GSEB Class 6 Science Solutions Chapter 8 શરીરનું હલનચલન

Textbook Questions and Answers

1. Fill in the blanks.

Question 1. Joints of bones help the body in movement.
Answer: Joints of bones help the body with movement.
In simple words: Bones connect at joints, and these connections allow the body to move and bend.

Exam Tip: Remember that joints are essential for any movement, from simple bending to complex actions.

Question 2. Bones and cartilage together form the body's skeleton.
Answer: Bones and cartilage together make up the body's skeleton.
In simple words: The skeleton is made from bones and a softer material called cartilage.

Exam Tip: Understand that the skeleton is the framework of the body, providing support and shape.

Question 3. Elbow bones are joined by hinge joints.
Answer: The bones in the elbow are connected by hinge joints.
In simple words: Your elbow has a hinge joint, which is like a door hinge, allowing movement in only one direction.

Exam Tip: Hinge joints allow movement in a single plane, similar to a door, found in places like elbows and knees.

Question 4. When moving, bones are pulled by the contraction of muscles.
Answer: When movement occurs, bones are pulled by the muscle's contraction.
In simple words: Muscles pull on your bones to make you move.

Exam Tip: Always remember that muscles contract and relax to create force, which then moves the bones at their joints.

2. Write True [T] or False [F] for the following statements:

Question 1. The movement and gait of all animals are the same.
Answer: F
In simple words: Different animals move in different ways.

Exam Tip: Consider various animals like snakes, birds, and humans; their methods of movement are very different.

Question 2. Cartilage is harder than bone.
Answer: F
In simple words: Cartilage is softer than bone.

Exam Tip: Cartilage is a flexible tissue, unlike the rigid structure of bones.

Question 3. Finger bones do not have joints.
Answer: F
In simple words: Your fingers have many joints that let them bend.

Exam Tip: Try bending your fingers; the ability to bend clearly indicates the presence of multiple joints.

Question 4. There are two bones in the forearm.
Answer: T
In simple words: Your forearm contains two bones.

Exam Tip: The forearm contains the radius and ulna, allowing for rotation and flexibility.

Question 5. Cockroaches have an exoskeleton.
Answer: T
In simple words: Cockroaches possess an outer skeleton.

Exam Tip: An exoskeleton is a hard outer covering that provides support and protection, common in insects.

Question 3. Match the words given in Column 'I' with one or more statements given in Column 'II':

Exam Tip: When matching, carefully read all options in both columns before making a choice, as some items may have multiple correct matches.

4. Answer the following questions:

Question 1. What is a ball-and-socket joint?
Answer: A ball-and-socket joint happens when the rounded end of one bone fits into a cup-shaped hollow in another bone. This design allows movement in all directions at the specific joint. For example, the connection between the two bones in your shoulder is a type of ball-and-socket joint.
In simple words: A ball-and-socket joint lets you move your limb in many directions, like your shoulder or hip.

Exam Tip: To score full marks, define the joint, explain its range of motion, and provide a clear example.

Question 2. Which bone of the skull moves (has movement)?
Answer: The lower jaw bone is the only part of the skull that can move.
In simple words: Only your bottom jaw bone moves in your skull.

Exam Tip: This is a specific fact; ensure you remember that most skull bones are fused and immovable, except for the mandible.

Question 3. Why can our elbow not bend backward?
Answer: Our elbow cannot bend in a backward direction. This occurs because the elbow bone is connected by a hinge joint, which only allows bending in a forward motion.
In simple words: Your elbow can't bend backward because it has a hinge joint that only moves forward, just like a door hinge.

Exam Tip: Clearly state the type of joint and its characteristic range of motion to explain why backward bending is impossible.

Understanding Textbook Activities

Activity 1:

To understand the importance of bone joints. Materials - Ruler, strong thread.

Method:

1. Take a long ruler.

2. Place this ruler on your arm as shown in the figure, so that your elbow remains in the middle of the ruler.

3. Ask your friend to tie the ruler and your hand together.

4. Now try to bend your elbow. Can you bend it?

Observation: The elbow cannot be bent.

Conclusion: Without joints, it's not possible to bend limbs that have continuous bones. Joints are very important for allowing limbs to flex.

