4:06 PM

Skeletal System of German Cockroach


Important of skeletal system:
Provide physical support

Attachment for muscles
- function in locomotion

Protection for the bodies
- protect the limb of organism

Exoskeleton
√Skeletal system on the outside of the body.
√Chitin shell is secreted by the mantle.
√Thin sheet of epithelial tissue that extends from body wall.

1st layer: Cuticle
√Made up of very thin laminations of chitin
√Wings, hair, legs
√No cell, unable to grow
√2 parts: epicuticle & procuticle


3 layers of exoskeleton:


2nd layer: Epidermis
Made up of a layer of living cell that secrete chitin making up the outer cuticle.

3rd layer: Basal membrane
Separate epidermis from internal body fluids and organs.

Cockroach molt exoskeleton

√Undergo the growth process
√Exoskeleton will split down the back and force it to climb out from the old cuticle.
√Takes six or seven molts for a newly hatched cockroach to reach sexual maturity.

Molt of exoskeleton:


Attachment of muscles on exoskeleton:
√Join of muscle to part of exoskeleton
√Allow muscle contraction
√Move, fly
Example: flexor and extensor muscle


The two main muscles:
√Extensor tibiae muscle which causes the leg to extend
√Flexor tibiae muscle which causes the leg to flex.
√These tendons can be seen by removing the cuticle from one side of the leg in the joint region.

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2:29 PM

Magnet
Theme: Learning the world around us

Pre-test:

1.1 Magnet can attract or repel each other
  1. Distribute bar magnets to groups. Direct pupils to place magnets 1"-2" apart, oriented so that they attract or repel.
  2. Ask pupils to predict what will occur when iron filings are poured on the paper over the area where the magnets reside.
  3. Pour iron filings on the paper. Pupils observe and record results.
  4. Pupils state the pole of magnet (North and south).


1.2 Handle magnets properly
  1. Teacher divides the students into 3- 4 groups.
  2. Teacher organizes simple quizzes. (the correct ways to handle magnets / how to handle magnets)
  3. Students competitive between each group.
  4. For instance, teacher can show a correct / incorrect way to keep the magnet and asks the students whether it is correct or not. If it is wrong, what should they do.


1.3 Magnets attract some materials
  1. Demonstrate the ability of the lodestone to attract. Ask for explanations. Discuss natural and manufactured magnets.
  2. Participants predict what will happen with sand. Record predictions.
  3. Distribute sand to groups and test.
  4. Groups report results.
  5. Draw inferences through brainstorming.


1.4 Different uses of magnets
  1. Ask participants how they might make a temporary magnet with a nail. Distribute nails and paper clips.
  2. Participants experiment until they get the nail to pick up paper clips (after rubbing one pole of magnet along the length of the nail).
  3. Participants provide explanation/reasoning and the different uses of magnet.


1.5 Magnets have different strengths
  1. Ask participants to explore moving the magnetic objects along the tabletop without touching. Participants explore by placing various types of magnets a distance from the objects and under the tabletop.
  2. Participants draw inferences from data through brainstorming.
  3. Students need to do a conclusion.

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