” Discuss limiting factors on the speed of spacecraft. What might be some things that would slow a space vehicle down?
What might be some alternative energy forms to be used in space? Huge sails pushed by light have been suggested. What might other sources be? What might be the consequences of the use of nuclear fuel?
Adapted from educational materials available from NASA Spacemobile program 120
Activity sheet for “A RUN TO THE MOON”
This activity will give you the chance to determine how long it would take you to run to the Moon. In addition, you will determine how much energy it would take you to make the run. Have fun !!
Step I: Estimate how many days, you think it would take you to run to the Moon if the average distance to the Moon is 386,000 kilometers _______ days.
Step II: Determine the time it takes you to run 50 meters. Measure the time with a stop watch and record the time _______ seconds.
Step III: Use the chart provided to determine how many days it wou1d take you to run the distance to the Moon. days.
Activity sheet for “A Run To The Moon”
Energy requirements for a long run to the moon:
A calorie, remember, is defined as the amount of energy required to heat one gram of water one degree Celsius. Remember also, that the food Calorie is really a kilocalorie (1000 calories, denoted with a capital “C”). The Calorie content of food is an important value to know since different foods provide different amounts of Calories and therefore, provide different amounts of energy to the user for different tasks. If an individual takes in more Calories than needed the excess is stored as fat.
A slice of bread contains about eighty Calories. Knowing this value, it is possible to determine the number of Calories and also the number of slices of bread it would take to fuel you for your run to the Moon.
As an example, it took a person running 50 meters every 15 seconds, 1342 days to travel the distance to the Moon. Multiply the days by 24 hours to get the number of hours to the Moon. If the average person burns about 864 Calories per hour while jogging, you can determine the Calories needed to run to the Moon by multiplying 864 times the number of hours to the Moon.
- 1342 x 24 hours/day x 864 Calories/hour = 27,827,712 Calories to the Moon
Divide the total number of Calories by 80 (Calories in a slice of bread) to get the number of slices of bread you would have to take with you to eat along the way.
- 27,827,712 Calories / 80 Calories/slice = 347,846 slices
- Question 1. How many slices of bread must you eat to make it to the Moon?
- Question 2. How high would a loaf of bread with this many slices be (clue: if a slice were 1.5cm thick, the loaf in the example above would be 1.5cm x 347,846 = 434,808cm high. About 4.3 kilometers – 2.7 miles high)
- Question: If a double cheeseburger with lettuce, pickles, sauce, and tomato has 500 Calories, how many burgers would it take you to get to the Moon?
- Question : If you stacked those burgers up, how high would the stack be? How much would all this cost?
Next time someone wants to send you to the Moon, tell them it‘s going to cost a “lot of bread” baby!!!