that work together to
allow the bones to move
in different directions).
For example, your forearm can rotate because
the two bones of your
forearm (the ulna and
radius) are connected by
a pivot joint. These bones
also connect to the humerus bone of the upper
arm by a hinge joint, allowing the forearm to
be raised. The compound joints in your neck
allow your head to move in different directions, including from side to side, nodding up
and down, as well as in a circular motion.
Movable joints need a lubricant (a substance that reduces friction between materials
in contact with each other) and cushioning
(soft padding material) that prevents the bones
from grinding against each other. The ends of
the bones in these joints are covered with cartilage, which acts as a cushion between the
bones. These joints also contain a special fluid
called synovial fluid, which is a lubricant.
ACTIVITY: MOVABLE
Purpose
To make a ball-and-socket joint model.
Material
2-quart (2-L) bowl
1 pound (454 g) instant papier-mâché
(air-dry clay also works well)
2-cup (500-mL) measuring cup
tap water
1-gallon (4-L) resealable plastic bag
craft stick
waxed paper
Procedure
1. In the bowl, mix papier-mâché and water as
indicated on the package.
2. Separate an apple-size piece of papiermâché and place the remaining papiermâché in the resealable bag. Store the bag
in a refrigerator until needed.
3. Break the apple-size piece of papier-mâché
in half. Form one of the pieces into a bowl
shape. Set the bowl on a piece of waxed
paper.
4. Shape the remaining piece of
papier-mâché into a ball.
5. Stick about 1 inch (2.5 cm) of the
craft stick into the ball. Squeeze
the papier-mâché around the
stick to secure it.
6. Cover the end of the ball with
waxed paper. Then stand the
waxed paper-covered ball
inside the papier-mâché
bowl. Reshape the bowl so
that the sides of the bowl
cover most of the ball.
7. With the ball inside the bowl,
allow the bowl and ball to sit
undisturbed overnight. They will
be partially dry in the morning.
36
Gliding Joint
p02.qxd 6/1/04 11:28 AM Page 368. Touching the ball and not the stick, carefully rotate the ball to slightly enlarge the
size of the bowl so that the ball has room
to move and be removed from the bowl.
9. Allow the bowl and ball to sit undisturbed
until they dry. This could take two or
more days.
10. When the papier-mâché pieces are dry,
remove the waxed paper, then hold the
stick and move the ball around inside the
bowl.
Results
You have made a model of a ball-and-socket
joint.
Why?
In a ball-and-socket joint, one bone is movable
and the other is fixed. The movable bone has a
rounded end, represented by the ball-shaped
papier-mâché model. This rounded end fits into
a socket in a fixed bone, represented by the
bowl-shaped papier-mâché model. The bone
with the rounded end can move in all directions, including rotating around. In the shoulder joint, the rounded end of the humerus bone
of the upper arm fits into a bowl-shaped
socket in the scapula (shoulder
bone). You can rotate your arm in a
360° vertical circle.
ON YOUR OWN
1. Use papier-mâché to
make models of a
hinge joint, a pivot
joint, and a gliding
joint like the ones
shown here.
2. Design a way to display your models. One
way is to stand the joint models in front of a
three-paneled backboard. (See Appendix 1
for instructions on making the backboard.)
Information sheets about each model can be
There have been many many topics over the years for science fairs. I believe one of the more popular topics is planets and planetary models. Another topic is the building of a errupting volcano.
about science
Evolutionary Psychology
Decomposition, energy, light, electricity, and photosynthesis are all good science fair topics
If you saw Aa in topics related to Biochemistry, then it stands for amino acids.
Earth science topics that are studied using models include climate change, geological processes like erosion and sedimentation, plate tectonics, and ocean currents. Models are used to simulate and predict how these complex systems may behave under different scenarios, helping scientists understand and make projections about earth processes.
With a simple online search you can find out the technical topics for your presentation. This is a good way to find a topic and get started on your paper.
Some topics you can study using models are Volcanoes, Earth's Structure, and the Solar System.
There have been many many topics over the years for science fairs. I believe one of the more popular topics is planets and planetary models. Another topic is the building of a errupting volcano.
structures
Database,
science
crop cultivation
Some working models on climate change include the Earth System Models (ESMs), which simulate interactions between atmosphere, oceans, land, and ice; Integrated Assessment Models (IAMs), which combine climate models with economic models to project impacts and policy solutions; and Global Circulation Models (GCMs), which simulate climate patterns and predict future climate scenarios based on different emission scenarios. These models help scientists and policymakers understand the complex dynamics of climate change and inform decisions to mitigate its effects.
No, physics is not countable. It is a broad and complex field of science that encompasses various subfields and topics, making it difficult to quantify or categorize in a simple, countable manner.
human subject
about science