Year 2 have been learning about life cycles. In Science this week we have been looking at the life cycle of a hen, from an egg to a chick to a hen which lays eggs and the cycle starts again.
We looked at incubation, when the hen sits on the egg; pipping, when the chick uses its beak to break out of the egg and hatching, when the chick comes out of the egg.
To compliment this we did an experiment to have a look at the parts of a hens egg. For the first part we looked at a hen’s egg and discovered that the hard shell had tiny holes in it, so that air could get in.
We cracked it open and had a look at the different parts of the egg including the white which was called the albumen and had a thick and a thin part.
We looked at the germinal disc which is where a fertilised egg would form the chick and the air sac which is where the chick takes it’s first breath.
The second part of the experiment we started the day before by putting 3 eggs into vinegar and leaving them over night. As soon as we put them in the vinegar we could see air bubbles coming off the eggs.
When they looked at them the next day, the vinegar had dissolved the shell and all that was left was the membrane which was holding the rest of the egg together. After having a feel of the egg which had turned from very hard to soft and rubbery feeling, we broke the membrane to see if the vinegar had had an effect on the egg inside. We found that it hadn’t. All the same parts of the egg were there.