Exam Tip: When describing an activity, clearly state the objective, materials, method, and observation, followed by a conclusion based on the results.

Activity 2:

To understand the structure and function of a ball-and-socket joint by making a model. Materials: Paper strip, old plastic ball, bowl, paper cylinder.

Method:

1. Roll a strip of paper into a roller shape (cylinder).

2. Make a hole in an old plastic ball and insert the rolled paper cylinder into it as shown in the figure.

3. Place the ball in a small bowl and try to rotate it in all directions. Does the ball rotate freely in all directions in the bowl? Does the paper roller also rotate?

Explanation: Picture the paper roller as your leg and the ball as its end. The bowl represents the hip area, connecting your leg. A rounded, ball-shaped part of one bone fits into a cup-like space of another bone. This kind of joint offers full movement in every direction.

Exam Tip: When using models, clearly relate each part of the model to the real anatomical structure it represents for better understanding.

Activity 3:

To understand the structure and function of a hinge joint by making a model. Materials: Two cardboards, pencil.

Method:

1. Make a cardboard cylinder.

2. Make a hole in the middle of the cardboard cylinder and insert a pencil into it.

3. Take another piece of cardboard and bend it so that it becomes a half-cylinder.

4. Place the full cylinder on top of the half-cylinder so that the full cylinder can rotate easily.

5. Try to rotate the cylinder with the pencil inserted. What kind of motion does it make?

This motion resembles how a hinged door moves. From this model, we can understand that bones at the knee and elbow hinge joints can only move in one single direction.

Exam Tip: Analogies like a hinged door help visualize the limited movement of hinge joints, making the concept easier to grasp.

Activity 4:

To understand the structure of the rib cage (chest cage).

Method:

1. Take a deep breath and hold it for some time.

2. Gently press the bones of your chest and back to feel your bones.

3. Try to count the number of ribs. Compare the number of chest bones by looking at a diagram.

Conclusion: The rib cage comprises a single chest bone and 24 ribs, which gives a total of 25 bones.

Exam Tip: Understanding the number and arrangement of bones in the rib cage helps appreciate its protective role for vital organs.

Activity 5:

To observe the movement of an earthworm.

Method:

1. Observe the movement of an earthworm walking on the ground.

2. Pick it up, place it on a filter paper, and observe its movement.

3. After that, place the earthworm on a glass slide and observe its movement.

Observation: An earthworm cannot move on very smooth surfaces like glass. It can, however, move well in soil. It does not possess any bones. The rings on its body, along with its muscles and bristles, help it to move along.

Exam Tip: Note how different surfaces affect movement, and pay attention to specific body parts (rings, muscles, bristles) that aid locomotion in organisms without limbs.

Activity 6:

To observe the movement of a snail.

Method:

1. Place a snail on a glass plate and observe its movement.

2. When it starts to move, lift the glass plate and observe its movement from below.

3. Now carefully tilt the glass plate and observe the wave-like motion of its foot.

Observation: A snail has a noticeable thick, fleshy structure, which is its foot. It uses this foot to move around.

Exam Tip: Observing from below helps to clearly see the wave-like muscular contractions of the snail's foot, which is crucial for its slow, gliding movement.

Activity 7:

To observe the body parts that help in the movement of a cockroach.

Method: Observe the body of a cockroach and its movement.

Observation: 1. A cockroach has three pairs of legs, which assist it in walking. 2. It also has two pairs of wings, which enable it to fly. 3. Special muscles near its walking legs and the shape of the front part of its legs help it grip surfaces, allowing it to walk on walls.

Exam Tip: Understand that cockroaches are adapted for both walking and flying, with specific body structures like legs, wings, and gripping mechanisms for varied movements.

Activity 8:

To understand how the streamlined body structure of a fish helps it swim in water. Materials: Paper, wide container filled with water.

Method:

1. Make a paper boat.

2. Place the boat on water filled in a wide container.

3. Push the boat from its pointed end. See what happens.

4. Now push the boat from its broad side. See what happens.

Observation: When the boat is pushed from its pointed end, it easily moves forward.

Conclusion: A fish's body shape is streamlined, much like a boat. This design helps the fish to swim easily through water.

Exam Tip: The principle of streamlining is key for efficient movement through fluids; relating it to a fish helps grasp how shape reduces resistance.