Power of a Student Name______

1. Make a hypothesis: What is your power rating in horsepower? Do you think you are as powerful as one horse? … Two horses?

2. Measure the following from walking / running up the flight of stairs…

Time to go up the stairs, t = ______s Total height stairs, h = ______m

3. Calculate your average power rating, as measured in Watts (J/s) while walking or running up stairs. Show your calculations below. Walk or run up the stairs at least twice to get an average.

4. Convert your power rating calculated above from Watts (J/s) to horse power. 1hp = 746W or J/s.

How many Calories do you really NEED?

Climbing stairs is only one activity in which you use the energy stored in your body during the day. This stored energy comes from the food you eat. In fact most of the energy from the food you eat goes to maintain your internal body functions, like keeping your internal body temperature at 98°F or 37°C.

The energy from food you eat is measured in units of Calories, as described on nutrition labels. One Calorie is equal to 4180 joules or 4.18kJ. The number of Calories each day needed to maintain your internal body functions can be found using one of the following equations…

English B asal M etabolic R ate Formula

Women: B.M.R. = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years ) Men: B.M.R. = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) - ( 6.8 x age in year )

5. According to the preceding paragraph and BMR formula, what is the estimated number of Calories your body needs to maintain your internal body functions? This is the minimum number of calories you need each day.

Modified from Teaching about Energy by John Roeder How many EXTRA Calories do you need?

6. Enter the number of minutes on average each day you perform each activity, and then calculate the number of additional Calories used for each activity by multiplying the #Cal/min by the number of entered minutes, and then calculate the total number of additional Calories used during the day by adding up the Calories. Different values for Calories burned for each minute are provided for males and females.

*Enter the information on the table on the back side of the page* Activity Power (Cal/min) Power Time (min) Energy(Cal) (males) (Cal/min)(females) Standing - talking 1 1 Sitting- driving, 1 1 reading, studying, etc… Listening to music 0 0 or watching TV Walking, normal 3 2 rate Walking up stairs 4.3 3.4 Walking, briskly 5 4 Running, moderate 9 7 speed Playing the Wii 1.5 1.5 Riding in a car or 0 0 truck Eating (sitting) 1 1 Hairstyling 2 1

(Add the last column on the right to get…) Additional Calories Used = ______Cal

7. What is the total number of calories you need each day (add the amount of calories from question 5 and 6)?

Practice Problems

8. How does the power or rate of using energy (Calories/minute) to climb stairs in the table above compare with the value you calculated in step 2 on the 1st page? In order to make the comparison first convert the value from the table from calories/minute to joules / second. (4.3 calories/min = 300 J/s = 0.4hp) If they are considerably Modified from Teaching about Energy by John Roeder different explain why.

9. One 12 ounce can of Mountain Dew is 170 Calories or 710,600 Joules of energy. If your body does not require the additional energy from the soda it will store it as fat. Use your power rating found in question 3 to calculate how much time you would have to climb stairs, like in the activity, to “burn off” the additional Calories from the can of Mountain Dew. Hint: use your personal power rating calculated in question 3.

Modified from Teaching about Energy by John Roeder