# Physical science

## small rubber balls

sound: Prepare in advance a cutting board and several small rubber balls. Say: let's listen to what sound the balls 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 ball will create. Take the ball in your right hand and let it drop on the cutting board. Say: can you hear the sound? Say: Pow! can you hear the sound? It is quite an audible one and a bit bangy! Let's do it again! Put the ball in the baby's right hand and help the baby strike the ball against the surface of the cutting board. Say: bong, bong, bong!

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 rubber ball is elastic. We will make an experiment. We will bend it and see if it will deform. What do you think will happen to the ball? I think it will bend. Now let's conduct an experiment. Take one ball and squeeze it in your right hand. Place another ball in the baby's right hand and let the baby squeeze it. Help if needed. Observe the ball. Say: I see that he ball does not get deformed, it recomes back to its round form. Hence we can conclude that rubber is an elastic material. 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 ball is not plastic, because it regains its original shape.

Hardness. Say: I wonder if the material the ball 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 ball is hard? Let's make a hypothesis. I think it is not very hard. Let us conduct an experiment in order to prove or disprove out hypothesis. We will need a coin for that. Take the ball 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 ball 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 tool? I see a few lines. It means the ball has a surface that is not very hard.

Let’s explore if the rubber ball is waterproof and absorbent. A material is waterproof when it repels liquids. What do you think about the ball? Is it waterproof? I think it is. Now let's make an experiment to prove our hypothesis. Take a large pot. Put a jar/cup into it. Put the ball on top of the jar/cup wodden part up so it will cover the opening like a lead. Say: let’s observe. Poor water on the ball. Say: the ball is waterproof; water can't go through the ball into the jar/cup. What is absorbancy then? It is ability of any material to soak up the water, right? What do you see happened to the ball? See it soaked up some water. Let’s try to squeeze the ball now to see how much water got into it. Squeeze it. Say: see, there is no water coming out of it. The ball is not 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 ball 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 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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