1. How does altitude affect the boiling point of water?

2. How does altitude affect the boiling point of water?
Gather your data

3. Altitude vs. Boiling Point of Water
Altitude (ft)
Boiling Point (oF)
0 ft.
212.0º
1000 ft.
210.1º
2000 ft.
208.1º
3000 ft.
206.2º
4000 ft.
204.3º
5000 ft.
202.4º
6000 ft.
200.6º
7000 ft.
198.7º
8000 ft.
196.9º
9000 ft.
195.0º
10000 ft.
193.2º
Altitude (ft)
Boiling Point (oF)
11000 ft.
191.4º
12000 ft.
189.7º
13000 ft.
187.9º
14000 ft.
186.1º
15000 ft.
184.4º
16000 ft.
182.7º
18000 ft.
179.2º
20000 ft.
175.9º
25000 ft.
167.8º
29000 ft.
161.5º
30000 ft.
160.0º

4. How does altitude affect the boiling point of water?
Gather your data
Plot points representing the data on a grid

5. Plot the points using the data from the table.
Scale the axes as appropriate.

6. How does altitude affect the boiling point of water?
Gather your data
Plot points representing the data on a grid
Draw a curve (line) representative of the data points

7. Altitude vs. Boiling Point of Water
Altitude (ft)
Boiling Point (oF)
0 ft.
212.0º
1000 ft.
210.1º
2000 ft.
208.1º
3000 ft.
206.2º
4000 ft.
204.3º
5000 ft.
202.4º
6000 ft.
200.6º
7000 ft.
198.7º
8000 ft.
196.9º
9000 ft.
195.0º
10000 ft.
193.2º
Draw a line representing the data.
Pick 2 points on the graph and draw a line through those points.

9. How does altitude affect the boiling point of water?
Gather your data
Plot points representing the data on a grid
Draw a curve (line) representative of the data points
Label the graph
Title
Label the axes, including units on each axis

10. How does altitude affect the boiling point of water?
Boiling Point ( F° )
Altitude ( feet )

11. Find an equation of the graphed line
Find the y-intercept of the line, b

12. How does altitude affect the boiling point of water?
The y-intercept is 212
Let b = 212
Boiling Point ( F° )
Altitude ( feet )

13. Find an equation of the line
The y-intercept of the line is b = 12

14. Find an equation of the line
The y-intercept of the line is b = 12
Find the slope of the line, m

15. Find the slope of the line
Use the points: (0 , 212.0) and (10000,193.2)

16. Find an equation of the line
The y-intercept of the line is b = 12
The slope of the line is m =

17. How does altitude affect the boiling point of water?
Boiling Point ( F° )
The equation of the line is:
y = x + 212
Altitude ( feet )

18. How does altitude affect the boiling point of water?
Boiling Point ( F° )
Altitude ( feet )

19. The slope of the line is m = -0.00188
What does that actually mean?

20. How does altitude affect the boiling point of water?
Boiling Point ( F° )
Altitude ( feet )

21. The slope of the line is m = -0.00188
What does that actually mean?
This means that the boiling point of water is lowered by approximately 1.88° for every 1,000 ft. of elevation.

22. Notice the altered recipe and increased cooking time for high altitudes.

23. Why is the boiling point of water lowered at higher altitudes?
Because the air is thinner at higher altitudes, thus there is less pressure there.

24. What is the highest point on the Earth?
Mt. Everest at 29,029 ft.
What is the highest point in the United States?
Mt. McKinley at 20,322 ft.
What is the highest point in Florida?
Britton Hill in Walton County at 345 ft.

25. If you were to take a cup of water to a really high altitude, do you think it’s possible that water could boil at room temperature?

26. At higher altitudes, the pressure is lower and consequently water boils at a lower temperature. What do you think happens to the boiling point of water if you increase the pressure around it?

27. Using a pressure cooker increases the pressure around a liquid, which raises the boiling point of the liquid, allowing food to cook at a higher temperature, which causes the food to cook faster.

28. Exactly what is boiling, anyway?
A liquid boils at a temperature at which its vapor pressure is equal to the pressure of the gas above it. The lower the pressure of a gas above a liquid, the lower the temperature at which the liquid will boil.