1. Measuring Mass and Weight
7.1.5

2. A little review from yesterday… - write these down
What kind of force is gravitation?
Contact force
Force of Motion
Electrical Force
At-A-Distance Force
When would gravity increase?
When you stand on a high mountain.
When you dive deep into the ocean.
When you travel to a planet with larger mass.
When you travel to a planet with smaller mass.

3. So how do we measure gravity?
We use tools called scales!
Technology baby!

4. How to use a spring scale:
Watch your teacher demonstrate, or click on the picture to launch the video.
Measures force in Newtons (N) by determining
how much an object stretches the spring.

5. How to use a digital scale:
Watch your teacher demonstrate, or click on the picture to launch the video.
Uses the weight of an object to calculate its mass in grams (g).

6. How to use a triple beam balance:
Watch your teacher demonstrate, or click on the picture to launch the video.
Measures mass in grams (g) by comparing an object’s mass
to the mass of the sliders.

7. Picture Property Measured Units How does it work?
Spring Scale
Weight
Newtons (N)
An object stretches the spring
Digital Scale
Mass
grams (g)
Uses the weight of an object to calculate mass
Triple Beam Balance
Compares the mass of an object to the mass of the sliders

8. Hands on practice using scales…
4-Put the object back, then select a different object. 5- Repeat until you have measured 4 different objects 6-Tape it into your note book
1- Select an object from the “junk drawer.” 2-Measure the object using an electronic scale a spring scale a triple beam balance 3- WRITE IT DOWN !

9. DAY #2 Exploring Mass and Weight

10. Sketch this chart carefully in your note book:

11. Which of the scales would read the same on another planet? Why?
Right - The triple beam balance would read the same anywhere in the universe.
The triple beam balance would read the same because it is just comparing the mass of two things. Gravity has nothing to do with the measurement.

12. What are the differences among mass and weight and gravity?
Measures how much matter is in an object Measured in grams Changes when you remove part of the object or add to the object

13. What are the differences among mass and weight and gravity?
Measures how much gravity pulls on something Measured in Newtons Changes when you go to another planet or by changing the mass of something.

14. What are the differences among mass and weight and gravity?
Measures the force of attraction between the mass of two objects in a system. Measured in Newtons Changes when the mass of a planet changes OR When the distance between the planets change.

15. Sketch this chart carefully in your note book:
How much matter is in an object
grams
(g)
You remove part of the object or add to it…(cut off an arm or leg)
How much gravity pulls down on something
Newtons (N)
When you go to another planet
Earth vs. Moon
When the mass of the planet changes or when the distance between the 2 objects change
The force of attraction between two objects in a system
Newtons
(N)

16. So why do we say we weigh _____pounds?
A bathroom scale is a type of spring scale.
1 pound =.45 kilograms
100 pounds=45 kilograms

17. 1 pound=4.4 Newtons 100 pounds=440 Newtons
We know from Newton’s 2nd Law that f=ma
So, m=f/a
a= acceleration due to gravity on earth 9.8m/ 𝒔 𝟐
so, mass = 440 N ÷ 9.8m/ 𝑠 2
44.897~45 kg

18. Here are some songs to help you remember what you learned today about mass, gravity, and weight

19. Let me know which one of these songs is your favorite!