Blood clotting
Blood clotting is a vital process in the human body that prevents excessive bleeding
when a blood vessel is injured. Interestingly, blood clotting operates as a positive
feedback system, because
1. Injury: When a blood vessel is injured, the body needs to stop the bleeding
quickly
2. Platelet Activation: Platelets stick to the injury site and release chemicals.
3. Clot Formation: Then these chemicals cause more platelets to stick and
release even more chemicals, speeding up the process. The chemicals trigger
a chain reaction that turns a protein in the blood into fibrin, which forms a
clot to stop the bleeding.
4. Loop of Growth: As more fibrin is made, more chemicals are released,
causing the clot to grow faster.
The process keeps speeding up until the bleeding stops and the injury is sealed.
This is positive feedback because each step makes the next one happen more
strongly until the job is done.
• 3 eggs
• 3 glasses (large enough to fit the egg plus liquid)
• 3 butter knives ( para mapush down ung egg habang nasa glass na may liquid)
• White vinegar (about 3 cups)
• Distilled water (about 2 cups)
• Light corn syrup (about 1 ¼ cups)
• Slotted spoon ( para mas madali makuha ung egg sa glass)
• Measuring cup (1 cup)
• Measuring spoons (1 tablespoon and ½ tablespoon)
• Sticky notes and marker ( para Madali malaman kung alin ung nasa glass)
• Scale (optional)
(Egg in vinegar)
The acid in the vinegar dissolves the calcium carbonate of the eggshell, leaving the
egg's membrane intact. This membrane acts as a semi-permeable barrier, allowing
certain substances (like water) to pass through, while blocking others (like large
solutes).
The egg’s membrane allows water molecules to pass through, but it blocks the
movement of larger solutes like sugar or salts.
(Water)
In water, the concentration of solutes is lower compared to inside the egg, so water
moves into the egg, causing it to swell.
(Corn syrup)
In corn syrup, the concentration of solutes is higher outside the egg, so water
moves out of the egg, causing it to shrink.
(Mixed water and corn syrup)
The egg’s size will change, but in a more complex way than in the separate water
and corn syrup cases. The parts of the egg exposed to water will swell as water
moves in, while the parts exposed to corn syrup will shrink as water moves out.
Using a mixture of half water and half corn syrup in the naked egg osmosis
experiment creates an interesting and dynamic situation where osmosis occurs in
both directions at the same time. This experiment helps to illustrate how osmotic
pressure can vary across different parts of the egg, leading to uneven changes in
the egg’s size and shape.
