Experiment 3 -- Using a salt container with hinged lid
Particles measured:
Rice
Mung beans
Equipment used:
Cardboard box
Container with hinged lid
Empty rectangular container
Clinometer
Method: 1. Place the cardboard box and the rectangular container next to each other.
The cardboard box has to be higher than the container.
2. Fill the hinged-lid container with rice and place it on the cardboard box,
with the lid-side hanging from the edge over the rectangular container.
3. Slightly open the hinged lid for the rice to flow slowly into the container.
4. When the flow stops, measure the angle of repose with the clinometer.
5. Repeat the same procedures for mung beans.
Results: Different particles have different angles of repose
The angle of repose of:
Rice was 38°
Mung beans was 31°
Comments: The more the lid was open, the greater was the force of the particles dragging
each other down, resulting in a gentler slope. Therefore caution has to be taken to
make sure the lid is open just wide enough for the particles to come out.
