# Physical science

## paper balls

sound: Prepare in advance a cutting board and several paper balls. Say: let's listen to what sound a paper ball will make. 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 paper ball will create. Take a paper ball in your right hand and let it drop on the cutting board. Say: can you hear the sound? It seems that the paper ball is so light, that almost no sound is produced by it! Let's do it again! Put one paper ball in the baby's right hand and let the baby try to squeeze, crinkle and fold it. Say: can you hear any sound?

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 paper ball is elastic. We will make an experiment. We will squeeze it and see if it will deform. What do you think will happen to the paper ball? I think it will squeeze little. Now let's conduct an experiment. Take the paper ball and squeeze it in your right hand. Place another paper ball in the baby's right hand and let the baby squeeze it. Help if needed. Observe the object. Say: I see that paper ball deformed very little, it retains its round shape. Hence we can conclude that this material is elastic. Remember, that plasticity can be tested in the same way. If after bending the object retains the new form without rupturing or breaking, it means it is very plastic. Our paper ball is not plastic.

Hardness. Say: I wonder if a paper ball is hard. When we say the object is hard, we mean next: 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 paper ball is hard? Let's make a hypothesis. I think it is not hard. Let us conduct an experiment in order to prove or disprove our hypothesis. We will need a coin for that. Place a piece of the paper ball on the cutting board holding it by your left hand and take the coin in your right hand. 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 object with the coin. Do that. Say: let's observe now. What do you see? Do you see any holes left on the surface of the paper ball? Did the surface get deformed? Yes. It did. It means the paper ball is a soft object, not hard.

Let’s explore if paper balls are waterproof and absorbent. A material is waterproof when it repels liquids. What do you think about the paper ball? Is it waterproof? I think it is not. Now let's make an experiment to prove our hypothesis. Take a large pot. Put a jar/cup into it. Put a large paper ball on top of the jar/cup so it will cover the opening like a lead. Say: let’s observe. Poor water on the paper ball for as long as it may take untill the ball become all soaked up with water. Say: the paper material is not waterproof; water can go through it into the jar/cup. Paper ball is actually water absorbant.

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 paper balls are made of a ductile material. Let us try to stretch one ball and observe if it becomes a wire.If it does, then it is ductile. Start stretching. Say: see, the ball easily torn once stretched. 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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