# Physical science

## thick stick to hold onto

sound: Prepare in advance a cutting board and thick wooden stick at least 40 cm long. Say: Remember that soundwaves are created when some energy is applied to the object. Then molecules of the medium start moving pushing other molecules, making them vibrate. That’s how the sound is created. Let's listen to the sound that the stick will create. Take the stick in your right hand and let it drop on the cutting board. Say: bang! can you hear the sound? It is loud and bangy! Let's do it again! Put the stick in the baby's right hand and help the baby strike the stick against the surface of the cutting board. Say: bam, bam, bam! Prompt the baby to hold onto the stick with both hands while lying on the tummy and drag the stick forward to you.

elastisity and plasticity: we know that elasticity is ability of the object to retain its size and shape after removing the force that is applied. If the object does not deform, it is considered very elastic. Let us see if the wooden stick is elastic. We will make an experiment. We will try to squeeze it and see if it will deform. What do you think will happen to the stick if we squeeze it? I think it will not deform at all. Now let's conduct an experiment. Take the stick and try to squeeze it in your right hand. Say: it is very hard to squeeze it. It is impossible, I am not strong enough! Place the stick in the baby's right hand and let the baby try to squeeze it. Help if needed. Say: can you see? We can't squeeze it. We can conclude that wooden stick is not elastic at all. Remember, that plasticity can be tested in the same way. If after squeezing the object retains the new form without rupturing or breaking, it means it is very plastic. Our stick is not plastic, because it do not bend.

Hardness. Say: I wonder if the material the stick is made of is hard. When we say the object is hard, we mean that when I scratch it with another sharp object there is no sign left on it. It is very difficult to leave traces on it. If the object is hard it means it is resistant to permanent shape changes. Do you think the wooden stick is hard? Let's make a hypothesis. I think it is hard. Let us conduct an experiment in order to prove or disprove out hypothesis. We will need a coin for that. Take the wooden stick in the left hand and the coin in the right. Make sure your hands are in front of the baby's face so he can see well what is happening. Say: let's scratch the stick with the coin. Do that. Say: let's observe now. What do you see? Do you see any lines left on the surface of the stick? I see no lines. It means the stick has a hard surface.

Let’s explore if the wooden stick is waterproof and absorbent. A material is waterproof when it repels liquids. What do you think about the stick? Is it waterproof? I think it is. Let's make an experiement to proof or disproof our hypothesis. Take the stick on your left hand and the jar with water in your right. Pour the water over the stick untill all is gone. Then say: we will squeeze the stick and see how much water got into it. Do the procedure. Comment: I see no water coming out of the stick. It seems the stick is waterproof, and not water absorbent.

Glossy/mat: Say: The (object) is shiny/glossy/mat. (glossy - reflects the light, mat - absorbs the light)

Brittleness: DO you think the (object) is fragile? Make an assumption. The characteristic for fragility is brittleness. We will drop the(object) from up to the ground and observe if it breaks. Let’s do an experiment. (Take an (object) and drop it from stretched high hand). Say: look at the (object), it did not break at all! It is not brittle. Or it broke and it is brittle.

Magnetic: Let’s see if it is magnetic. We will get a magnet and put it close to the (object). See: the (object) is on the same place. It does not move so it is not magnetic.

Transparent, translucent, opaque: Hold the (object) in your left hand in front of the baby and say: (baby's name),do you think (object) is see-through? Le's make a hypothesis. I thinks it is. Now we have to make an experiment to prove or disprove it. We will need a dark room and a flashlight. Make the room darker or go to the dark room. Place the object in the left hand and the flashlight in the right hand. Switch the flashlight on and say: let's observe if the light goes through the (object). Say: I can see some light passing through the leaf. It is translucent. (If your leaf is thick – you cant and then the leaf is opaque).

Fluid.Now we will see if the (object) is fluid. My hypothesis is that it is not. We will conduct an experiment in order to check it out. Hold the (object) in your right hand with two fingers if possible. Say: Look! I am holding it and it does not change its shape and does not move at all. It does not flow.

Soluble: Let’s see if it is soluble. What do you think, is it soluble? I guess it is not. Let's again make an experiment and check it out. We will need some water. Take an empty bowl, pour some water into it. Put the leaf into water again. Say: look the leaf does not dissolve in the water. It remains as it is. It means it is not soluble.

Insulator: If we put a lot of leaves together in a pile, they will be a good insulator. They will keep warmth inside.

Burn: (object) contains oxygen molecules and can burn with high temperatures. (explain about your object)

Let’s check if the stick h is made of a ductile material. Let us try to stretch it and observe if it becomes a wire.If it does, then it is ductile. Start stretching. Say: see, the stick is very hard to stretch! It is not stretchable at all. Hence It is not ductile.

Our (object) smells so fresh and nice! Or describe how it smells

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