The mass is measured by a balance, but really it measures the weight and from then calculates the mass. Is it possible to trick the balance by making it unstable or changing its orientation so that the weight changes ?

1. Weight on a
slope

2. Who we are
Joël: Hi,I’m Joël, I’m 15 years old. I’m a student at
the CSI and I study in the Portuguese section. I’m
interested in scientific subjects.
Nice to meet you
Véronique: Hello! I'm 15 years old. I am in the
Polish section and I study German and English. I
love sciences, especially astronomy!
See you in space!

3. Noah: Hello. I am Noah and I'm 15
years old. I live in Meulebeke and I
study sciences. See you in space!
Sofia: Hi! I’m Sofia and I am 14
years old. I am Russian but live in
Zwevezele. Nice to meet you!
Hannes: Hello. I am Hannes and I'm
15 years old. I live in Meulebeke and
I study sciences. See you in space!

4. The French part

5. Introduction
Question: The mass is measured by a balance, but really it measures the weight and from then calculates the
mass. Is it possible to trick the balance by making it unstable or changing its orientation so that the weight
changes ?
Hypothesis: The weight changes depending on the inclination of the balance.

6. The experiment
Experiment:
- Measure the weight of the pencil case and the little ball at the normal state (the balance is lying horizontally).
- Tie the balance to the plate.
- Tie the ball to the balance using scotch.
- Tilt the plate to 20° and write down the weight shown by the balance. Same thing, if possible, for 40° and 60°,
otherwise only for 30°.
- Start again replacing the ball with the pencil case. Tie it to the balance with a rope.
Materials:
- a balance
- a pencil case
- a little ball
- rope, scotch
- plate (wooden or plastic)
- a protractor

7. Measuring the weight of the ball
Measuring the weight of the pencil case

8. The results
We noticed that the weight shown by the balance was changing as the inclination was getting bigger (look at the
results below).
We can deduce from that that the weight changes depending on the inclination of the balance.
0° 20° 30° 40°
Mass of the ball
shown by the
balance (g)
14.3 12.1 8.6 4.2
Mass of the pencil
case shown by the
balance (g)
219 205.9 198.9 181.1

9. The Belgian part

10. Introduction
Questions:
-How does your weight change while standing on a slope?
-Is every slope in your school equally steep?
Hypothesis:
-If you stand on a slope your weight does change.
-If the slope is steep, your weight changes more.

11. The experiment
Experiment:
-Put the object on the kitchen balance to weigh.
-Make a slope and measure the weight of the object again. Make the slope steeper
and steeper and measure the weight of the object again.
-Go with the people balance on your way in school and measure if every slope is equally steep.
Material:
-People balance
-kitchen balance
-Wooden shelf and a few blocks to make a slope
-An object which weight will be measured.

13. The results
Doing the experiment:
1
-Read the mass of the object while putting the balance horizontally. Calculate the weight.
-Make a slope by putting Little blocks under the shelfs. Measure the inclination.
-Put the balance on the slope and read the ‘’mass’’ of the object. Calculate the weight.
-Repeat this until you have 5 different slopes.

14. Inclination Read mass (g) Weight (N)
0°(=horizontally) 41.8 0.41
2 blocks 41.8 0.41
4 blocks 39.8 0.39
6 blocks 38.7 0.38
8 blokcs 35.7 0.35

16. 2
-Take the people balance and weigh one of the pupils.
-Calculate the weight.
-Go arounds in school and measure the ‘’mass” of that pupil on different slopes.
-Calculate the weight.
-Try to find at least three slopes.

17. Slopes in school Read mass (kg) Weight (N)
No slope 49.7 0.489
Slope 1 49.6 0.489
Slope 2 49.5 0.485
Slope 3 49.4 0.484

18. Conclusions & reflection
Conclusions:
-If you put an object on a slope, the weight will reduce.
-The bigger the inclination, the smaller the weight.
Reflection:
-On a slope your weight is not the gravity. It’s a component of gravity. That component is smaller than gravity
and the steeper the slope, the smaller the weight.
-Is every slope in our school equally steep?
No, it isn’t.